Evaluation of an automated urine chemistry reagent-strip analyzer

Evaluation of the Atellica® UAS 800: a new member of the automated urine sediment analyzer family

BACKGROUND

In 2017 the Atellica^® UAS 800 urine sediment analyzer was introduced by Siemens Healthineers. We investigated its applicability in the standardization and automation of the laboratory urinalysis workflow, including the prediction of urine culture outcome and glomerular pathology.

METHODS

We evaluated the performance characteristics of the Atellica^® UAS 800 and its correlation with the iQ200 (Beckman Coulter). In addition, we studied the agreement between Atellica^® UAS 800 and CLINITEK Novus^® and determined the predictive value of bacteria and leukocyte counts for urine culture outcome. Furthermore, we investigated the ability of Atellica^® UAS 800 to identify pathological casts and dysmorphic erythrocytes in comparison to manual microscopy.

RESULTS

Erythrocyte and leukocyte analyses indicated high intra- and inter-run precisions and good correlations with the iQ200. We found that the Atellica^® UAS 800 detects bacteria with higher sensitivity than the iQ200. The Atellica^® UAS 800 and CLINITEK Novus^® showed a high degree of conformity. We determined seven combinations of clinical cut-off values of bacteria and leukocytes for predicting urine culture outcome with sensitivity, specificity, and negative predictive values of 95%, 52%, and 93%, respectively. Using the Atellica^® UAS 800, hyaline casts, erythrocyte casts, leukocyte casts, and dysmorphic erythrocytes were correctly recognized in 76%, 22%, 2%, and 39% of the samples, respectively.

CONCLUSIONS

The Atellica^® UAS 800 is a robust, fast, and user-friendly analyzer, which accurately quantifies erythrocytes, leukocytes, bacteria and squamous epithelial cells, and may be utilized for predicting positive urine cultures. The detection of clinically important pathological casts and dysmorphic erythrocytes proved insufficient.

Urinary strips for protein assays: easy to do but difficult to interpret!

Urine samples can be readily obtained from patients in everyday clinical practice. Therefore, the availability of urine allows physicians to obtain relevant clinical information in a timely manner. Since the measurement of urinary protein levels is essential in diagnosing and treating a host of diseases, the potential detection of urinary proteins by urinary strips in an easy, quick, and cheap way is very attractive. However, to ensure optimal use of urinary strips, one needs to be aware of their characteristics and their limitations. In this review, we discuss the characteristics of the urinary strips available for testing urinary protein levels and for detecting urinary albumin. We then consider their analytical performances in their most widely used clinical applications (e.g., in pregnancy, chronic kidney disease, diabetes, and screening of the general population).

Study on a novel core module based on optical fiber bundles for urine dry-chemistry analysis

A core module with a novel optical structure is presented to analyze urine by the dry-chemistry method in this paper. It consists of a 32-bit microprocessor, optical fiber bundles, a high precision color sensor and a temperature sensor. The optical fiber bundles are adopted to control the spread path of light and reduce the influence of ambient light and the distance between the strip and sensor effectively. And the temperature sensor is applied to detect the environmental temperature to calibrate the measurement results. Therefore, all these can bring a lot of benefits to the core module, such as improving its test accuracy, reducing its volume and cost, and simplifying its assembly. Additionally, some parameters, including the calculation coefficient about reflectivity of each item, semi-quantitative intervals, the number of test items, may be modified by corresponding instructions in order to enhance its applicability. Meanwhile, its outputs can be chosen among the original data, normalized color values, reflectivity, and the semi-quantitative level of each test item by available instructions. Our results show that the module has high measurement accuracy of more than 95%, good stability, reliability, and consistency and can be easily used in various types of urine analyzers.

Changes in body composition in triathletes during an Ironman race

PURPOSE

Triathletes lose body mass during an Ironman triathlon. However, the associated body composition changes remain enigmatic. Thus, the purpose of this study was to investigate Ironman-induced changes in segmental body composition, using for the first time dual-energy X-ray absorptiometry (DXA) and peripheral quantitative computed tomography (pQCT).

METHODS

Before and after an Ironman triathlon, segmental body composition and lower leg tissue mass, areas and densities were assessed using DXA and pQCT, respectively, in eight non-professional male triathletes. In addition, blood and urine samples were collected for the determination of hydration status.

RESULTS

Body mass decreased by 1.9 ± 0.8 kg. This loss was due to 0.4 ± 0.3 and 1.4 ± 0.8 kg decrease in fat and lean mass, respectively (P < 0.01). Calf muscle density was reduced by 1.93 ± 1.04 % (P < 0.01). Hemoglobin, hematocrit, and plasma [K(+)] remained unchanged, while plasma [Na(+)] (P < 0.05), urine specific gravity and plasma and urine osmolality increased (P < 0.01).

