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PubMedDate not supplied

Cardiovascular recovery from acute laboratory stress: reliability and concurrent validity.

OBJECTIVE: We assessed the value of laboratory measures of cardiovascular recovery across four criteria: reliability across multiple tasks, reliability across a 3-year time interval, ability to predict daily ambulatory blood pressure, and interrelationships with coronary risk factors and psychosocial variables. METHODS: Three hundred twenty-nine healthy adults (mean age = 27.1 years) completed a two-part protocol consisting of 1 day of laboratory testing and 1 day of ambulatory monitoring. The laboratory protocol included a 15-minute baseline assessment followed by three 5-minute laboratory challenges (mental arithmetic, speech, and handgrip). Five-minute recovery periods followed each exercise. One hundred twenty-five participants returned after 3 years to repeat the protocol. RESULTS: When aggregated across tasks, cardiovascular recovery showed acceptable levels of internal consistency (alpha values = 0.7) and proved relatively stable across time (r values = 0.22-0.35). Recovery values statistically improved the prediction of daily ambulatory readings above baseline and stress reactivity laboratory values (p values < .001) but were largely unrelated to coronary risk factors or psychosocial measures. CONCLUSION: These results suggest that cardiovascular recovery from acute laboratory stress can be treated as a stable individual difference variable that can -improve standard laboratory-based predictor models of ambulatory readings.

Acute Disease↗
PubMed2007

Testing for sexually transmitted diseases in U.S. Public health laboratories in 2004.

OBJECTIVE: Appropriate laboratory testing practices are a critical part of sexually transmitted disease (STD) control. GOAL: The goal of this study was to describe the type and volume of STD tests performed in public health laboratories in the United States in 2004. STUDY DESIGN: A web-based survey was made available to 144 members of the Association of Public Health Laboratories. RESULTS: One hundred fourteen laboratories responded (79%). Overall, 3,553,196 chlamydia tests and 3,461,151 gonorrhea tests were performed; 64.4% of chlamydia tests and 60.8% of gonorrhea tests were nucleic acid amplification tests. Ninety-four percent of laboratories performed syphilis testing. Few laboratories used type-specific tests for herpes simplex virus or used new tests for trichomoniasis, bacterial vaginosis, or human papillomavirus. CONCLUSIONS: This survey collected important data that can be used to monitor trends in STD testing practices in public health laboratories.

Diagnostic Tests, Routine↗
PubMed2006

Microbial aerosol generation during laboratory accidents and subsequent risk assessment.

AIM: To quantify microbial aerosols generated by a series of laboratory accidents and to use these data in risk assessment. METHODS AND RESULTS: A series of laboratory accident scenarios have been devised and the microbial aerosol generated by them has been measured using a range of microbial air samplers. The accident scenarios generating the highest aerosol concentrations were, dropping a fungal plate, dropping a large bottle, centrifuge rotor leaks and a blocked syringe filter. Many of these accidents generated low particle size aerosols, which would be inhaled into the lungs of any exposed laboratory staff. Spray factors (SFs) have been calculated using the results of these experiments as an indicator of the potential for accidents to generate microbial aerosols. Model risk assessments have been described using the SF data. CONCLUSIONS: Quantitative risk assessment of laboratory accidents can provide data that can aid the design of containment laboratories and the response to laboratory accidents. SIGNIFICANCE AND IMPACT OF THE STUDY: A methodology has been described and supporting data provided to allow microbiological safety officers to carry out quantitative risk assessment of laboratory accidents.

Accidents, Occupational↗
PubMed2001

The dental student as a technician: preclinical and clinical laboratory programs in fixed prosthodontics.

