ASVCP quality assurance guidelines: control of preanalytical, analytical, and postanalytical factors for urinalysis, cytology, and clinical chemistry in veterinary laboratories

Effect of dipotassium-ethylenediaminetetraacetic acid or lithium-heparin treatments and storage times on selected clinicopathologic analytes in equine synovial fluid

BACKGROUND

Sample processing methods and storage time affect the outcome of biochemical analysis.

OBJECTIVES

We aimed to assess the effects of dipotassium-ethylenediaminetetraacetic acid (K2-EDTA) and lithium-heparin treatments and storage times on selected analytes in equine synovial fluid (SF).

METHODS

Approximately 2 mL of SF from each horse (n = 7) were collected via femoropatellar joint arthrocentesis into K2-EDTA-treated bottles (K2-EDTA group), lithium-heparin-treated bottles (heparin group), and plain bottles (control group). The pH was determined using an electronic bench pH meter. The total nucleated cell count (TNCC) of samples was determined by hemocytometer method, while total protein (TP) concentrations, and lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) activities of the samples were determined spectrophotometrically at 2, 8, 24, 48, and 168 hours postcollection while being maintained at approximately 4°C.

RESULTS

TP concentrations in the anticoagulant-treated groups remained stable for 48 hours. TNCCs were stable for 8 hours. However, after 2 hours, ALP, LDH, and pH varied significantly (P < 0.05). At 2  hours, mean ALP and LDH activities were significantly elevated in the lithium-heparin treatment samples, while the activity of these analytes was similar in the K2-EDTA and control groups. At 8  hours, the TNCC and pH were significantly elevated in K2-EDTA treated groups, while values were similar in lithium-heparin and control groups. No significant variation was seen in TP values at 2  hours, irrespective of treatment.

CONCLUSIONS

The analytes-except for TP-became unstable within a few hours postcollection. Lithium-heparin and K2-EDTA treatments significantly altered ALP, LDH, TNCCs, and pH but not the TP concentrations of equine SF. Studies establishing reference intervals for these analytes based on the anticoagulant used are warranted to limit misinterpretations in clinical or research settings.

Analytical performance evaluation of two automated urine sediment analysers using two levels of commercially available quality control material

OBJECTIVES

Evaluate the in-clinic performance of point-of-care sediment analysers, Analyzer V (Vetscan SA, Abaxis) and Analyzer S (SediVue DX, IDEXX), using assayed, bilevel (2 concentrations) urine quality control material to determine if instrument specifications are acceptable for semi-quantitative clinical urine sediment analysis.

MATERIALS AND METHODS

Accuracy, precision and clinical utility of Analyzer V and Analyzer S measurements were evaluated using a bilevel, assayed quality control material in 23 veterinary practices.

RESULTS

Photomicrographs taken by the instruments facilitated manual review and quality assessment. Analyzer V and Analyzer S under-identified the presence of cystine crystals with 83 and 13% inaccuracy in the positive quality control material, respectively. Analyzer V and Analyzer S over-reported bacteria in the sterile quality control material with 82 and 94% specificity, respectively. Analyzer V and Analyzer S reported RBCs and WBCs within manufacturer specifications with excellent sensitivity (93 to 100%) and specificity (100%).

CLINICAL SIGNIFICANCE

Additional improvement is needed to better classify crystal types and reduce false positives for bacteria before clinical use. While normal samples can generally be trusted, a manual review of abnormal samples is required to ensure that clinically important urine components are correctly evaluated. Future studies should evaluate the performance of these instruments with species-specific urine sediment.

Analytical performance evaluation of two automated urine chemistry analysers using two levels of commercially available quality control material

OBJECTIVE

Evaluate two point-of-care urine chemistry analysers, VetScan SA and VetLab UA using assayed, bilevel (two concentrations) urine quality control material to determine if performance is acceptable for semiquantitative clinical urine chemistry analysis.

MATERIALS AND METHODS

Normal and abnormal urine quality control material sent to 23 veterinary practices was evaluated three times by each clinic on in-clinic automated urinalysis instruments. Accuracy, precision and clinical utility were evaluated.

RESULTS

Normal urine quality control material: Results for blood, glucose, ketones and bilirubin were 100% accurate and precise for both analysers, and pH values were accurately acidic to neutral. However, pH from VetScan SA had clinically significant negative bias. Abnormal urine quality control material: VetScan SA: blood, microalbumin and bilirubin were 100% accurate; glucose, ketones, and protein demonstrated ≤10% inaccuracy; pH demonstrated 34% inaccuracy. VetLab UA: blood, ketones and bilirubin were 100% accurate; glucose and protein demonstrated ≤10% inaccuracy; pH was 100% accurately neutral to alkaline.

CLINICAL SIGNIFICANCE

VetScan SA had marked negative pH bias versus VetLab UA resulting in clinically significant, overly acidic results. Specific gravity, nitrite, and leukocyte test pads should not be used. Both instruments had excellent performance in normal quality control material. While blood, glucose, protein and bilirubin are correctly identified as present in abnormal quality control material, exact concentrations cannot be interpreted due to imprecision. Only semiquantitative results, not numerical values implying quantification, should be reported from urine test strips.

Submitting High-Quality Clinical Pathology Samples for Best Results

The reliability of clinical pathology laboratory results is directly related to the sample quality submitted. As such, clinicians must submit the most representative and highest quality sample possible by acquiring, handling, preparing, and shipping samples with utmost care. Cytology and blood smear slides should be evaluated for sufficient densities of intact, well-spread, nucleated cells before submission. Poorly prepared samples may delay or negate results, incurring unnecessary costs for the client and practice. Additionally, all practices should have quality assurance programs that include monitoring of equipment to minimize reporting errors. Maximizing resources is the name of the game!.

Use of urinalysis during baseline diagnostics in dogs and cats: an open survey

OBJECTIVES

To describe how veterinarians utilise and perform urinalyses for dogs and cats.

MATERIALS AND METHODS

A survey, developed and distributed through the Veterinary Information Network, enlisted veterinarians who perform urinalyses for dogs and cats. Participants were directed to question banks based on whether urinalyses were performed in-house, by an outside diagnostic laboratory, or using an in-house automated instrument. Participants using multiple methods were directed to questions that related to the chosen methods.

RESULTS

A total of 1059 predominantly first-opinion clinicians from the USA and Canada completed the survey. Participants performed urinalyses much less frequently than blood work during a routine examination. The most common factors preventing participants from performing a urinalysis with blood work included clients' financial constraints, difficulty obtaining urine and lack of perceived diagnostic need. The most common reasons for submission to a diagnostic laboratory included efficiency, more trusted results and convenience. Speed of obtaining results was the most common reason for performing urinalyses in-house. Of the participants who performed in-house urinalyses, fewer always performed a manual sediment examination (79%) as compared with urine-specific gravity (99%) and manual dipstick (87%).