CONCLUSIONS

The loss in lean mass was explained by a decrease in muscle density, as an indicator of glycogen loss, and increases in several indicators for dehydration. The measurement of body composition with DXA and pQCT before and after an Ironman triathlon provided exact values for the loss in fat and lean mass. Consequently, these results yielded more detailed insights into tissue catabolism during ultra-endurance exercise.

Evaluation of the iChem® Velocity™ urine chemistry analyzer in a hospital routine laboratory

BACKGROUND

The novel urine chemistry analyzer iChem Velocity (IRIS Diagnostics) offers improved urinalysis automation options through integration with the well-established iQ200 urine microscopy analyzer. In the course of optimizing the workflow in our hospital routine laboratory, we evaluated the performance of the iChem Velocity.

METHODS

A total of 257 random urine samples were analyzed with the iChem Velocity, iQ200, Clinitek Atlas (Siemens Healthcare Diagnostics) and by manual microscopy.

RESULTS

Depending on the parameter, 93% (hemoglobin) to 100% (urobilinogen), the iChem Velocity and Clinitek Atlas results agreed within the same rank or within one level of difference. The Clinitek Atlas featured a higher sensitivity for hemoglobin (area under the curve 0.86) and leukocyte esterase (area under the curve 0.85) compared with the iChem Velocity (area under the curve for hemoglobin 0.73, leukocytes 0.78). Imprecision was highest for hemoglobin and leukocytes in a pathological sample pool. While the precision of the Clinitek Atlas for hemoglobin measurements was superior, the iChem Velocity was more precise in analyzing protein and pH.

CONCLUSIONS

Through urinalysis automation with the iChem Velocity and iQ200, we achieved a reduction of hands-on time by 89%. The sensitivity of this new system should be further improved through ongoing development.

Measurement of urine pH for epidemiological studies on bladder cancer

Methods for efficiently identifying subjects with constantly acidic pH in epidemiological and clinical studies have not been assessed. We recruited 30 volunteers to estimate the minimum number of urine pH measurements using pH strips needed to identify subjects with "constantly acidic urine pH". Spearman's correlation coefficients between urine pH measured with a pH meter and with the four pH strips ranged from 0.94 to 0.95 (p < 0.001 for all four strips). Overall agreement within +/-0.5 pH units between the four strips and the pH meter ranged from 62.2% to 74.4%. When using a spot urine sample from a single morning to classify participants with respect to their urine pH, 80% of individuals fell into the acidic urine pH (pH equal to or lower than 6.0) group. When we required subjects to have urine pH equal to or lower than 6.0 in six consecutive AM spot urine samples and seven spot PM urine samples, only 20% of participants fulfilled this criterion. Measuring urine pH twice a day (early in the morning and early in the evening) during four consecutive days classified individuals in the same way as two daily measurements for one week. A single pH measurement from a spot urine sample is not reliable to identify individuals with constantly acidic pH. Morning and evening urine pH measurements with pH strips during four consecutive days identify individuals with constantly acidic urine pH individuals as well as one week of measurements, and thus might be useful to identify subjects with constantly acidic urine pH in epidemiological and clinical studies.

Comparison of three automated urinalysis systems--Bayer Clinitek Atlas, Roche Urisys 2400 and Arkray Aution Max for testing urine chemistry and detection of bacteriuria

BACKGROUND

Our study is aimed to determine the performance of 3 automated urinalysis systems-Clinitek Atlas, Urisys 2400 and Aution Max.

METHODS

One thousand urine specimens were analyzed with the 3 automated systems. The results of the 3 assays were compared for testing urine chemistry and evaluating the capacity of leukocyte esterase and nitrite to detect bacteriuria.

RESULTS

The correlation between the 3 instruments represented as within 1 grading difference was better between the Atlas and Aution Max systems for pH, blood, glucose, urobilinogen, ketone and specific gravity. For protein and nitrite, better correlation was observed between the Atlas and Urisys 2400, while the Aution Max and Urisys 2400 conveyed better correlation for bilirubin and white blood cells. The sensitivity and specificity of both the leukocyte esterase and nitrite in screening for significant bacteriuria were 71.7, 58.9, 70.8% and 99.1, 99.1 and 97.2%, for the Clinitek Atlas, Aution Max and Urisys 2400, respectively.

CONCLUSIONS

The automated urinalysis systems demonstrate acceptable correlations with each other in urine chemistries, especially between the Clinitek Atlas and Aution Max systems on the majority of items. The specificity and negative predictive value of leukocyte esterase and nitrite of the 3 instruments for screening of significant bacteriuria were sufficient to avoid unnecessary urine culture.

Evaluation of an automated urinalysis system for testing urine chemistry, microscopy and culture

AIMS

This study was designed to evaluate the performance of an automated urinalysis system that utilised three commercially available instruments, the Clinitek Atlas, Sysmex UF-100 and the Alifax Uro-Quick.

