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PubMed1984

A survey of genetic toxicology testing in industry, contract laboratories and government.

Genetic Toxicology Association members from governmental, contract and industrial laboratories were surveyed to determine the status of 28 recognized genetic toxicology assays in their laboratories. Compiled results of the 1982 questionnaire indicate that the Ames test, in vitro cytogenetics, in vitro sister chromatid exchange, unscheduled DNA synthesis, mutation in Chinese hamster ovary cells at the HGPRT locus, and in vivo bone marrow assays were the most frequently performed routine tests by the majority of laboratory affiliations. Investigation of the number of transformation assays performed indicated a high routine use. However, their use was largely confined to contract laboratories. Volume analysis of chemicals tested for 1982 indicated: (i) contract laboratories studied the largest number of compounds over the broadest spectrum of assays; (ii) industrial laboratories processed more compounds in the Ames test than any other laboratory group; and (iii) governmental laboratories ranked lowest in numbers of compounds evaluated both in-house and/or subcontracted .

Animals↗
PubMed2003

Inter-laboratory comparison of HCV-RNA assay results: implications for multi-centre research.

To investigate whether it is appropriate to assume comparability of hepatitis virus C (HCV)-RNA results across laboratories in multi-centre studies, nine laboratories of the European Paediatric HCV Network participated in an international proficiency study of HCV-RNA assays. A panel of 12 samples of different dilutions and genotypes was sent to each laboratory and tested with qualitative and/or quantitative HCV-RNA assays according to local procedures. Commercial assays were used in seven laboratories and in-house assays in two. All six laboratories in which a commercial qualitative assay was used were proficient, as were four of six runs (in five laboratories) in which a commercial quantitative assay was used. The proficiency of the laboratories where in-house assays were used could not be assessed according to the VQC definition because of differences in the methods used. Overall, there were several false-negative results, but only one false-positive result with a quantitative assay and none with a qualitative assay. The false-negative results may have implications for the diagnosis of infection, and highlight the need for an antibody test to be performed at 18 months to confirm the absence of infection. The results of qualitative assays were generally consistent across laboratories but it was difficult to evaluate and compare the results of quantitative assays. Multivariate analysis of data collected in multi-centre studies should therefore allow for centre and/or assay used.

Child, Preschool↗
PubMed2006

Factors influencing laboratory workers' decisions to accept or decline anthrax vaccine adsorbed (AVA): results of a decision-making study in CDC's anthrax vaccination program.

BACKGROUND: Laboratory technicians, laboratory supervisors, decontamination/remediation workers, and environmental investigators are at increased risk for repeated occupational exposure to Bacillus anthracis. In 2002, the Advisory Committee on Immunization Practices (ACIP) recommended pre-exposure vaccination for these occupational groups. OBJECTIVES: To determine (1) the factors that influenced an individual's decision to either accept or decline Anthrax Vaccine Adsorbed (AVA), and (2) if laboratory workers' concern about AVA safety was related to their information needs and trust in the information provided. METHODS: We conducted a decision-making survey of 404 participants at 44 Laboratory Response Network laboratories located throughout the United States. All participants were enrolled between October 2002 and December 2004, and all were eligible to receive AVA according to the 2002 ACIP recommendations. Chi-square tests and multivariate logistic regression were used in the analyses. RESULTS: The response rate of eligible individuals at participating laboratories was 94% (404/430). Sixty-six percent of respondents accepted and 34% declined AVA. Laboratory workers who declined AVA were more likely to rate their risk of exposure to inhalation anthrax as low (OR = 6.9; 95%CI 1.7, 28.3), report being very concerned (OR = 4.1; 95%CI 1.8, 9.3) or concerned (OR = 2.0; 95%CI 1.3, 3.1) about the safety of the vaccine, report that they did not trust the information provided in the Vaccine Information Statement (VIS) (OR = 2.3; 95%CI 1.1, 4.5), and to be enrolled in the study during 2002 (OR = 24.7; 95%CI 6.4, 95.3) or 2003 (OR = 5.0; 95%CI 2.5, 9.8), the first 2 years of the study. Furthermore, we found a significant association between a participant's level of concern about the safety of AVA and their perception that they received enough information and/or trusted the information in the VIS. CONCLUSIONS: Low perceived necessity, concern about the safety of the vaccine, and a lack of trust in the VIS were associated with the decision of laboratory workers to decline AVA. Results of this decision-making study may be used to try to improve acceptance rates of AVA among persons considered at high risk, and may inform educational efforts for other adult vaccines.

Adult↗
PubMed1977

A computerized approach to statistical quality control for radioimmunoassays in the clinical chemistry laboratory.