CLINICAL SIGNIFICANCE

This survey documents that urinalysis is often not used in senior patients as recommended by recent clinical guidelines for dogs and cats which can result in decreased diagnosis and impaired management of subclinical disease. There is significant variability in urinalysis methods despite veterinary guidelines promoting standardisation, and this could lead to inaccurate results.

Comparison of the Anvajo Vet Fluidlab 1 urine sediment analyzer to manual microscopy and Idexx SediVue analysis for analysis of urine samples from cats and dogs

The Vet Fluidlab 1 (Anvajo), a new urine sediment analyzer for use in veterinary medicine, uses holographic microscopy to detect urine sediment particles in uncentrifuged urine. We compared the performance of the Fluidlab to manual microscopy and Idexx SediVue analysis for the detection of RBC, WBC, epithelial cells (EC), struvite crystals (STR), all crystals (CRY), and casts (CST) in urine samples from cats and dogs. The performance of the Fluidlab for the detection of bacteria was compared to bacterial culture. We included 624 urine samples from feline (238; 38%) and canine (386; 62%) patients; 227 samples had been submitted for bacterial culturing. The sensitivity of the Fluidlab compared to manual microscopy was 92.1% for RBC, 90.1% for WBC, 87.5% for EC, 67.6% for STR, 53.9% for CRY, and 12.5% for CST. Specificity was >97% for STR and CST, 90.0% for CRY, 78.4% for WBC, 59.4% for EC, and 55.1% for RBC. Sensitivities and specificities of the Fluidlab for analytes compared to manual microscopy were found to be similar to those obtained by the Fluidlab compared to SediVue analysis. Miscellaneous materials (e.g., lipid droplets, sperm, cell detritus) seemed to be the main reason for the high false-positive rate in RBC and EC classification by the Fluidlab. Detection of bacteria by the Fluidlab compared to bacterial culture had a sensitivity of 89.8% and a specificity of 72.3%. The performance of the Fluidlab is acceptable for the detection of WBC and bacteria; sensitivity for the detection of CRY and CST, and specificity for the detection of RBC and EC, require improvement.

Research-Relevant Clinical Pathology Resources: Emphasis on Mice, Rats, Rabbits, Dogs, Minipigs, and Non-Human Primates

Clinical pathology testing for investigative or biomedical research and for preclinical toxicity and safety assessment in laboratory animals is a distinct specialty requiring an understanding of species specific and other influential variables on results and interpretation. This review of clinical pathology principles and testing recommendations in laboratory animal species aims to provide a useful resource for researchers, veterinary specialists, toxicologists, and clinical or anatomic pathologists.

Scientific and Regulatory Policy Committee Points to Consider: Biological Sample Retention From Nonclinical Toxicity Studies

Samples of biologic specimens and their derivatives (eg, wet tissues, paraffin-embedded tissue blocks, histology slides, frozen tissues, whole blood, serum/plasma, and urine) are routinely collected during the course of nonclinical toxicity studies. Good Laboratory Practice regulations and/or guidance specify minimum requirements for specimen retention duration, with the caveat that retention of biologic specimens need not extend beyond the duration of sample stability. However, limited availability of published data regarding stability for various purposes following storage of each specimen type has resulted in confusion, uncertainty, and inconsistency as to the appropriate duration for storage of these specimens. To address these issues, a working group of the Society of Toxicologic Pathology Scientific and Regulatory Policy Committee was formed to review published information, regulations, and guidance pertinent to this topic and to summarize the current practices and rationales for retention duration through a survey-based approach. Information regarding experiences reaccessing biologic specimens and performing sample stability investigations was also collected. Based on this combined information, the working group developed several points to consider that may be referenced when developing or revising sample retention practices. [Box: see text].

Quantification of normetanephrine in canine urine using ELISA: evaluation of factors affecting results

Catecholamine release increases in dogs with pheochromocytomas and in situations of stress. Although plasma catecholamines degrade rapidly, their metabolites, normetanephrine (NME) and metanephrine (ME), are stable in acidified urine. Our aim was to verify a human urine ELISA kit for the quantification of NME and ME in canine urine and to determine the effects on metabolite stability of sampling time (morning or midday) and day (ordinary or day spent in a clinic). We analyzed 179 urine samples from 17 healthy dogs. For NME, the mean intra-assay CV was 6.0% for all samples and 4.3% for the canine control; inter-assay CVs were 3.3, 3.8, and 12% for high and low concentration human urine positive controls supplied in the ELISA kit and a positive canine control, respectively; spike-recovery was 90-101%. For ME, mean intra-assay CV was 6.5% for samples and 9.0% for the canine control; inter-assay CVs were 12.7, 7.2, and 22.5% for high and low concentration human urine positive controls supplied in the ELISA kit and a positive canine control, respectively; spike-recovery was 85-89%. Dilution recovery was unsatisfactory for both metabolites. Based on our verification results, NME was selected for remaining analyses. We found no effect on NME concentrations of acidification or room temperature storage for up to 24 h. The NME:creatinine ratio was higher after the first of 3 clinic days compared to the same morning (111.2 ± 5.5 vs. 82.9 ± 5.3; p < 0.0001), but not on the other days. NME verification results were generally superior to ME. Dilution studies were unsatisfactory for both metabolites. Given that NME was stable without acidification at room temperature, urine samples can be collected at home. The clinic environment can cause higher NME:creatinine ratios, especially in unaccustomed dogs.

Effect of age, sex, and body size on the blood biochemistry and physiological constants of dogs from 4 wk. to > 52 wk. of age

BACKGROUND

Blood biochemistry and reference intervals help to differentiate between healthy and ill dogs as well as to provide information for the prognosis, evaluation, and monitoring; however, these intervals are often obtained from adult animals. It is essential to understand that puppies and adults are physiologically different, which justifies the need to obtain age-specific biochemical reference intervals. The aim of this research was to assess the potential effect of age, sex, body size, and their interaction on routine biochemical analytes and physiological constants (body temperature, heart rate, and respiratory rate). To carry out the research, we selected 197 healthy dogs of both sexes and different body sizes (small, medium and large) classified by age: group I (4-8 wk), group II (9-24 wk), group III (25-52 wk), and group IV (> 52 wk). The biochemical analysis included the measurement of the enzymatic activity of aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), and the concentrations of cholesterol, triglycerides, total proteins, albumin, globulins, glucose, urea, and creatinine. Statistical analyses used analysis of variance (ANOVA) and a general linear model (GLM), which allows the comparison of multiple factors at two or more levels (p < 0.05).

