Use of blood culture vial specimens in intraoperative detection of infection

A retrospective study was performed evaluating the results of three different intraoperative culture techniques and their diagnostic value in determining clinical infection in patients after a total joint replacement. Twenty-four patients (34 cases) met the selection criteria and were evaluated using intraoperatively collected tissue samples, swab samples, and fluid samples injected into standard blood culture vials. Results of the cultures of these specimens were compared with the clinical diagnoses to determine specificity, sensitivity, and accuracy of each technique. The current study suggests the use of fluid aspirate from intraoperative wounds immediately injected into blood culture vials is a highly specific, sensitive, and accurate diagnostic culture technique (100%, 92%, and 94%, respectively). The superiority of vial cultures is enhanced when organisms grown from the liquid media only are discounted as contaminants. This led to significant decreases in the sensitivity and accuracy of swab culture and tissue biopsy results when compared with vial culture results. Thus, vial cultures are a more cost-effective means for intraoperative detection of infection.

Electrophoresis in microfabricated devices using photopolymerized polyacrylamide gels and electrode-defined sample injection

Microfabrication techniques have become increasingly popular in the development of the next generation of DNA analysis systems. While significant progress has been reported by many researchers, complete microfabricated integrated DNA analysis devices are still in the earliest stages of development. Most miniaturized analysis systems have incorporated noncross-linked polymer solutions as the separation medium of choice and the operation of these systems necessitates the use of high electric fields and long separation lengths. In this paper, we present two techniques that may help alleviate this problem and accelerate the development of the so-called 'lab-on-a-chip' systems. We present the use of photodefinable polyacrylamide gels as a sieving medium for DNA electrophoresis. These gels offer the significant advantages of faster curing times, locally controlled gel interface, and simpler handling over chemically polymerized gels. We also introduce an electrode-defined sample compaction and injection technique. This technique helps achieve sample compaction without migration into the gel and offers significant control over the size and application of the sample plug. The use of these technologies for double-stranded DNA separations in microfabricated separation systems is demonstrated.

Comparison of glucose levels in dermal interstitial fluid and finger capillary blood

Alternative methods for self-monitoring of blood glucose have been pursued by many researchers, largely in response to evidence gathered in several long-term studies of patients with diabetes mellitus. These studies suggest that long-term complications of the disease may be mitigated if the disease is intensively managed, a component of which is increased monitoring. Many of the alternative methods utilize interstitial fluid (ISF) as the diagnostic fluid, rather than finger blood. A time lag in the distribution of glucose from blood to the interstitium has been observed by many, with estimates of lag time varying from none to 45 min. Dermal ISF was sampled from diabetic subjects in two tests and compared to finger blood glucose. In the first test, data were collected over time in a manner that allowed a cross-correlation analysis to predict an average lag time. Information from this test was then used as input to a data collection format for a method comparison test of 691 patients with diabetes in which ISF data were collected immediately after the finger blood reference and 15 min after the reference. An average lag time of about 25 min was determined from the cross-correlation analysis, with the correlation error reduced by three-fourths within a 15-min lag time. In the method comparison test, the correlation coefficient between finger blood glucose and ISF glucose improved from 0.923 to 0.951, and the percentage of data in the A zone of the Clarke Error Grid rose from 80.2% to 90.6% for the ISF glucose data collected at no lag and 15-min lag, respectively. Dermal ISF glucose measurement might be a reasonable alternative to blood glucose measurement for patients routinely monitoring ambient glycemia, although more testing in the sensitive hypoglycemic range is needed to clarify what might happen in cases of rapidly changing glucose.