Methods for statistical quality control for the clinical laboratory in general, and radioimmunoassay in particular, have been proposed for many years. Unfortunately, only a very small number of laboratories have adapted these procedures. By use of teletypes and other remote terminals, it is possible for all laboratories to access centralized computers where a general purpose quality control program can be stored. This relieves each laboratory of the costly task of developing software, provides some degree of inter-laboratory standardization and facilitates comparison of precision and accuracy between laboratories. A prototype program for this purpose is described. This program evaluates within-assay and between-assay variability, by means of an analysis of variance for a one-way classification random-effects model, and can monitor any assay parameter by use of control chart techniques. In addition, several tests are provided to evaluate the temporal stability of the assay system, and appropriate tests for outliers are included. Also, methods are described for combination of information from several quality control samples. This provides a valid basis for adjustment of assay results or for outright rejection of an assay. For convenience, this program is designed for output on a teletype or similar terminal located in the laboratory. Simplified versions of this program can be readily adapted to desk-top calculators. The original purpose for developing this system was to provide the clinical laboratory with a simple, general, and flexible method for assessing the performance of radioimmunoassays, but its usefulness should extend to virtually all assay methods.

Computers↗
PubMed1991

The murine local lymph node assay: results of an inter-laboratory trial.

The local lymph node assay is a novel predictive test for the identification of contact allergens. The collaborative study reported here was performed to evaluate the reliability of the method when performed in independent laboratories. Eight chemicals were examined in each of 4 participating laboratories and results compared with predictions of skin-sensitizing activity made from concurrent Magnusson and Kligman guinea-pig maximization tests performed in a single laboratory. The local lymph node assay has as its theoretical basis the fact that contact allergens induce T-lymphocyte proliferative responses. In practice, predictions of contact-sensitizing potential are made following measurement of proliferation in lymph nodes draining the site of exposure to chemical, and derivation of a stimulation index using control values as the comparator. Although in the present study there was some variation between laboratories with respect to the absolute stimulation indices recorded, it was found that with all chemicals each laboratory made the same predictions of sensitizing activity. Six chemicals (2,4-dinitrochlorobenzene, formalin, eugenol, isoeugenol, p-phenylenediamine and potassium dichromate) yielded positive responses, and two (methyl salicylate and benzocaine) were negative, in each laboratory. Furthermore, with 7 of the 8 chemicals tested there was no significant difference between laboratories in terms of the characteristics of the dose-response relationships recorded. With the exception of one chemical (benzocaine), predictions made with the local lymph node assay were in accord with those derived from guinea-pig maximization tests. These inter-laboratory comparisons demonstrate that the local lymph node assay is a robust and reliable method for the identification of at least moderate and strong contact allergens.

Allergens↗
PubMed2004

Genomic biomarkers for cancer assessment: implementation challenges for laboratory practice.

Genomic biomarkers are an emerging class of laboratory tests, which present special implementation challenges for clinical laboratory services, compared to conventional laboratory tests. These challenges, which include analytical, bioinformatics, bioethical, interpretation and commercialization issues, represent real obstacles to widespread implementation of these tests. Technical challenges include the capacity to detect and identify many different kinds of markers for different diseases in a short time period, capacity to identify simultaneously gene rearrangements, amplification, inhibition, deletions and replications. Bioinformatics challenges include rapid analysis of genomic data, as well as the cross reference to other genomic data, and to other laboratory tests. Bioethical issues relate to consent to retain and use genetic data, which may be obtained inadvertently during analysis for genomic markers. Interpretation challenges include observations that the particular genomic markers may not be independent variables, as other undetected genomic alterations could invalidate or alter genomic marker interpretation. Further, as early experience with predictive genetic markers for cancer has shown, proprietary commercial interests may conflict with public health values of identifying genomic markers in subject populations. Based on our 10 years of experience with genomic biomarkers, important implementation strategies for genomic markers include development of:Standard high throughput analyzers capable of detecting any alteration of any genomic variant at any time. Bioinformatics analysis online, coupled to stored patient data. Laboratory service framework that preserves confidentiality but integrates genomic data with other laboratory tests. Laboratory service framework, which links consents, genomic analysis, reports to both specimen and data repositories. Overall, the laboratory service challenges for genomic markers are to manage very large analytical sets and very large data sets in finite time with responsible interpretation, all within finite funding. To meet these challenges, implementation strategies beyond the one disease, one diagnosis, one genomic marker concept must begin now.