RESULTS

The results of this study showed that ALT, total protein, albumin, globulin, urea, creatinine, and body temperature levels were lower in puppies than in adult dogs of group IV (p < 0.05), while the enzymatic activity of ALP, LDH, glucose concentration, and heart rate were higher. Whereas sex, body size and the interaction did not show a significant effect (p > 0.05).

CONCLUSIONS

Some biochemical components are influenced by age. For this reason, this manuscript contributes with additional data for the clinical interpretation of blood biochemical results in puppies.

Influence of preanalytical factors on feline proteinuria

BACKGROUND

To date, little information is available about the effect of preanalytical factors on the urinary protein-to-creatinine (UPC) ratio in cats.

OBJECTIVES

We aimed to evaluate the effect of a commercially available cat litter, creatinine measurements at three different dilutions of urine, and different storage conditions on the UPC ratio in cats.

METHODS

Feline urine specimens were prospectively collected. Twenty-two whole-urine specimens were placed uncovered and in contact with cat litter for 1 hour; 25 urine supernatants were diluted 1:10, 1:20, and 1:100 for creatinine measurements. The correlation, difference, agreement, and concordance in classifying specimens according to International Renal Interest Society staging were determined. Storage effects on UPC ratios were assessed in specimens stored for 6 hours at +20℃ (n = 20), 1 week at +4℃ (n = 20), and 3 months at -20℃ (n = 25). Specimens were also subjected to four freeze-thaw cycles (n = 20). Results were compared, and clinical significance was assessed by comparing each UPC ratio to the inter-assay range of the baseline value.

RESULTS

Exposure to cat litter did not affect UPC ratios. A positive proportional bias was found in the 1:100 dilution compared with the 1:20 dilution; however, concordance was high for all comparisons. At +20, +4℃, and after four repeated freeze-thaw cycles, UPC ratios were stable. Compared with baseline values, UPC ratios decreased (P < .01) after 8 and 12 weeks at -20℃. However, all UPC ratios were within the inter-assay variability of the baseline value.

CONCLUSIONS

Exposure to cat litter did not affect UPC ratios, but further studies are necessary to evaluate other potential variables. The effects of the dilutions and storage conditions were clinically acceptable, although the 1:20 and 1:100 dilutions were not perfectly comparable.

Effect of storage time on the urine protein: creatinine ratio in alkaline ovine urine

The urine protein:creatinine (UPC) ratio is considered the reference method to assess proteinuria. Its diagnostic value in ovine medicine needs further elucidation. In population monitoring and/or for research purposes, it is convenient to collect many samples simultaneously and store them for later analysis. However, analyte stability data are required to ensure reliable results. We used 15 of 90 urine samples collected from sheep to assess the effect of storage time on the UPC ratio. After centrifugation, the supernatant of each sample was divided into 6 aliquots. Urine protein and creatinine concentrations were determined immediately in one aliquot using the pyrogallol red and a modified Jaffè method, respectively. The other aliquots were stored at -18°C. Based on the absence of active sediment, alkaline urine pH, and UPC ratio ≥ 0.2, we included 15 samples in our study. The UPC ratio was determined in the stored aliquots 2, 7, 14, 21, and 60 d after collection. The data were analyzed with univariate ANOVA. No significant difference was observed in the urinary concentrations of protein, creatinine, and the UPC ratio (0.8 ± 0.84 in conventional units and 0.09 ± 0.095 in SI units) among different times (p > 0.05). The UPC ratio remained stable for 2 mo in ovine urine samples stored at -18°C.

Baseline urinalysis results in 32 healthy Antillean manatees (Trichechus manatus manatus)

OBJECTIVE

To describe results of analysis of free-catch urine samples collected from Antillean manatees (Trichechus manatus manatus) under human care in the Caribbean.

ANIMALS

32 Antillean manatees in 5 Caribbean oceanaria and rescue centers.

PROCEDURES

Urine samples were obtained by opportunistic free catch during physical examination or through the use of operant conditioning procedures. Urinalyses consisted of macro- and microscopic evaluations, biochemical analyses with test strips, and refractometry. Results were compared for manatees grouped on the basis of age, sex, and habitat.

RESULTS

Urine samples were typically clear, straw colored, and alkaline (mean pH, 8.0); had a urinoid odor and low specific gravity (mean, 1.010); and had results on qualitative test strips that were consistently negative for the presence of glucose, bilirubin, ketones, proteins, nitrites, RBCs, and WBCs. Microscopically, the mean ± SD number of RBCs and WBCs/hpf was 0.5 ± 0.3 RBCs/hpf and 1.1 ± 1.5 WBCs/hpf. The presence of some epithelial cells and crystals was typical. Spermatozoa were found in urine from 1 of 15 sexually mature males, and parasite larvae and eggs were found in urine from 2 manatees.

CONCLUSIONS AND CLINICAL RELEVANCE

Results of the present study yielded the first compilation of baseline urinalysis values in healthy Antillean manatees under human care, which, when combined with physical examination and other diagnostic procedures, can help in monitoring the health of these animals. We encourage the use of free-catch urine collection methods, as used in the present study, for routine urinalyses of manatees under human care in zoos, aquaria, or rescue centers.

Investigation of the effects of storage with preservatives at room temperature or refrigeration without preservatives on urinalysis results for samples from healthy dogs

OBJECTIVE

To compare urinalysis results for canine urine samples stored in preservative-containing tubes at room temperature (20°C to 25°C [68°F to 77°F]) or refrigerated at 4°C (39.2°F) in plain glass tubes with results for the same samples immediately after collection.

SAMPLES

Urine samples from 20 healthy dogs.

PROCEDURES

Urine samples (1/dog) were divided into 6 aliquots (3 in preservative-containing tubes and 3 in plain glass tubes). Preservative-containing tubes were stored at room temperature and plain glass tubes were refrigerated. Urinalysis was performed 0, 24, and 72 hours after collection. Results for both storage conditions were compared with results for a reference sample (the 0-hour [immediate post-collection] aliquot in a plain glass tube) by Spearman correlation analysis with pairwise tests for selected variables.

RESULTS

Physical variables (urine color and turbidity with and without centrifugation) for both storage conditions had high (r_s = 0.7 to 0.9) or very high (r_s = 0.9 to 1.0) degrees of positive correlation with reference sample results at all time points, except for color at 24 hours. Similar results were found for all biochemical variables with storage up to 72 hours. For microscopic characteristics, correlation with reference sample results ranged from low or nonsignificant to very high under both storage conditions.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that if a delay in urinalysis is expected, use of the preservative-containing tubes evaluated in this study may be a viable option for sample storage. Further research is warranted to assess direct comparability of results to those of freshly collected samples and use of these tubes to store samples from dogs with conditions affecting the urinary tract.