Electroosmosis injection of blood serum into biocompatible microcapillary chip fabricated on quartz plate

A chip which allows the detection of various human health markers from a trace amount of blood has been studied. As a goal, a microcapillary with a 30 x 30 microm cross-section was fabricated using all-dry etching technologies on a 2 x 2 cm SiO2 chip. The coating of the biocompatible 2-methacryloyloxyethylphosphorylcholine (MPC) polymer on the inner quartz wall of the microcapillary demonstrated a sufficiently long adsorption suppression of proteins in the serum on the quartz surface, while rapid stopping occurred for serum injected into the microcapillary with a bare quartz surface. The latter rapid stopping corresponded well to fast electroosmosis flow due to the negatively increasing zeta-potential by the adsorption of proteins on the quartz surface. The electroosmosis pump arranged a downstream of the microcapillary was also developed to inject serum into it. As a preliminary application, a given concentration-standard solution was injected into the ion-sensitive field-effect transistor (ISFET) embedded in the chip, employing the electroosmosis pump arranged downstream of the sensor position. Hence, the pH and Na+ and K+ cation concentrations were measured.

Rapid detection of smear-negative Mycobacterium tuberculosis by PCR and sequencing for rifampin resistance with DNA extracted directly from slides

Conventional methods for identification of Mycobacterium tuberculosis from culture can take 6 weeks. To facilitate the rapid detection of M. tuberculosis and to assess the risks of drug resistance, we developed a technique of eluting DNA directly from sputum slides and performing PCR for the detection of M. tuberculosis DNA, followed by sequencing the rpoB gene to detect rifampin resistance. This entire process requires only 48 h. Forty-seven sputum specimens submitted for microscopy for detection of acid-fast bacilli (AFB) and for mycobacterial culture and susceptibility testing were assessed after elution from the slides and extraction. M. tuberculosis-specific DNA was amplified in a nested PCR with previously described primers (primers rpo95-rpo293 and rpo105-rpo273), followed by analysis on a 4% agarose gel for a 168-bp product. Automated sequencing was performed, and the sequences were aligned against a database for detection of anomalies in the rpoB gene (codons 511 to 533) which indicate rifampin resistance. Of the 47 sputum specimens tested, 51% (24 of 47) were culture positive (time to positive culture, 2 to 6 weeks). Smears for AFB were positive for 58% (14 of 24) of the specimens and were negative for 42% (10 of 24) of the specimens. All 24 culture-positive sputum specimens (14 microscopy-positive and 10 microscopy-negative sputum specimens) were positive by PCR with eluates from the smears. Forty-nine percent (23 of 47) of the sputum specimens were negative for M. tuberculosis by smear, culture, and PCR. Of the isolates from the culture-positive samples, five were rifampin resistant by sequencing; all five were also rifampin resistant by in vitro susceptibility testing. Of these rifampin-resistant M. tuberculosis isolates, two were microscopy negative for AFB. Patients who are negative for AFB and culture positive for M. tuberculosis can now be identified within a day, allowing institution of therapy and reducing isolation time and medical costs.

Electrophoretic injection bias in a microchip valving scheme

The pinched injection strategy, implemented on microfabricated fluidic devices (microchips), was investigated for an electrophoretic injection bias. Both the sample loading and dispensing steps were found to contribute to the injection bias whereby neutral species were injected preferentially to anionic species. In the sample loading step, neutral species filled a larger volume in the cross intersection than anionic species. Similarly, in the dispensing step, a larger volume of neutral analyte was injected than anionic analyte. Up to a 27% difference in injected volumes was observed. Fluorescently labeled amino acids were used as model analytes.