Biomarkers, Tumor↗
PubMed2025

Impact of laboratory-driven proactive reanalysis: Reclassification to positive in 5% of initially negative or uncertain exome sequencing cases.

PURPOSE: Reanalysis of exome sequencing (ES) data increases diagnostic utility; however, there is no consensus on when and under what circumstances reanalysis should occur. Requesting and performing ES reanalysis burdens both clinical and laboratory workflows. Maximizing the potential for reclassification is essential. Here, we describe the impact of a laboratory-driven proactive reanalysis process that triggers reanalysis when new evidence is identified. METHODS: We reviewed reanalysis outcomes of an ES cohort. Reanalysis events were categorized based on initiating factors (laboratory-driven proactive, family studies, and clinician-initiated). Laboratory-driven proactive reclassifications are prompted by systematic review of new scientific data. Outcomes were evaluated by initiating factors, reclassification types, evidence used, and time since original report. RESULTS: Overall, 23% of cases underwent at least 1 reanalysis, with 35% of reanalyses resulting in reclassification. There was a 4% increase in diagnostic yield, including 5% of initially unsolved ES receiving diagnostic reports. Diagnostic reclassifications rates were significantly higher for laboratory-driven proactive reanalyses (54%; P < .0001) than family studies (18%) and clinician-initiated reanalyses (4%). New gene-disease relationships were the most efficacious evidence source. Laboratory-driven proactive reclassifications occurred steadily over time. CONCLUSION: Laboratory-driven proactive reanalysis effectively provides more diagnostic reclassifications compared with clinician-initiated reanalysis. Laboratories should curate and integrate emerging evidence into ES reanalysis.

Humans↗
PubMed2005

Implementation of the community network of reference laboratories for human influenza in Europe.

BACKGROUND: The increased need for accurate influenza laboratory surveillance data in the European Union required formalisation of the existing network of collaborating national influenza reference laboratories participating in the European Influenza Surveillance Scheme (EISS). OBJECTIVE: To establish a Community Network of Reference Laboratories for Human Influenza in Europe (CNRL). METHODS: Virologists in EISS defined the objective and tasks of the CNRL. Performance of the laboratories in the tasks was monitored by questionnaire-based inventories and quality control assessments (QCA). Subsequently, actions were defined to improve the performance of the CNRL. RESULTS: The CNRL started in April 2003 and included as of May 2004 32 laboratories in 24 European countries. The objective is to provide high quality reference services for human influenza surveillance, early warning and pandemic preparedness in Europe. The defined basic tasks are direct detection, culture, typing, subtyping and strain characterisation of influenza virus, diagnostic influenza serology and storage of clinical specimens and virus isolates. The questionnaire-based inventories and QCAs revealed that the majority of CNRL laboratories perform well in most of the basic tasks, although improvements are needed in certain areas of virus testing. Therefore, task groups have been established to further improve the methods used in the network. The CNRL has proven its usefulness during the 2003-2004 season by the reporting of accurate data concerning the flu epidemic caused by A/Fujian/411/2002 (H3N2)-like viruses and by the rapid sharing of information, protocols and reagents during the A(H5N1) and A(H7N3) epizootics in Asia and Canada. CONCLUSION: EISS has established a functioning Community Network of Reference Laboratories for Human Influenza in Europe and laid the foundation for further enhancement and collaborations. Important next steps include improving the laboratories to carry out all basic tasks and collaboration with the European Centre for Disease Prevention and Control.

Community Networks↗
PubMed2004

Animal laboratories for procedural education of emergency medicine residents.

Many Emergency Medicine residencies incorporate animal laboratories into their training for procedural education because clinical opportunities to practice some emergency technical procedures are limited. To determine the proportion of Emergency Medicine residency programs utilizing animal laboratories, their characteristics, and the major impediments to providing animal laboratories, a cross-sectional descriptive survey of Emergency Medicine residency directors was conducted. Surveys were returned by 109/123 (89%) program directors. Ninety-four (87%) programs provide live animal laboratories for procedural training, an increase from previous studies. Although only 28% of directors knew the cost of the laboratories, this was the most commonly listed impediment (66%) to providing them. In conclusion, the use of animal laboratories for procedural training in Emergency Medicine residencies has increased in recent years. Cost is reported to be the most significant impediment to providing animal laboratories. The majority of program directors do not know the actual expense of providing animal laboratories.

Animals↗
PubMed1998

Quality management in the medical laboratory: a comparison of draft standards.