Preanalytical variables affecting the measurement of serum paraoxonase-1 activity in horses

Paraoxonase-1 (PON-1) activity is a new inflammatory and oxidative marker. Technical effects and biological factors could affect the accuracy of PON-1 activity measurement. We investigated the effects of storage at different temperatures, repeated freeze-thaw cycles, interferences from hemolytic, lipemic, and icteric samples, and seasonal effects on PON-1 activity in horses. We evaluated 2 substrates with an automated spectrophotometer. Ten equine serum samples were stored under different conditions. Although storage at room (21°C) or refrigeration (4°C) temperature induced a statistically significant decrease (p < 0.05) in PON-1 activity, this is not diagnostically relevant. PON-1 activity in frozen samples (-20°C) was stable for short-term storage; diagnostically significant (p < 0.01) fluctuations were observed after 1 mo. Four repeated freeze-thaw cycles were assessed, and all cycles affected PON-1 activity (p < 0.01); however, this was diagnostically significant only after the 4th cycle. Hemolysis induced an overestimation of PON-1 activity; lipemia and hyperbilirubinemia did not change PON-1 activity. Thirty-four horses were sampled monthly for 1 y, and PON-1 activity was higher in autumn (p < 0.05) and winter (p < 0.05) than in spring and summer.

Utility of commercially available reagent test strips for estimation of blood urea nitrogen concentration and detection of azotemia in pet rabbits (Oryctolagus cuniculus) and ferrets (Mustela putorius furo)

OBJECTIVE

To evaluate the utility of commercially available reagent test strips for estimation of BUN concentration and detection of azotemia in pet rabbits (Oryctolagus cuniculus) and ferrets (Mustela putorius furo).

SAMPLE

65 blood samples from 53 rabbits and 71 blood samples from 50 ferrets of various health statuses.

PROCEDURES

BUN concentrations were measured with a clinical laboratory biochemical analyzer and estimated with a reagent test strip. Results obtained with both methods were assigned to a BUN category (range, 1 to 4; higher categories corresponded to higher BUN concentrations). Samples with a biochemical analyzer BUN concentration ≥ 27 mg/dL (rabbits) or ≥ 41 mg/dL (ferrets) were considered azotemic. A test strip BUN category of 3 or 4 (rabbits) or 4 (ferrets) was considered positive for azotemia.

RESULTS

Test strip and biochemical analyzer BUN categories were concordant for 46 of 65 (71%) rabbit blood samples and 58 of 71 (82%) ferret blood samples. Sensitivity, specificity, and accuracy of the test strips for detection of azotemia were 92%, 79%, and 82%, respectively, for rabbit blood samples and 80%, 100%, and 96%, respectively, for ferret blood samples.

CONCLUSIONS AND CLINICAL RELEVANCE

Test strips provided reasonable estimates of BUN concentration but, for rabbits, were more appropriate for ruling out than for ruling in azotemia because of false-positive test strip results. False-negative test strip results for azotemia were more of a concern for ferrets than rabbits. Testing with a biochemical analyzer remains the gold standard for measurement of BUN concentration and detection of azotemia in rabbits and ferrets.

Frequency and classification of errors in laboratory medicine at a veterinary teaching hospital in the United States

BACKGROUND

The accuracy of laboratory data is of utmost importance. Data regarding laboratory error in human laboratories are often extrapolated into veterinary settings. One study investigated the rate and type of errors in a European commercial veterinary laboratory, but that data might not directly apply to an educational setting.

OBJECTIVES

This study determined the frequency and type of errors in laboratory medicine at a veterinary teaching hospital.

METHODS

Errors associated with clinical pathology samples were recorded over two 60-day periods. The first period included a time when new students and house officers started at the veterinary school. The second time period was 6 months later. The errors were assigned to categories, and the frequency of each was calculated. Sample hemolysis, icterus, and lipemia were evaluated separately using an automated index, as these conditions could be pathologic or the result of error. Frequencies of error and hemolysis, icterus, and lipemia were assessed between the groups.

RESULTS

Total error rates were 4.7% and 3.5% for the first and second periods, respectively. The frequency of each error subclassification was similar to those observed in the veterinary and human literature, with preanalytic error predominating. Statistically significant differences in the overall error rate and percentage of preanalytic errors that occurred outside of and within the laboratory were observed comparing differences between the two periods.

CONCLUSIONS

The overall error rate in this veterinary teaching hospital was slightly higher than that previously reported in other settings, although a proportion of errors was as expected. Areas needing improvement were identified, and strategies to reduce error could be developed.

Capture-induced exertional rhabdomyolysis in the Shortfin Mako Shark, Isurus oxyrinchus

BACKGROUND

Shortfin Mako sharks (Isurus oxyrinchus) are top-order predators in oceanic food chains. They are captured worldwide by commercial and recreational fisheries, but little is known about the effects that fishing has on the homeostasis and longevity of these animals.

OBJECTIVE

This study aimed to assess the health of Shortfin Mako sharks captured by recreational fishers off eastern Australia.

METHODS

Twenty-four sharks were captured, and their gender, length, weight, reproductive maturity, and stage were recorded. After blood and urine collection, serum analytes were quantified using standard biochemical methods, whereas urine was analyzed using semi-quantitative reagent strips, microscopic examination, centrifugation, and ammonium sulfate precipitation tests.

RESULTS

Six Makos presented with red-brown urine. The means of notable serum analytes were as follows: sodium 276 mmol/L, potassium 15.6 mmol/L, inorganic phosphate 10.6 mmol/L, magnesium 3.3 mmol/L, urea 325 mmol/L, creatinine 52 μmol/L, AST 2806 U/L, CK 240938 U/L, lactate 44.4 mmol/L, osmolarity 1160 mmol/L, and pH 7.13. These analytes differed from the respective sand tiger shark reference interval, which was used as a proxy for Makos. The red-brown urine was due to myoglobin and had a mean pH of 5.76 that, when combined with red-brown casts, led to a diagnosis of fishing-induced exertional rhabdomyolysis that occurred secondary to lactic acidosis, hypoxia, and hypovolemia. It was further exacerbated by hyperkalemia and acute renal failure, serious complications that often lead to mortality.

CONCLUSIONS

Practitioners caring for sharks and rays should consider collecting urine from free-living or aquarium animals when they are captured for examination and/or treatment, particularly at times with maximal seawater temperatures.