PURPOSE: A 2-part survey of United States dental schools was conducted. The first part of the survey was published in 1998 and determined the curricular structure, techniques taught, and materials used in predoctoral fixed prosthodontics courses. The purpose of the second part of the survey was to ascertain the delegation of laboratory procedures in preclinical and clinical fixed prosthodontic programs. MATERIALS AND METHODS: The survey was mailed to the course directors of predoctoral fixed prosthodontic programs at 53 US dental schools. Of these, 42 schools returned the completed survey, resulting in a response rate of 79%. RESULTS: Results from this survey show that certain laboratory procedures in preclinical and clinical fixed prosthodontics are completed by dental laboratories (either in-house or commercially available laboratories). CONCLUSIONS: For the preclinical programs of fixed prosthodontics, there is more student involvement in the completion of laboratory procedures in the dental schools surveyed. In clinical fixed prosthodontic programs, there is a high emphasis on patient care and less on laboratory techniques that can be delegated to laboratory technicians.

Crowns↗
PubMed1999

Analysis of charges and complications of permanent pacemaker implantation in the cardiac catheterization laboratory versus the operating room.

During the last two decades, an increasing number of permanent pacemakers have been implanted outside of the operating room (OR) by nonsurgeons. Previous investigators have demonstrated that pacemakers can be safely implanted in the cardiac catheterization laboratory with no increase in complications or infections. This is the first study of its kind to simultaneously evaluate cost, length of hospitalization, and complications between pacemakers implanted in the OR by surgeons with those implanted in the catheterization laboratory by an electrophysiologist. A total of 254 consecutive pacemaker implants were analyzed over a 2-year period. The OR group consisted of 122 patients with a mean age of 64 +/- 21 years versus 132 patients in the catheterization laboratory group with a mean age of 65 +/- 17 years. The indication and type of pacemaker implanted were similar among both groups with 78% of OR patients and 73% of catheterization laboratory patients receiving dual chamber devices. The average cost for pacemaker implantation in our study was significantly higher in the OR group $5,464 +/- $1,670 versus $2,682 +/- $8 for the catheterization laboratory group (P < 0.001). There was a reduction in preimplant days in the catheterization laboratory group 3.16 +/- 12.40 days versus 5.65 +/- 9.54 days in the OR group (P < 0.05). Complications were minimal and there were no significant differences between the two groups. This study confirms that pacemakers can be safely implanted in the catheterization laboratory by nonsurgeons with no increase in complications and a significant reduction in hospital costs.

Aged↗
PubMed1979

Microbiology subsystem of a total, dedicated laboratory computer system.

The computer system used by the Microbiology Service of the Clinical Pathology Department, Clinical Center, National Institutes of Health is discussed. This microbiology subsystem is a part of a dedicated on-line laboratory computer system used by the entire department. The laboratory computer is connected on-line to a hospital computer which provides patient admission, transfer, and discharge data. Mark sense worksheets and cathode ray tube terminals are used for result entry and correction. Cumulative patient reports are printed. Results for both active and completed accessions can be easily retrieved on cathode ray terminals in the laboratory. All laboratory data are archived on magnetic tape from which a research data base and microfiched laboratory records are generated. The manner in which the system is integrated in the routine operation of the microbiology laboratory is emphasized. In addition, some of the costs, benefits, liabilities, and pitfalls associated with the introduction of the computer in the laboratory are reviewed. Finally, we have presented our concept of some of the future enhancements to our present system and some of the directions in which any future microbiology system might develop.

Computers↗
PubMed1985

Infections acquired in clinical laboratories in Utah.

We reviewed laboratory-acquired infections occurring in Utah from 1978 through 1982. Written and telephone interviews of supervisors of 1,191 laboratorians revealed an estimated annual incidence of 3 laboratory-acquired infections per 1,000 employees. Infections, in order of frequency, included hepatitis B (clinical cases), shigellosis, pharyngitis, cellulitis, tuberculosis (skin test conversion), conjunctivitis, and non-A, non-B hepatitis. One-half of large laboratories (over 25 employees), but only 12% of smaller laboratories, reported infections. The annual incidence, however, at smaller laboratories was more than three times greater than at large laboratories (5.0 versus 1.5 per 1,000; P less than 0.05, chi-square test). Microbiologists were at greatest risk of infection, with an incidence of almost 1%, followed by generalists and phlebotomists. Shigellosis was acquired only by microbiologists and accounted for more than half of their infections. The most common laboratory-acquired infection, hepatitis B, affected a microbiologist, a hematologist, a phlebotomist, a pulmonary blood gas technician, and a blood bank technologist who died from her illness. Clinical cases of hepatitis B occurred at a rate 10 times higher than the rate in the general U.S. population. The incidence of tuberculosis skin test conversion was intermediate between rates reported for hospital employees and for the state of Utah.