The effects of collection methods on oral fluid codeine concentrations

The use of a variety of alternative biological specimens such as oral fluid for the detection and quantitation of drugs has recently been the focus of considerable scientific research and evaluation. A disadvantage of drug testing using alternative specimens is the lack of scientific literature describing the collection and analyses of these specimens and the limited literature about the pharmacokinetics and disposition of drugs in the specimen. Common methods of oral fluid collection are spitting, draining, suction, and collection on various types of absorbent swabs. The effect(s) of collection techniques on the resultant oral fluid drug concentration has not been thoroughly evaluated. Reported is a controlled clinical study (using codeine) that was designed to determine the effects of five collection techniques and devices on oral fluid codeine concentrations. The collection techniques were control (spitting), acidic stimulation, nonacidic stimulation, and use of either the Salivette or the Finger Collector (containing Accu-Sorb) oral fluid collection devices. Preliminary data were collected from two subjects using the Orasure device. The in vitro drug recovery was also evaluated for the Salivette and the Finger Collector devices. With the exception of a single time point, codeine concentrations in specimens collected by the control method (spitting) were consistently higher than concentrations in specimens collected by the other methods. The control collection concentrations averaged 3.6 times higher than concentrations in specimens collected by acidic stimulation and 1.3 to 2.0 higher than concentrations in specimens collected by nonacidic stimulation or collection using either the Salivette or the Finger Collector devices. When calculated using oral fluid codeine concentrations from the clinical study, the elimination rate constant, t(1/2), AUC and the peak oral fluid concentrations demonstrated device differences. The slope of the elimination curve for codeine using the acidic collection method exceeded that of the other four methods. As a result, the t(1/2) for the acidic method was significantly less than that of the control method (1.8 vs. 3.0 h, respectively). Oral contamination contributed to the control method having higher AUC than that calculated using the other methods. There was considerable variation in peak codeine concentrations between devices and between individuals within each collection method. When samples were collected simultaneously with the Salivette and the Finger Collector, the mean codeine concentrations were similar. We were able to recover > or = 500 microL of oral fluid from 81.8% of the clinical samples collected with the Salivette. However, we were able to recover this volume from only 25.5% of the samples collected with the Finger Collector. In addition, the in vitro drug recoveries were lower using the Finger Collector. When oral fluid was collected nearly simultaneously by the control method and by use of the Salivette, mean control codeine concentrations were 2.3 times higher, but the duration of detection was similar for both methods.

Suction methods for assessing contamination on surfaces

Suction sampling techniques are widely used to assess particulate contamination levels on domestic and occupational surfaces such as floor coverings, but their use for dermal exposure assessment has, to date, been limited. This paper reviews the sampling techniques commonly employed and summarises the range of sampling efficiencies reported in the literature. As there are an extremely large number of key factors influencing the recovery efficiency of suction sampling devices, it is recommended that controlled experiments are carried out to evaluate the relative significance of these factors, thus allowing inter-comparison of the data generated in field studies. As the range of applications of suction sampling devices is extensive, the harmonisation of sampling protocols is not considered to be a feasible objective.

NO(x) contamination in laboratory ware and effect of countermeasures

Contamination of various types of laboratory wares with NO(x) (NO(-)(2) and NO(-)(3)) was assessed systematically and the effect of extensive washing as a countermeasure was evaluated. Mean NO(x) contamination arising from a model procedure for NO(x) determination in plasma was 0.93 microM (range, 0.35-1.49 microM). The major source of contamination included conical tubes (54.8%) and pipette tips used for transfer of solution (12.3-16.3%). Except for soft glassware, most NO(x) contamination could be washed out by pure water. Although NO(x) contamination in respective laboratory wares could be reduced below detection levels by extensive washing, summation of the contamination through the model procedure could not be completely abolished (but the effect of washing persisted at least 10 days). Heavy contamination was noted in glassware (especially soft glass) and ultrafiltration units, which was difficult to remove. Several types of vacuum blood sampling tubes contained various levels of NO(x). Our results indicated that a small but significant amount of contamination remained in laboratory ware even after extensive washing, and that it is advisable to avoid the use of glassware (soft glass), ultrafiltration units, and vacuum blood sampling tubes during the processing of clinical sampling for the measurement of NO(x).

[Advances in the clinical laboratory automation system of Akita University Hospital]

Abstract Clinical laboratory automation, which was widely discussed in the 1960's, was developed in late he 1970's. The computerized automatic analyzing system for clinical laboratories spread nationwide in the 1980's. Akita University Hospital was established in 1971. We have been making efforts to establish the automated clinical laboratory system. The hematological and clinical chemistry divisions were automated in 1981. In 1988, in order to establish a fully automated clinical laboratory, we introduced sample-conveying systems in each division including hematological, clinical chemistry, urinalysis, serological and immunological divisions. In 1998, we connected the sample-conveying systems which had been separately established in each division to create a fully automated clinical laboratory with an integrated sample-conveying system.