Practical Tips on Sample Handling for Hematology, Chemistry, and Cytology Testing for Equine Patients:: Getting More Bang for your Buck

Clinical pathology results are only as good as the quality of samples and accompanying information submitted to the diagnostic laboratory. The frustration of nondiagnostic or equivocal test results can often be avoided by taking the time to follow sample handling and submission guidelines. This article discusses preanalytical errors that commonly affect the accuracy of hematology, chemistry, and cytology testing, and offers practical tips for preventing these errors and maximizing diagnostic yield.

Nonconformities in Veterinary Cytopathological Examinations: A Retrospective Study of Unsuitable Samples for Analysis

The aim of this study was to evaluate the main nonconformities that result in cytopathological samples inappropriate for diagnosis in veterinary medicine. All cytopathological samples, obtained from different canine and feline tissues/lesions, included in the study were received and classified as inconclusive by a single public laboratory of veterinary pathology, located in Pernambuco State, Brazil, between 2012 and 2016. Nonconformities regarding the smear quality, cellularity, presence or absence of hemorrhage, cellular overlapping, desiccation, and presence or absence of necrotic debris and/or artifacts were evaluated. Data were tabulated using Microsoft Excel 2007; absolute and relative frequencies were calculated using EPIINFO 3.5.2. From the 3268 cases received between 2012 and 2016, 190 cases were selected and comprised 514 inconclusive slides. The most frequent nonconformities detected were insufficient/absence of cellularity in 100% (514/514), inadequate submacroscopic presentation in 87% (446/514), and hemorrhage in 69% (356/514) of samples. Other features identified were cellular overlapping in 34% (175/514), inadequate staining in 31% (175/514), artifacts in 30% (154/514), desiccation in 28% (145/514), and necrotic debris in 26% (133/514) of samples. The implementation of laboratory standard operational procedures aimed at maintaining quality is essential. It is necessary to initially identify the main errors occurring in the processing stages as a way to guide and design strategies to avoid them.

Plasma chemistry in nesting leatherback sea turtles (Dermochelys coriacea) from Florida: Understanding the importance of sample hemolysis effects on blood analytes

Plasma chemistry is widely used in diagnostic and research settings in sea turtles. However, plasma discolorations such as hemolysis are often not considered in data interpretation. The objectives of this study were to (1) evaluate the effects of moderate hemolysis on plasma electrolytes, minerals, and proteins using dry chemistry analysis (DCA) and protein electrophoresis from nesting leatherback sea turtles (Dermochelys coriacea) from Florida and to (2) establish blood analyte reference intervals. Twenty-six plasma samples with absence of hemolysis were selected and sub-divided into one non-hemolytic aliquot and an aliquot that was experimentally manipulated to mimic moderate hemolysis. Plasma samples were analyzed for hemoglobin using a handheld photometer; sodium, potassium, chloride, magnesium, calcium, phosphorus, and total protein using DCA; and protein electrophoresis. Packed cell volume and hemoglobin were measured in corresponding whole blood samples. Reference intervals were established. All analytes except calcium and pre-albumin were significantly higher and the calcium:phosphorus and albumin:globulin ratios were significantly lower in hemolytic plasma compared to non-hemolytic plasma. Alpha2-globulins and potassium were the analytes most impacted by hemolysis, averaging 3.3- and 2.0-fold higher in hemolyzed samples, respectively, indicating that (1) hemoglobin migrates into the alpha2-globulin region in this species and (2) notable intracellular potassium is released into plasma with hemolysis. Attempted conversion factors for compensation of hemolysis were considered inaccurate for 4 of 16 analytes due to non-significant regression lines. We also report that PCV provides an estimate of hemoglobin (g/L) using the formula: (2.59 × PCV) + 24.59. Given the spurious effects of hemolysis, the degree of this artifact should be reported with biochemistry data, and samples with moderate to severe hemolysis should be excluded from datasets when interpreting electrolyte, mineral, and protein results. This will ensure accurate data interpretation for individual turtles in rehabilitation or research settings and population-level data relevant to conservation-focused projects.

Effects of marked hypertriglyceridemia and lipid clearance techniques on canine biochemistry testing

Triglyceride concentrations in dogs with hyperlipidemic disorders can exceed concentrations used by assay manufacturers for interference testing. High-speed centrifugation or the polar solvent LipoClear reduce triglyceride concentrations, but efficacy requires evaluation in veterinary species. We determined the effect of marked hypertriglyceridemia on canine biochemistry testing; assessed the ability of high-speed centrifugation or LipoClear to correct lipemic interferences; and determined if LipoClear introduces inaccuracy into biochemistry assays. Fifteen pooled canine serum samples were aliquoted and spiked with equal volumes of water or Intralipid [triglyceride concentration 33.9 mmol/L (3,000 mg/dL)]. Intralipid aliquots underwent lipid removal by high-speed centrifugation or LipoClear treatment, and a water-spiked aliquot underwent LipoClear treatment. Biochemistry panels were performed using a Vitros 4600 chemistry analyzer. Results were compared by paired t-test or Wilcoxon test. Total observed errors were considered clinically acceptable if below veterinary allowable total error (TEa) guidelines. Statistically significant (p ≤ 0.05) interferences were introduced by Intralipid for 15 of 15 analytes. Median observed error exceeded TEa for potassium and enzymatic carbon dioxide, neither of which were identified by the manufacturer as susceptible to lipemic interference. After centrifugation, median observed error exceeded TEa for potassium and chloride. LipoClear treatment resulted in median errors that exceeded TEa for total protein, chloride, and phosphorus. Given that severe lipemia can occur in dogs with primary or secondary hyperlipidemia, veterinary laboratories should perform their own interference testing at triglyceride concentrations relevant to their patient population and provide this information to clinicians to ensure optimal case management.

Effect of dietary status on plasma-fractionated metanephrines in healthy individuals measured by Elisa

Pheochromocytoma is a rare tumor that typically originates in the adrenal glands, often causing the over-production of catecholamines. The aim of this study was to determine whether dietary status could affect the concentration of plasma-fractionated metanephrines. This study was conducted at the Chemical Pathology Laboratory, Royal Hospital, Oman. Three plasma samples were collected from each participant (16 male and 16 female) over three consecutive days (day one: dietary restriction,day two: excess intake of restricted foods, day three: random sample following the typical diet for each participant). Samples were collected and centrifuged to obtain the plasma, which was then stored at -20°C prior to analysis. Metanephrine and normetanephrine concentrations were measured by comparative ELISA. Plasma metanephrine and normetanephrine measured under the three different dietary conditions for each individual were not significantly different and within normal range. Pearson correlation coefficient analysis of plasma concentration of metanephrines within individual patients under the three dietary conditions revealed positive correlation. We found no significant effect of dietary status on plasma metanephrine or normetanephrine concentration. Therefore, samples taken under any dietary condition may be used to determine plasma MN and NMN concentration. However, dietary restrictions in the diagnosis of Pheochromocytoma need further investigations.