Aerosols↗
PubMed1986

Relationship between performance in three of the Centers for Disease Control microbiology proficiency testing programs and the number of actual patient specimens tested by participating laboratories.

The performance of laboratories enrolled in three of the Centers for Disease Control microbiology performance evaluation programs was studied in relation to the number of actual patient specimens tested by the laboratories. Laboratories were grouped according to the number of specimens tested weekly to compare performance among the groups. Results of the study showed that laboratories, as a group, that tested large numbers of specimens performed better than laboratories that tested small numbers. The infrequency of performing certain tests or identifying certain microbial species can be an important factor in laboratory error. One strategy for laboratories that cannot resolve internal problems associated with low testing volumes would be to limit their testing to procedures that are done well.

Bacteriology↗
PubMed2005

External quality assessment for molecular detection of Bordetella pertussis in European laboratories.

Although the PCR for the detection of Bordetella pertussis is routinely performed in diagnostic laboratories, no quality assessment program has so far been described. We report on the results obtained with two external quality assessment proficiency panels sent to European laboratories. The first proficiency panel contained a series of dilutions of three previously characterized B. pertussis clinical isolates and two negative controls. No false-positive results were reported by six laboratories providing seven data sets. The reported limits of detection of the three B. pertussis strains varied between 4 and 4,000, 9 and 9,000, and 3 and 30,000 CFU/ml, respectively. The second proficiency panel, composed of a series of dilutions of reference strains of B. pertussis, B. holmesii, B. hinzii, and B. bronchiseptica, as well as negative controls, was sent to nine laboratories. One laboratory reported a negative result for a sample and reported a B. parapertussis-positive sample to be positive for B. pertussis. By using the B. pertussis-specific target gene pertactin, one laboratory detected B. pertussis with 100% specificity. All other laboratories, which used IS481-based assays, reported positive results for the samples containing B. holmesii and B. bronchiseptica, species that have occasionally been recovered from human respiratory samples. These data show that the choice of the target gene is particularly critical for the species specificity of B. pertussis PCR assays.

Bordetella pertussis↗
PubMed1992

Laboratory examination for Cryptosporidium spp in Scotland.

AIMS: To ascertain the present practices of Scottish microbiological laboratories for examining faecal samples for Cryptosporidium spp and to compare these with practices elsewhere. METHOD: A questionnaire was circulated to all 35 Scottish NHS bacteriological laboratories, where human stool samples are subjected to routine microbiological examination, to determine current laboratory testing methods and selection criteria used to examine faecal specimens for Cryptosporidium spp. RESULTS: All laboratories responded, of which the first began testing in 1984 and the last in 1990. At 15 sites all diagnostic stool samples submitted are routinely examined for Cryptosporidium spp. Elsewhere, selection criteria, principally based on age, specific request, and foreign travel, are used. The age distribution of Scottish cases differed significantly from that of the PHLS study of 16 laboratories (p < 0.001), probably as a result of the selection criteria used. The phenol-auramine staining procedure is used by 19 laboratories, with modified Ziehl-Neelsen staining used by 14 laboratories; eight used a second, confirmatory method. CONCLUSIONS: Currently applied selection criteria for examination of stools for Cryptosporidium in Scotland do not accord with published epidemiological data. Specimen selection based on age of patient and stool consistency may lead to cases of public health importance being missed. Nationally agreed criteria for testing of human samples based on epidemiological evidence are required.