[The diagnostic value of endometrial sampling with Endorette]

The usefulness of Medscand Endorette endometrial sampling was evaluated. The analysis was based on 142 cases with medical indications for endometrial biopsy. 122 women were successfully sampled. Only in 9 cases (6.3%) the collected endometrium was insufficient. Medscand Endorette seems to be a useful tool for the collection of endometrial samples, mainly in outpatients.

Chemokine RANTES in gingival crevicular fluid of adult patients with periodontitis

BACKGROUND, AIMS

This study presents the first evidence on the presence of the chemokine RANTES in the gingival fluid crevicular (GCF) of patients with periodontitis. RANTES is a chemokine that selectively attracts and activates macrophages and lymphocytes. Leucocytes play a critical rôle in the host response to the subgingival microflora.

METHOD

In this study, the presence de RANTES in GCF was determined in samples obtained from adult patients with periodontitis and from control subjects with clinically healthy gingiva. GCF was collected from different probing depths (<3 mm, 4-6 mm, >6 mm) (n = 72); and active (n = 12) and inactive sites (n = 12). An active site was defined as attachment loss >2 mm, as determined by sequential probing and the tolerance method. GFC was collected for 30 s using Periopaper strips, and RANTES was quantified by ELISA.

RESULTS

The presence of RANTES was detected exclusively in the group of patients with periodontitis, presenting a total amount of 40.43+/-16 pg and a concentration 67.80+/-41 pg/microl. RANTES concentration was significantly higher in probing depth <3 mm than in probing depth >6 mm (87.24 versus 51.87, p = 0.014). Total amount and concentration in the GCF samples from active sites were higher that in inactive sites (p>0.05).

CONCLUSIONS

The finding that RANTES is found only in patients with periodontitis, may represent a general feature of chronic inflammatory in periodontal diseases. Finally, RANTES may be implicated in the biological mechanisms underlying the pathogenesis and progression of periodontal disease.

Assessment of two devices for in vitro preparation of human sperm

The aim of the study was to assess and compare the efficiency of the ZSC-II versus the Sperm Select techniques in preparing human sperm from normozoospermic patients for use in intrauterine insemination and other assisted reproductive technologies. Twenty-five patients were included in the study. Semen was collected at intercourse and processed via 2 sperm preparation methods. Recovery of motile sperm and other sperm qualitative measurements were evaluated before and after ZSC-II and Sperm Select sperm preparation. Sperm qualitative measurements were not significantly different after the ZSC-II and Sperm Select procedures (p > .05). Differences (p < .05) were noted between the 2 procedures in the number of sperm recovered. A higher survival rate (longevity test, 72 h) was observed after ZSC-II sperm preparation and recovery. The ZSC-II procedure yielded higher total motile sperm than the Sperm Select. The superiority in longevity may suggest possible advantages in obtaining higher fertilization and pregnancy rates.

[The sampling of plaque specimens in oral microbiology]

Sampling is the first and most important step in the bacterial analysis of periodontal or endodontal infections. Sterile paperpoints are the ultimate tool to perform the sampling. Sampling is preferably done under continuous CO2-flushing, to preserve an anaerobic environment for the bacteria. For the dilution and the transport of the bacteria, Reduced Transport Fluid (RTF) is the most reliable fluid, when culturing is indicated. In all other cases, sterile physiologic water is sufficient.

Throat swab in the chronic tonsillitis: how reliable and valid is it?

INTRODUCTION

The diagnostic test of swabbing the surface of the tonsil as a culture specimen for the determination of the organism responsible for the tonsil infection is still in practice, despite controversy. To date there has been no reports of establishing the reliability and validity of this common diagnostic test by appropriate statistical test of Likelihood ratios taking into consideration the specificity and sensitivity.

AIMS

To assess the reliability and validity of throat swab in the diagnosis of bacterial microflora in chronic tonsillitis.