Baseline urinalysis values in common bottlenose dolphins under human care in the Caribbean

Urinalysis is a rapid, simple, inexpensive, and reliable test that documents urine abnormalities reflecting various types of renal, hormonal, or metabolic diseases. Urinalysis could assist proper monitoring of the health of dolphins under human care; however, normal baseline values for dolphin urinalysis have not been reported, to our knowledge. We sampled urine from 193 common bottlenose dolphins ( Tursiops truncatus), living under human care in 24 Caribbean dolphinariums, by voluntary free-catch and analyzed the urine for chemical and microscopic variables using multi-agent dry reagent chemistry dipstick test strips, dedicated pH reagent strips, and unstained sediment slides. Most urine was clear, pale yellow to dark yellow, and had a fishy odor. Dipstick glucose, bilirubin, ketones, and nitrites were negative in all dolphins. The urine pH was acidic ( x¯ ± SD; 5.88 ± 0.58) and specific gravity (SG) was 1.035 ± 0.008. Most animals had 0-2 red blood cells and white blood cells per 40× field, and were negative for proteins. On microscopic sediment, 42.7% of samples had few-to-many squamous epithelial cells; hyaline and epithelial casts were observed only rarely. Crystals were observed in 36.6% of the samples; most were calcium oxalate dihydrate (48.2%) and amorphous urates (42.4%). The values obtained in our study can be used as a reference for health monitoring of dolphins in dolphinariums, and to monitor renal conditions and function in dolphins being rehabilitated or under human care.

Sample Collection

Results may be changed with suboptimal sample collection and transport, which then result in incorrect diagnoses. Quality management of samples must start in the patient, extend through sampling itself, include appropriate short transport, and then be correctly accessioned at the referral laboratory or in-house station to ensure accurate diagnosis of disease. A quality assurance plan at the laboratory chosen is mandatory under American Society for Veterinary Clinical Pathology guidelines.

Clinical utility of currently available biomarkers in inflammatory enteropathies of dogs

Chronic inflammatory enteropathies (CIE) in dogs are a group of disorders that are characterized by chronic persistent or recurrent signs of gastrointestinal disease and histologic evidence of mucosal inflammation. These CIEs are classified as either food-responsive, antibiotic-responsive, or immunosuppressant-responsive enteropathy. Patients not clinically responding to immunomodulatory treatment are grouped as nonresponsive enteropathy and dogs with intestinal protein loss as protein-losing enteropathy. Disease-independent clinical scoring systems were established in dogs for assessment of clinical disease severity and patient monitoring during treatment. Histopathologic and routine clinicopathologic findings are usually not able to distinguish the subgroups of CIE. Treatment trials are often lengthy and further diagnostic tests are usually at least minimally invasive. Biomarkers that can aid in defining the presence of disease, site of origin, severity of the disease process, response to treatment, or a combination of these would be clinically useful in dogs with CIE. This article summarizes the following biomarkers that have been evaluated in dogs with CIE during the last decade, and critically evaluates their potential clinical utility in dogs with CIE: functional biomarkers (cobalamin, methylmalonic acid, folate, α1 -proteinase inhibitor, immunoglobulin A), biochemical biomarkers (C-reactive protein, perinuclear anti-neutrophilic cytoplasmic antibodies, 3-bromotyrosine, N-methylhistamine, calprotectin, S100A12, soluble receptor of advanced glycation end products, cytokines and chemokines, alkaline phosphatase), microbiomic biomarkers (microbiome changes, dysbiosis index), metabolomic biomarkers (serum metabolome), genetic biomarkers (genomic markers, gene expression changes), and cellular biomarkers (regulatory T cells). In addition, important performance criteria of diagnostic tests are briefly reviewed.

Evaluation of an ELISA for metanephrines in feline urine

Catecholamines can be used to evaluate neuroendocrine tumors, stress, and potentially pain, but catecholamines degrade rapidly. Their metabolites normetanephrine (NME) and metanephrine (ME) have better stability in urine. In cats, urine sampling in a home environment would be beneficial to reduce effects of clinical stress and simplify sampling. We evaluated a human urine ELISA for analysis of NME and ME in feline urine, and investigated the effects of acidification, cat tray pellets, and storage time at room temperature up to 8.5 h. In 26 feline urine samples, mean NME concentration was 192 ± 80 ng/mL, mean intra- and inter-assay CV was 6.5% and 4.2%, respectively, and spike recovery was 98-101%, but dilutional recovery was unsatisfactory. For ME, mean intra- and inter-assay CV was 10.2% and 4.1%, respectively. Mean urine ME concentration was 32.1 ± 18.3 ng/mL, close to the kit's lowest standard, and spike recovery was 65-90%; the ELISA could not be validated for ME. The stability study, performed for NME on 12 urine samples, did not identify differences between acidified and non-acidified samples, cat tray pellets, or storage time, and no interaction effects. The ME ELISA was not suitable for feline urine; performance of the NME ELISA was acceptable, except for dilution recovery. For analysis of NME, feline urine can be sampled at home using cat tray pellets and stored at room temperature up to 8.5 h without acidification.

Evaluation of the analytical variability of dipstick protein pads in canine urine

BACKGROUND

The dipstick is a first-line and inexpensive test that can exclude the presence of proteinuria in dogs. However, no information is available about the analytical variability of canine urine dipstick analysis.

OBJECTIVES

The aim of this study was to assess the analytical variability in 2 dipsticks and the inter-operator variability in dipstick interpretation.

METHODS

Canine urine supernatants (n = 174) were analyzed with 2 commercially available dipsticks. Two observers evaluated each result blinded to the other observer and to the results of the other dipstick. Intra- and inter-assay variability was assessed in 5 samples (corresponding to the 5 different semi-quantitative results) tested 10 consecutive times over 5 consecutive days. The agreement between observers and between dipsticks was evaluated with Cohen's k test.

RESULTS

Intra-assay repeatability was good (≤3/10 errors), whereas inter-assay variability was higher (from 1/5 to 4/5 discordant results). The concordance between the operators (k = 0.68 and 0.79 for the 2 dipsticks) and that of the dipsticks (k = 0.66 and 0.74 for the 2 operators) was good. However, 1 observer and 1 dipstick overestimated the results compared with the second observer or dipstick. In any case, discordant results accounted for a single unit of the semi-quantitative scale.