Adolescent↗
PubMed1995

Internal audit in a microbiology laboratory.

AIM: To set up a programme of internal laboratory audit in a medical microbiology laboratory. METHODS: A model of laboratory based process audit is described. Laboratory activities were examined in turn by specimen type. Standards were set using laboratory standard operating procedures; practice was observed using a purpose designed questionnaire and the data were analysed by computer; performance was assessed at laboratory audit meetings; and the audit circle was closed by re-auditing topics after an interval. RESULTS: Improvements in performance scores (objective measures) and in staff morale (subjective impression) were observed. CONCLUSIONS: This model of process audit could be applied, with amendments to take local practice into account, in any microbiology laboratory.

Humans↗
PubMed1999

Is the international normalised ratio (INR) reliable? A trial of comparative measurements in hospital laboratory and primary care settings.

AIM: To determine the reliability of international normalised ratio (INR) measurement in primary care by practice nurses using near patient testing (NPT), in comparison with results obtained within hospital laboratories by varied methods. METHODS: As part of an MRC funded study into primary care oral anticoagulation management, INR measurements obtained in general practice were validated against values on the same samples obtained in hospital laboratories. A prospective comparative trial was undertaken between three hospital laboratories and nine general practices. All patients attending general practice based anticoagulant clinics had parallel INR estimations performed in general practice and in a hospital laboratory. RESULTS: 405 tests were performed. Comparison between results obtained in the practices and those in the reference hospital laboratory (gold standard), which used the same method of testing for INR, showed a correlation coefficient of 0.96. Correlation coefficients comparing the results with the various standard laboratory techniques ranged from 0.86 to 0.92. It was estimated that up to 53% of tests would have resulted in clinically significant differences (change in warfarin dose) depending upon the site and method of testing. The practice derived results showed a positive bias ranging from 0.28 to 1.55, depending upon the site and method of testing. CONCLUSIONS: No technical problems associated with INR testing within primary care were uncovered. Discrepant INR results are as problematic in hospital settings as they are in primary care. These data highlight the failings of the INR to standardise when different techniques and reagents are used, an issue which needs to be resolved. For primary care to become more involved in therapeutic oral anticoagulation monitoring, close links are needed between hospital laboratories and practices, particularly with regard to training and quality assurance.

Anticoagulants↗
PubMed2006

Laboratory work and pregnancy outcomes: a study within the National Birth Cohort in Denmark.

AIMS: To examine pregnancy outcomes in women doing laboratory work. METHODS: Using data from the Danish National Birth Cohort (1997-2003), the authors conducted a prospective cohort study of 1025 female laboratory technicians and 8037 female teachers (as reference). The laboratory technicians were asked about laboratory work tasks during pregnancy in an interview (at around 16 weeks of gestation). Pregnancy outcomes were obtained by linking the cohort to the national registers. Hazard ratios (HRs) of late fetal loss and diagnosing of congenital malformations were calculated by using Cox regression, and odds ratios (ORs) of preterm birth and small for gestational age were calculated by using logistic regression. RESULTS: Overall, there were no significant differences in pregnancy outcomes between laboratory technicians and teachers. However, we found that laboratory technicians working with radioimmunoassay or radiolabelling had an increased risk of preterm birth (OR = 2.2, 95% CI 0.8 to 6.2 for radioimmunoassay, and OR = 1.9, 95% CI 0.8 to 4.6 for radiolabelling) and "major" malformations (HR = 2.1, 95% CI 1.0 to 4.7 for radioimmunoassay, and HR = 1.8, 95% CI 0.9 to 3.7 for radiolabelling). The ORs of preterm birth doubled for women working with these tasks every day or several times a week. When an exposure matrix was applied, an increased risk of "major" malformations for exposure to organic solvents was seen. CONCLUSIONS: The results did not indicate any high risk of reproductive failures in laboratory technicians in general. Exposure to radioisotopes may carry a high risk of preterm birth and congenital malformations. This finding deserves further investigation.