Clinical laboratories used to rely almost completely on functional tests to monitor and assess their performance. This is known as internal quality control (IQC). A supporting approach is the interlaboratory comparison. In many countries and other disciplines this is known as proficiency testing, whereas, in Europe, the procedure is better known as external quality assessment taken care of by different schemes (EQAS). Probably all laboratories participate in some kind of EQAS and in some countries it is mandatory. It has gradually become apparent that functional tests are not sufficient to achieve, assure and develop quality in medical laboratories. Therefore other means must be sought. The principles laid down in the ISO 9000 series and the total quality concept has become interesting; in particular, accreditation. Accreditation of laboratories has been available for many years and in fact is routine in some specialities e.g. food, water laboratories and in some countries also for laboratories in the veterinary field. The present paper describes some features of the available and planned ISO standards that deal with accreditation of laboratories and particularly those adopted for the medical laboratories.

Accreditation↗
PubMed1999

The clinical importance of laboratory reasoning.

The radical changes made in the delivery of modern health care have serious implications for laboratory services, because reasoning in laboratory medicine should follow a clinical rather than a technological logic. Appropriate test requesting and interpretation coupled with a patient-oriented vision improve the outcomes for patients, and so ensure the best cost containment strategy. The fact that analytical operations are standardized and quality controlled, may lead to a greater recognition of the importance of pre- and post-analytical issues. Particularly critical aspects are the formulation of the clinical question and the interpretation of laboratory results. Laboratory-clinic communication is fundamental in achieving and maintaining total quality in laboratory services. Effective consultancy stands or falls with the knowledge and experience of laboratorians, as well as continuous education is required to maintain the best utilization of laboratory information in clinical decision-making. As clinical audit is an important tool for reviewing and improving the quality of the service in clinical laboratories, it should make up an important part of programs for accreditation and quality improvement. If a patient-centered vision predominates, the clinical laboratory will be linked to both physicians and patients, making it more tangible to the latter.

Cost Control↗
PubMed1986

The responsible use of the clinical laboratory.

Concern about spiralling health care costs is leading to a reexamination of the use of the clinical laboratory and other diagnostic technologies in patient care. Laboratory resources are viewed as limited and their use must be measured to meet real needs. Several observers have noted significant overutilization and inappropriate utilization of laboratory services by patient care physicians, especially at teaching hospitals. Efforts to modify physician behavior by use of educational programs, positive incentives and similar means have been largely disappointing. Several laboratory-based initiatives aimed at bringing about more responsible use of the laboratory are discussed. Improved education in the judicious use of the laboratory, beginning in medical school and carrying on through the early stages of a physician's career, is considered the most promising long-term approach. This, along with improved communication between the laboratory and the clinic, is the avenue most likely to bring about more responsible use of the clinical laboratory in health care.

Clinical Laboratory Techniques↗
PubMedDate not supplied

Root cause analysis of laboratory delays to an emergency department.

The Q-Probes study has identified benchmark interinstitutional laboratory median turnaround times (TAT) of 25 min for hemoglobin and 36 min for potassium. Our objectives were to measure the emergency department (ED)/laboratory TAT and other relevant laboratory processing and reporting times, and to identify root causes of laboratory delay. A flow chart was developed for the ordering, collecting, analyzing, and reporting of laboratory results. Time intervals were prospectively recorded for complete blood count (CBC) and K+ in a cross-sectional study, using the flow chart, and defined as follows: TAT was the interval from blood draw (BD) to ED report; BD time was the interval from order processing to BD; and order processing time was the interval from physician ordering to the unit coordinator processing the orders. Median times with interquartile ranges are reported. CBC TAT was 38 min (29-51.5), and K+ TAT 58 min (45-76.5). Order processing time was 7 min (4-15). The laboratory assistant BD time was 17 min (8-30) for CBC and 15 min (7.75-32.25) for K+ as compared to 0 min for a nurse, yet the venipuncture method (laboratory assistant technique) had a recollection rate of 1% (1/93) due to hemolysis vs. 20% (19/95) via the i.v. catheter (nurse technique). Of stat ED blood work, 24% was for admitted patients held in the ED. Laboratory reporting times are delayed with these root causes: laboratory assistant availability; recollection rate; volume of tests for ED admitted patients; and order processing time.

Benchmarking↗
PubMed2003

Reliability of quantitative reverse-transcriptase-PCR-based detection of tumour cells in the blood between different laboratories using a standardised protocol.