CONCLUSIONS

As for any other method, analytic variability may affect the semi-quantitation of urinary proteins when using the dipstick method. Subjective interpretation of the pad and, to a lesser extent, intrinsic staining properties of the pads could affect the results. Further studies are warranted to evaluate the effect of this variability on clinical decisions.

A new automated turbidimetric immunoassay for the measurement of canine C-reactive protein

BACKGROUND

In dogs, as in humans, C-reactive protein (CRP) is a major acute phase protein that is rapidly and prominently increased after exposure to inflammatory stimuli. CRP measurements are used in the diagnosis and monitoring of infectious and inflammatory diseases.

OBJECTIVES

The study aim was to develop and validate a turbidimetric immunoassay for the quantification of canine CRP (cCRP), using canine-specific reagents and standards.

METHODS

A particle-enhanced turbidimetric immunoassay was developed. The assay was set up in a fully automated analyzer, and studies of imprecision, limits of linearity, limits of detection, prozone effects, and interferences were carried out. The new method was compared with 2 other commercially available automated immunoassays for cCRP: one turbidimetric immunoassay (Gentian CRP) and one point-of-care assay based on magnetic permeability (Life Assays CRP).

RESULTS

The within-run and between-day imprecision were <1.7% and 4.2%, respectively. The assay quantified CRP proportionally in an analytic range up to 150 mg/L, with a prozone effect appearing at cCRP concentrations >320 mg/L. No interference from hemoglobin (20 g/L), triglycerides (10 g/L), or bilirubin (150 mg/L) was detected. Good agreement was observed between the results obtained with the new method and the Gentian cCRP turbidimetric immunoassay.

CONCLUSIONS

The new turbidimetric immunoassay (Turbovet canine CRP, Acuvet Biotech) is a rapid, robust, precise, and accurate method for the quantification of cCRP. The method can be easily set up in automated analyzers, providing a suitable tool for routine clinical use.

Clinical application of biological variation data to facilitate interpretation of canine and feline laboratory results

Interpretation of laboratory results is based on comparison of the patient's own results against established decision thresholds or reference intervals in the context of the clinical presentation and history. Blood measurand analysis has pre-analytical, analytical and physiological sources of variation, which may complicate interpretation of results. Biological variation describes the physiological random fluctuation of blood measurands around a homeostatic set point, which varies within and between individuals. This article reviews the practical applications of biological variation in the everyday clinical setting. Examples are offered to highlight how biological variation can be used to: (1) assess the usefulness of subject-based reference intervals, (2) determine measurand homeostatic set points, (3) interpret single or serial results for diagnosis of disease and (4) evaluate changes in serial results during monitoring.

BRIDGING GAPS BETWEEN ZOO AND WILDLIFE MEDICINE: ESTABLISHING REFERENCE INTERVALS FOR FREE-RANGING AFRICAN LIONS (PANTHERA LEO)

The International Species Information System has set forth an extensive database of reference intervals for zoologic species, allowing veterinarians and game park officials to distinguish normal health parameters from underlying disease processes in captive wildlife. However, several recent studies comparing reference values from captive and free-ranging animals have found significant variation between populations, necessitating the development of separate reference intervals in free-ranging wildlife to aid in the interpretation of health data. Thus, this study characterizes reference intervals for six biochemical analytes, eleven hematologic or immune parameters, and three hormones using samples from 219 free-ranging African lions ( Panthera leo ) captured in Kruger National Park, South Africa. Using the original sample population, exclusion criteria based on physical examination were applied to yield a final reference population of 52 clinically normal lions. Reference intervals were then generated via 90% confidence intervals on log-transformed data using parametric bootstrapping techniques. In addition to the generation of reference intervals, linear mixed-effect models and generalized linear mixed-effect models were used to model associations of each focal parameter with the following independent variables: age, sex, and body condition score. Age and sex were statistically significant drivers for changes in hepatic enzymes, renal values, hematologic parameters, and leptin, a hormone related to body fat stores. Body condition was positively correlated with changes in monocyte counts. Given the large variation in reference values taken from captive versus free-ranging lions, it is our hope that this study will serve as a baseline for future clinical evaluations and biomedical research targeting free-ranging African lions.

Spurious Results in Mineral and Electrolyte Analysis

Assessment of health status and the course of treatment of patients are often determined by results obtained from analysis of blood parameters. Errors in results can occur and cause inappropriate interpretation of laboratory data and, therefore, disease states. Electrolytes and minerals are particularly prone to spurious results; therefore, it is critical that factors influencing inappropriate resulting be recognized, and steps taken to minimize them.

Recognizing and Reducing Analytical Errors and Sources of Variation in Clinical Pathology Data in Safety Assessment Studies

Veterinary clinical pathologists are well positioned via education and training to assist in investigations of unexpected results or increased variation in clinical pathology data. Errors in testing and unexpected variability in clinical pathology data are sometimes referred to as “laboratory errors.” These alterations may occur in the preanalytical, analytical, or postanalytical phases of studies. Most of the errors or variability in clinical pathology data occur in the preanalytical or postanalytical phases. True analytical errors occur within the laboratory and are usually the result of operator or instrument error. Analytical errors are often ≤10% of all errors in diagnostic testing, and the frequency of these types of errors has decreased in the last decade. Analytical errors and increased data variability may result from instrument malfunctions, inability to follow proper procedures, undetected failures in quality control, sample misidentification, and/or test interference. This article (1) illustrates several different types of analytical errors and situations within laboratories that may result in increased variability in data, (2) provides recommendations regarding prevention of testing errors and techniques to control variation, and (3) provides a list of references that describe and advise how to deal with increased data variability.

Preanalytical Considerations for Joint Fluid Evaluation

Synovial fluid analysis is a key component of the minimum database needed to diagnose and manage primary and secondary articular joint disorders. Unfortunately, preanalytical variables can drastically alter samples submitted for evaluation to veterinary laboratories and it is considered the stage at which most laboratory error occurs. This article addresses common sources of preanalytical variability and error that are seen in veterinary medicine. With consistent quality control and reporting of specimens, downstream clinical decision making and management of patients can be accelerated and improved.

Urine Cytology: Collection, Film Preparation, and Evaluation

Cytologic examination of the urine sediment in animals suspected of having urinary tract disease or lower urinary tract masses is one of the best means of distinguishing inflammation, infection, and neoplasia and can help determine if a positive dipstick result for hemoglobin/blood is due to hemorrhage or blood contamination. The quality of the specimen collection and handling plays an important role in the quality of results, the validity of interpretations, and selection of appropriate course of action. The method of sample collection aids localization of pathology. Air dry but do not heat fix, freeze, or expose films to formalin fumes, temperature extremes, or condensation.