PATIENTS AND METHODS

A prospective study of 40 patients clinically diagnosed to have chronic tonsillitis undergoing tonsillectomy was undertaken. The reliability of the throat surface swab was then assessed and validated with the reference (gold) standard of tonsil core culture.

RESULTS

The likelihood ratio of this diagnostic test being positive (LR +ve) was 0.84 to similar and 1.3 to general organism pathogen.

CONCLUSION

Routine culture of the throat by surface swab in the accurate diagnosis of bacterial flora in chronic tonsillitis is neither reliable nor valid. The clinical implications of this investigation which is still very popular is discussed.

Lactate dehydrogenase activity in pathological human tears obtained with glass capillaries correlates with the albumin content

Lactate dehydrogenase (LDH) activity was measured in stimulated normal human tears and in tears from patients suffering from various corneal and conjunctival disorders. In normal tears the LDH activity was below the detection level of the method used, and it was hardly detectable in tears of most of the patients. The LDH activity correlated with the serum albumin content (r = 0.745, n = 32), suggesting that its source in pathological cases could be the plasma by transudation, and not the surface epithelial cells. Based on these results, LDH activity cannot be used as a measure of epithelial cell destruction in most pathological conditions, since the tear secretion of the patients is usually stimulated due to irritation, associated with the disorder or disease.

Improvement in transfusion safety using a specially designed transfusion wristband

Fatal haemolytic transfusion reaction due to ABO incompatibility occurs mainly as a result of clerical error. A blood sample drawn from the wrong patient and labelled as another patient's will not be detected by the blood bank unless there is a previous ABO grouping result. We report here the detection of such clerical error by the use of a specially designed transfusion wristband. The wristband has the following special features: (i) once attached, it cannot be removed except by cutting; (ii) it has a pocket containing a transfusion label; (iii) a unique transfusion barcode is printed on each transfusion label and the corresponding wristband simultaneously by computer technology; (iv) a transfusion label removed from the wristband after attachment to the patient has a characteristic tear-mark distinguishing it from one removed prior to attachment. The blood bank only accepted those specimens bearing the tear-marked transfusion labels. All blood units for this patient were labelled with this unique transfusion code together with the patient's details. The nurses counter-checked the transfusion code on the blood units against the transfusion code on the patient's transfusion wristband prior to transfusion. If the blood sample for compatibility testing was drawn from the 'wrong' patient, the intended patient either did not carry a wristband or the transfusion codes did not match at all. Pretransfusion compatibility tests were performed on 2189 patient samples using this procedure. It was well accepted by both ward and blood bank staff. Two potential mismatched transfusions were avoided. These two clerical errors would not have been detected because neither patient had previous ABO grouping results.

The BCSH guideline on addressograph labels: experience at a cardiothoracic unit and findings of a telephone survey

In 1998 we implemented a BCSH recommendation that addressograph labels should not be used on blood transfusion specimen tubes. Over a 12-month period before the ban was introduced our laboratory received 5964 red cell transfusion requests, 182 (3.1%) of which contained an error in the identification details (ID) supplied on the request form and/or specimen. Three of these errors were of the 'wrong patient' type, i.e. the sample belonged to a different patient from the one whose ID appeared on the specimen tube and request form. Over the 12 months after the ban was introduced 511 (8. 1%) of 6326 requests contained a labelling error, an increase in error rate of 165%; no wrong-patient errors were identified, however. In a survey, seven (29.2%) of 24 transfusion laboratories in the UK accepted specimens labelled with addressograph stickers; in four of these cases a local blood transfusion committee had agreed that the BCSH guideline should not be followed. We believe the BCSH guideline is valid; its implementation, however, has major financial and workload implications, which probably explains why many hospitals apparently do not comply with it.