Adult↗
PubMed1996

Local cold exposure of the hands from cryosectioning work in histopathological and toxicological laboratories: signs and symptoms of peripheral neuropathy and Raynaud's phenomenon.

OBJECTIVES: To study relations between cryosectioning work, skin temperature, early signs of neuropathy in the hands, and vasospastic and neurological symptoms. Microtome work is carried out at histological and toxicological laboratories all over the world. It implicates local cold exposure of -20 degrees C on the hands of exposed laboratory technicians. METHODS: Thirty nine laboratory technicians who use microtomes at the preclinical and clinical laboratories at the University of Uppsala, Sweden were studied. An equal number of nonexposed laboratory technicians served as controls, matched for workplace, sex, age, and smoking habits. Information on symptoms, type of work, and personal factors were assessed by means of a self administered questionnaire. Two point discrimination ability was tested, and vibration perception threshholds were measured for both hands by a bio-thesiometer. Also, skin temperature was measured during cryosectioning work in those 15 technicians performing cryosectioning work during the study period. RESULTS: Most laboratory technicians did not use any gloves during cryosectioning work, and direct contact with frozen materials sometimes occurred and resulted in a rapid cooling of the skin. In six of 15 exposed subjects (40%), the mean skin temperature during microtome work was below 20 degrees C. A later rise in skin temperature, due to a compensatory vasodilation, was found in two subjects. The group exposed to cold had signs of early neuropathy on the right hand, indicated both by vibrametry and two point discrimination test. Significant work related differences in clinical signs within the group exposed to cold was also found. No differences between exposed and nonexposed people were found for symptoms of Raynaud's phenomenon, numbness, or musculosceletal complaints. CONCLUSION: Our study shows that cryosectioning laboratory work may cause adverse health effects--for example, peripheral neuropathy--and measures should be taken to protect the hands from the local cold exposure.

Adult↗
PubMed1992

Auditing quality control procedures in a chemical pathology laboratory--a multiple regression analysis.

We undertook a retrospective analysis of the monthly test rejection rates and the monthly external quality assessment scheme performance indices for our laboratory's two automated analysers, and examined the association of these variables with measures of laboratory workload, manpower, staff training, instrument servicing, seasonal and temporal factors and changes of calibration, method and assigned internal quality control values. Using multiple linear regression and stepwise multiple linear regression, we found that test rejection rates differed significantly between instruments, and were highest on the instrument performing the widest variety and lowest volume of tests. On that instrument, rejection rates were significantly associated with the introduction of new staff and laboratory manpower levels, and also showed a highly significant trend upwards over the study period, independent of the effects of the other variables examined. External quality assessment scheme performance indices showed small trends over the study period. They were not related to the test rejection rates on either analyser but also showed a significant association with the introduction of new staff and a small but significant association with laboratory workload. We conclude that the training and introduction of new staff and decreased laboratory manpower levels may significantly increase the level of test rejection, and adherence to appropriate quality control protocols effectively maintains the quality of the laboratory's results, but may not be completely successful in filtering out the effects of some assignable causes of variation in test results. It is suggested that clinical laboratories use the statistical approach adopted here to identify factors which may be adversely affecting quality performance and running costs and to provide evidence that quality control procedures are both cost- and quality-effective.

Clinical Laboratory Techniques↗
PubMed1996

Adjustment of serum total calcium for albumin concentration: effects of non-linearity and of regression differences between laboratories.