Evaluation of cytospin precision in low cellularity canine cerebrospinal fluid

The cell count and differential of cerebrospinal fluid (CSF) cytologic examination classify CSF as inflammatory or not. The cytospin cell yield is related to cell count, but to our knowledge a relationship has not been characterized and cytospin precision is undocumented in any species. The objective of our study was to calculate intra-assay precision of cellular yield and differential on cytocentrifuged canine CSF, determine the factors that may affect precision, and predict the number of cytospins necessary to confirm mild neutrophilic pleocytosis. Ten concurrent replicate cytospins were created from nonhemorrhagic CSF, obtained from 60 dogs in other terminal studies, with either a manual or calibrated pipetting technique. Up to 500 cells per cytospin were counted and classified on each slide. Coefficient of variation (CV), multiple regression, and probabilities were calculated for relationships between cell yield and independent factors including technique, total nucleated cell count, cell differential, and total protein. Manual and calibrated pipetting had similar CVs (average 31%) for total cell yield, but the calibrated technique had fewer foamy macrophages. CV for neutrophil percentage among low cellularity samples with any neutrophils was 146%. Probability based on linear regression showed that 1 cytospin is sufficient to identify samples with >3% neutrophils. Occasional neutrophils, eosinophils, mitotic figures, phagocytic cells, and ependymal cells were seen in many low cellularity canine CSF samples. Canine CSF cytospin cell yield and differential evaluations are imprecise. Calibrated rather than manual pipetting is recommended.

Assessment of the accuracy and precision of the i-Smart 30 VET Electrolyte Analyzer in dogs, cats, cattle and pigs

BACKGROUND

Performance evaluation of point-of-care (POC) electrolyte analyzers is essential for determining their precision and accuracy in clinical practice.

OBJECTIVE

The purpose of this study was to validate the i-Smart 30 VET Electrolyte Analyzer for canine, feline, bovine, and porcine samples in comparison with the ion-selective electrolyte analyzer Roche 9180 electrolyte analyzer.

METHODS

A total of 400 heparinized whole blood samples were collected and analyzed by both instruments for sodium, potassium, and chloride concentrations. Within-run, between-day, and total imprecision were evaluated. Statistical analyses included tests for correlation, regression, bias, and total error.

RESULTS

The coefficients of variation (CV) of both within-run and between-day imprecisions in the i-Smart 30 VET ranged from 0.4-1.6%. In addition, total CV (0.3-1.7%) and total error (0.7-3.7%) of the i-Smart 30 VET were acceptable according to the ASVCP guidelines (< 5%). The correlation between the i-Smart 30 VET and the Roche 9180 was excellent (r > .98). There was no proportional error according to the regression (slope ranges 0.92-1.00, 95% CI includes 1.00), but a constant error was detected for sodium concentration in dogs (interval = 0.5), cattle (interval = 3.0), and pigs (interval = 4.0), and for chloride concentration in cats (interval = 1.0). Most of the bias was within 95% CI, and the total error range (0.8-3.5%) was acceptable according to ASVCP guidelines.

CONCLUSION

The i-Smart 30 VET Electrolyte Analyzer provides precise and accurate measurements of sodium, potassium, and chloride concentrations in whole blood samples from dogs, cats, cattle, and pigs.

ASVCP guidelines: allowable total error guidelines for biochemistry

As all laboratory equipment ages and contains components that may degrade with time, initial and periodically scheduled performance assessment is required to verify accurate and precise results over the life of the instrument. As veterinary patients may present to general practitioners and then to referral hospitals (both of which may each perform in-clinic laboratory analyses using different instruments), and given that general practitioners may send samples to reference laboratories, there is a need for comparability of results across instruments and methods. Allowable total error (TEa ) is a simple comparative quality concept used to define acceptable analytical performance. These guidelines are recommendations for determination and interpretation of TEa for commonly measured biochemical analytes in cats, dogs, and horses for equipment commonly used in veterinary diagnostic medicine. TEa values recommended herein are aimed at all veterinary settings, both private in-clinic laboratories using point-of-care analyzers and larger reference laboratories using more complex equipment. They represent the largest TEa possible without generating laboratory variation that would impact clinical decision making. TEa can be used for (1) assessment of an individual instrument's analytical performance, which is of benefit if one uses this information during instrument selection or assessment of in-clinic instrument performance, (2) Quality Control validation, and (3) as a measure of agreement or comparability of results from different laboratories (eg, between the in-clinic analyzer and the reference laboratory). These guidelines define a straightforward approach to assessment of instrument analytical performance.

The preanalytic phase in veterinary clinical pathology

This article presents the general causes of preanalytic variability with a few examples showing specialists and practitioners that special and improved care should be given to this too often neglected phase. The preanalytic phase of clinical pathology includes all the steps from specimen collection to analysis. It is the phase where most laboratory errors occur in human, and probably also in veterinary clinical pathology. Numerous causes may affect the validity of the results, including technical factors, such as the choice of anticoagulant, the blood vessel sampled, and the duration and conditions of specimen handling. While the latter factors can be defined, influence of biologic and physiologic factors such as feeding and fasting, stress, and biologic and endocrine rhythms can often not be controlled. Nevertheless, as many factors as possible should at least be documented. The importance of the preanalytic phase is often not given the necessary attention, although the validity of the results and consequent clinical decision making and medical management of animal patients would likely be improved if the quality of specimens submitted to the laboratory was optimized.

Best practices for veterinary toxicologic clinical pathology, with emphasis on the pharmaceutical and biotechnology industries

The purpose of this paper by the Regulatory Affairs Committee (RAC) of the American Society for Veterinary Clinical Pathology (ASVCP) is to review the current regulatory guidances (eg, guidelines) and published recommendations for best practices in veterinary toxicologic clinical pathology, particularly in the pharmaceutical and biotechnology industries, and to utilize the combined experience of ASVCP RAC to provide updated recommendations. Discussion points include (1) instrumentation, validation, and sample collection, (2) routine laboratory variables, (3) cytologic laboratory variables, (4) data interpretation and reporting (including peer review, reference intervals and statistics), and (5) roles and responsibilities of clinical pathologists and laboratory personnel. Revision and improvement of current practices should be in alignment with evolving regulatory guidance documents, new technology, and expanding understanding and utility of clinical pathology. These recommendations provide a contemporary guide for the refinement of veterinary toxicologic clinical pathology best practices.