Reverse transcription of an RNA genome from databasing paper (FTA(R))

The instability of RNA in solutions during storage and travel is an impediment to its utilization in routine diagnostics. A robust and simple approach to the problem of RNA protection and processing is offered by storage of RNA desiccated with processing procedures that do not solublize the RNA until the beginning of reverse transcription. The feasibility of this general approach was tested with coxsackievirus B4 (CVB-4) from blood or culture fluid held on a storage and transport medium (FTA(R)) and analysed by reverse transcriptase PCR (RT-PCR) without removing the RNA from the FTA(R) until reverse transcription. Phase-trapping techniques based on water-miscible solvents such as ethanol or phenol were compared with simple buffers and concentrated lithium chloride solutions. RT-PCR detection of viral RNA reached a sensitivity of approximately 0.1 fg, which is comparable with other non-nested PCR techniques. Whole blood as a virus vehicle significantly interfered with CVB-4 detection, but to an acceptable degree. Desiccation-storage of the RNA of CVB-4 appears to be unaffected by weeks on the storage medium under ambient conditions. These characteristics indicate that this approach forms a credible developmental base for RNA-based pathogen diagnostics with particular application to the problem of transporting potentially infectious body fluids to a centralized laboratory for analysis.

Blood culture bottles for transportation and recovery of anaerobic bacteria from non-blood samples

Using bacterial suspensions as simulated non-blood specimens, the capacity of three different BacT/ Alert blood culture bottles for the transportation and recovery of anaerobic bacteria with different sensitivity to air was evaluated. To better assess the performance of the BacT/Alert bottles, three other liquid media specially designed for anaerobes were included in the study. Attention was paid to recovery rates in relation to species, initial bacterial concentration, and time needed for detection. Of the BacT/Alert blood culture bottles, the anaerobic FAN bottle yielded the highest recovery rates, but its performance was limited compared with chopped meat broth in tubes. This broth allowed detection of all the tested species within 48 h. Since collection and transportation of anaerobic bacteria are of major importance for a reliable culture result, improvements are necessary.

[Contrast test using three kinds of air-microorganism samplers LWC-I, CA6 and CA2 in public places]

A sampling experiment was conducted using three kinds of air-samplers, i.e. LWC-1, CA6 and CA2, on bacteria and fungus in the air under the same conditions and at the same time yet in three different public places. The results showed that there was no significant difference in the total number of bacteria and fungus colony forming units in the air in different public places using the above mentioned three air-samplers. In comparison, the LWC-1 air-sampler demonstrated a feature of small size, light weight, simple structure, and little noise, therefore, it was easy in carrying and requires no external power source. Such being the case, the LWC-1 air-sampler was more suitable for monitoring microorganism in the air in public places.

Stand-alone automated solutions can enhance laboratory operations

Clinical laboratory automation has developed over the past decade as one means of consolidating testing, reducing costs, and improving the effectiveness of laboratory testing. Most of the developments have been aimed at core clinical laboratory operations, and have primarily addressed preanalytical and analytical processing of traditional specimens arriving in blood collection or similar aliquot tubes. Much less attention has been given to specialized applications such as processing specimens for urine toxicology, and only recently have vendors attacked the problems associated with sorting and maintaining the laboratory's inventory of specimens. This report highlights selected developments in these areas, describes one approach to cost-effective custom platform development, and discusses the advantages and pitfalls to solving problems with laboratory automation.

Hematology and pathology devices; reclassification; restricted devices; OTC test sample collection systems for drugs of abuse testing. Food and Drug Administration, HHS. Final rule

The Food and Drug Administration (FDA) is reclassifying over-the-counter (OTC) test sample collection systems for drugs of abuse testing from class III (premarket approval) into class I (general controls) and exempting them from premarket notification (510(k)) and current good manufacturing practice (CGMP) requirements. FDA is also designating OTC test sample collection systems for drugs of abuse testing as restricted devices under the Federal Food, Drug, and Cosmetic Act (the act) and establishing restrictions intended to assure consumers that: The underlying laboratory test(s) are accurate and reliable; the laboratory performing the test(s) has adequate expertise and competency; and the product has adequate labeling and methods of communicating test results to consumers. Finally, FDA is adding a conforming amendment to the existing classification regulation for specimen transport and storage containers to clarify that it does not apply to specimen transport and storage containers that are part of an OTC test sample collection system for the purpose of testing for the presence of drugs of abuse or their metabolites in a laboratory.