It has been reported that the relationship between serum total calcium and albumin concentrations in hospital patients deviates from linearity at low albumin concentrations. We searched a large laboratory computer data base for adult patients with discretionary requests for serum calcium analysis but with no other data suggestive of disturbances of calcium homeostasis, and collected a minimum of 100 calcium values at each of a wide range of albumin concentrations. We confirmed the earlier observation, but found that the use of a single regression to derive an adjustment of total calcium for albumin gave only small differences of no clinical significance. To investigate whether equations to adjust total calcium for albumin can be transferred between laboratories, three laboratory computers were searched for calcium requests from patients likely to have a low prevalence of calcium disturbances. The regressions of total calcium on albumin differed significantly between laboratories, but within each laboratory gave adjusted calcium values identical with those in health. Although the errors resulting from applying an equation from one laboratory to another were small and unlikely to be of major clinical significance, we recommend that where possible laboratories should derive adjustment equations from their own data.

Adult↗
PubMed1993

Reproducibility of a commercial enzyme-linked immunosorbent assay for bovine paratuberculosis among eight laboratories.

Interlaboratory reproducibility of an absorbed enzyme-linked immunosorbent assay (ELISA) kit for detection of bovine serum antibodies to Mycobacterium paratuberculosis was evaluated. A panel of 30 bovine sera (15 positives and 15 negatives) was tested in triplicate microtiter wells on each of 2 days at 8 different laboratories. One laboratory had invalid results because of positive or negative serum control optical density (OD) readings beyond the acceptable range specified by the kit. The coefficient of variation (CV) for mean OD values was influenced by low ODs on test negative sera at 2 laboratories, thus the CVs on positive sera were considered a more representative measure of kit reproducibility. Between-well CVs averaged 6.7% +/- 2.8% (mean +/- standard deviation), and between-day CVs averaged 14.5% +/- 9.8% among the 7 laboratories with valid assays on the 15 positive sera. The OD values were converted to positive or negative classifications for each assay well, and the results were compared. Among 1,392 assays in 7 laboratories, 98.6% were in agreement. Eleven of 18 discrepant results were due to a sample that consistently gave OD values near the cutoff for a positive test. Exclusion of that serum from the analysis resulted in a 99.8% rate of agreement among laboratories. Results indicated that the absorbed ELISA kit provided reproducible results within and between laboratories.

Analysis of Variance↗
PubMed2006

Integration of local and central laboratory functions in a worldwide multicentre study: Experience from the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Study.

BACKGROUND: Measurement of glucose in multiple Field Laboratories requires rigorous standardization when patients and caregivers are masked, unless predefined thresholds are met. Local misclassification of participants at the thresholds can introduce recruitment bias and adversely affect the integrity of study findings. PURPOSE: To describe the challenges and the approach to meeting them in measuring glucose, HbA1c, and C-peptide in the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) Study. HAPO is an observational epidemiologic study of 25 000 pregnant women from 15 centres in 10 countries, designed to clarify unanswered questions on associations of maternal glycemia, less severe than overt diabetes mellitus, with risks of adverse pregnancy outcome. METHODS: Glucose tolerance (75 g two-hour OGTT) is assessed locally at 24-32 weeks' gestation, with results masked if fasting and two-hour plasma glucose are </=5.8 mmol/L and </=11.1 mmol/L, respectively. For analysis of outcomes HAPO utilizes measurements of glucose, C-peptide, and HbA1c on frozen samples in a Central Laboratory; measurement of HbA1c on stored, frozen blood also creates special challenges. A common external quality assessment scheme was used to standardize glucose measurements between Field Centre and Central Laboratories before and during data collection. RESULTS: Agreement between Field Centres and the Central Laboratory in rates above the masking thresholds has been excellent (Kappa = 0.79, P < 0.001), with rates of 1.8 and 1.7% respectively. Percent technical error for Central Laboratory OGTT measurements of glucose, C-peptide, and HbA1c, were 2.0, 4.2, and 2.0, respectively. LIMITATIONS: It is not possible to assess if comparable results could have been obtained with a less rigorous approach to standardization. CONCLUSIONS: HAPO has been successful in ensuring comparability of glucose measurement between its Central Laboratory and Field Centre laboratories and in measuring its key metabolites with accuracy and precision. Recruitment bias based on glucose measurement has been avoided.

Blood Glucose↗