METHODS

The results of the automated system for 818 urine samples were compared with the results of manual processing which consisted of phase contrast microscopy, manual dipstick chemistry analysis and culture onto solid media.

RESULTS

The correlation between the two methods for urine chemistry was excellent with a concordance of 89, 97, 100 and 98% for pH, blood, glucose and protein, respectively. The quantification of red blood cells and white blood cells had an R2 of 0.855 and 0.92, respectively. A difference scatter plot indicated a trend towards the manual cell count being greater than the UF-100 count as both the red and white blood cell count increased. There was 98% agreement between the automated process and manual culture.

CONCLUSIONS

The automated urinalysis system is fully integrated and allows for the cross-checking of urine chemistry and microscopy as well as electronic transfer of data. The automated process was used as a screening procedure and some manual testing was necessary. Automation of urinalysis offers a reduction in variation and has comparable results to manual testing.

Screening school children for albuminuria, proteinuria and occult blood with dipsticks

Beginning in 1974, the Japanese Ministry of Health Welfare directed the screening of schoolchildren for proteinuria. We studied their procedure and methods in 6197 school children and also evaluated a new urine dipstick that measures albumin concentrations down to about 10 mg/l and creatinine down to about 300 mg/l. We used specimens from adult in- and outpatients to test the accuracy of the dipsticks. Based on the quantitative results, we set as cutoffs < 150 mg/l for protein and < 30 mg/l for albumin as the concentrations representing "low risk." The quantitative values were assumed to be correct, and the dipstick results were judged accordingly, i.e., a dipstick protein of > or = "150" mg/l or an albumin of I "30" mg/l indicated increased risk of developing or having a genitourinary disorder. The sensitivity/specificity of the protein dipstick was 95.1%/95.5%, and the same for the albumin dipstick was 83.8%/93.8%. The cut-off for the albumin dipsticks probably should be set somewhat lower to reduce the number of false negatives and increase the sensitivity of the dipstick. When we compared the quantitative albumin to the protein dipsticks with the above cut-offs, we found the sensitivity/specificity to be 79.3%/94.4%, i.e., much like the albumin dipstick results. The many reports on the association of albuminuria and risk of renal disease recommend that screening should be done for albumin rather than protein. Based on the data from the school children, we estimate that a dipstick albumin of "30" mg/l is borderline increased risk, and that a protein dipstick of "150" mg/l is the same. If we call the dipstick "10" mg/l albumin, "30" mg/l albumin and the "150" mg/l protein results "low risk," then we estimate the prevalence of albuminuria in the school children to be about 2.1% and proteinuria to be about 4.3%. Children with these values should have a quantitative test for albumin and protein. We also tested a dipstick for creatinine and found increasing values with increasing age in both genders; the older boys had significantly higher creatinine values than the older girls and younger boys. For the albumin/creatinine ratio, we found 6028 children with a ratio of < 30 mg/g indicating low risk and 159 children with a ratio of > or = 30 mg/g indicating increased risk. The ratio may be more useful owing to the likely reduction of the number of false negatives and false positives.

Evaluation of the CLINITEK ATLAS for routine macroscopic urinalysis

OBJECTIVES

To evaluate the performance of a new, benchtop, fully automated urine analyzer the CLINITEK ATLAS and compare it with the URICHEM 1000 CHEMSTRIP UA analyzer. Macroscopic analysis included measurement of 8 urine analyte chemistries and specific gravity by the refractive index method (SgRl).

METHODS

The analytical performance studies conducted were calibration stability, precision (within-run and day-to-day), comparison of results of 437 fresh patient urine specimens, analysis of time performance, and problem logging over a 16-day evaluation period.

RESULTS

Satisfactory calibration reproducibility, within-run (n = 10), and day-to-day (n = 16) precision was found because results fell within the +/- one color-block by the proposed National Committee for Clinical Laboratory Standards (NCCLS) criteria. Patient results (n = 437) from the 2 analyzers giving the same color-block agreement was found to be for pH, 52%; glucose, 92%; ketones, 86%; protein, 79%; bilirubin, 97%; leukocytes, 72%; blood, 80%; and nitrite, 98%. The concordance defined by the NCCLS criteria as the agreement of results +/- one color-block between the 2 analyzers was found to be for pH, 96%; glucose, 99%; ketones, 100%; protein, 95%; bilirubin, 100%; leukocytes, 97%; and blood 86%. The SgRl determined on ATLAS was correlated with the RD-10 Rapid Density analyzer with the following results: slope = 0.97, intercept = 0.033, r = 0.94, Syx = 0.003, for a range of values from 1.002 to 1.070.

CONCLUSION

Our preliminary data indicate that the analytical performance, and automatable features for complete walk-away function of this analyzer can significantly increase the overall testing efficiency in the urinalysis laboratory.