Differences in methods of reverse-transcriptase (RT)-polymerase chain reaction (PCR)-based detection of tumour cells in the blood gives rise to conflicting results, and standardisation is urgently needed. This pilot study aimed to assess the variation of RT-PCR-based detection of tumour cells in blood between four different laboratories using a commercially available kit with a standardised protocol. This kit allows comparison of results from different laboratories and facilitates the investigation of the influence of pre-analytical parameters. All laboratories analysed identical sets of blood samples spiked with tumour cells in a concentration range of 1-100 tumour cells/ml. To study at which level variation was introduced, three kinds of sample sets were generated in which (i) tumour cell RNA was spiked in the RNA of mononuclear cells (MNC), (ii) tumour cells were spiked in isolated MNC, and (iii) tumour cells were spiked in blood. Real-time quantitative RT-PCR was used to detect and quantify cytokeratin 20 (CK20) expression, which is indicative for the presence of epithelial tumour cells. All laboratories were able to detect CK20 expression in all spiked-RNA samples with limited variation in expression levels between laboratories. There was a positive correlation between the amount of spiked tumour cell RNA and CK20 expression level. RT-PCR analysis of spiked-MNC samples resulted in more variation in the CK20 expression levels between laboratories, however again all spiked samples were reported to be positive by all of the laboratories. The evaluation of spiked-blood samples gave rise to considerable quantitative and qualitative variation between the laboratories. Our results underline the importance and need for standardisation and extended quality control studies in the field of pre-analytics.

HT29 Cells↗
PubMed1999

Video networking of cardiac catheterization laboratories.

BACKGROUND: The purpose of this study was to assess the feasibility and accuracy of a video telecommunication network to transmit coronary images to provide on-line interaction between personnel in a cardiac catheterization laboratory and a remote core laboratory. METHODS: A telecommunication system was installed in the cardiac catheterization laboratory at Kaiser Hospital, Los Angeles, and the core laboratory at the University of California, Irvine, approximately 40 miles away. Cineangiograms, live fluoroscopy, intravascular ultrasound studies and images of the catheterization laboratory were transmitted in real time over a dedicated T1 line at 768 kilobytes/second at 15 frames/second. These cases were performed during a clinical study of angiographic guidance versus intravascular ultrasound (IVUS) guidance of stent deployment. During the cases the core laboratory performed quantitative analysis of the angiograms and ultrasound images. Selected images were then annotated and transmitted back to the catheterization laboratory to facilitate discussion during the procedure. RESULTS: A successful communication hookup was obtained in 39 (98%) of 40 cases. Measurements of angiographic parameters were very close between the original cinefilm and the transmitted images. Quantitative analysis of the ultrasound images showed no significant difference in any of the diameter or cross-sectional area measurements between the original ultrasound tape and the transmitted images. The telecommunication link during the interventional procedures had a significant impact in 23 (58%) of 40 cases affecting the area to be treated, the size of the inflation balloon, recognition of stent underdeployment, or the existence of disease in other areas that was not noted on the original studies. CONCLUSIONS: Current video telecommunication systems provide high-quality images on-line with accurate representation of cineangiograms and intravascular ultrasound images. This system had a significant impact on 58% of the cases in this small clinical trial. Telecommunication networks between hospitals and a central core laboratory may facilitate physician training and improve technical skills and judgement during interventional procedures. This project has implications for how multicenter clinical trials could be operated through telecommunication networks to ensure conformity with the protocol.

Angioplasty, Balloon, Coronary↗
PubMed2003

An inexpensive modification of the laboratory computer display changes emergency physicians' work habits and perceptions.

STUDY OBJECTIVE: Little is known about how the availability of laboratory data affects emergency physicians' practice habits and satisfaction. We modified our clinical information system to display laboratory test status with continuous updates, similar to an airport arrival display. The objective of this study was to determine whether the laboratory test status display altered emergency physicians' work habits and increased satisfaction compared with the time period before implementation of laboratory test status. METHODS: A retrospective analysis was performed of emergency physicians' actual use of the clinical information system before and after implementation of the laboratory test status display. Emergency physicians were retrospectively surveyed regarding the effect of laboratory test status display on their practice habits and clinical information system use. Survey responses were matched with actual use of the clinical information system. Data were analyzed by using dependent t tests and Pearson correlation coefficients. The study was conducted at a university hospital. RESULTS: Clinical information system use by 46 emergency physicians was analyzed. Twenty-five surveys were returned (71.4% of available emergency physicians). All emergency physicians perceived fewer clinical information system log ons per day after laboratory test status display. The actual average decrease was 19%. Emergency physicians who reported the greatest decrease in log ons per day tended to have the greatest actual decrease (r =-0.36). There was no significant correlation between actual and perceived total time logged on (r =0.08). In regard to effect on emergency physicians' practice habits, 95% reported increased efficiency, 80% reported improved satisfaction with data access, and 65% reported improved communication with patients. CONCLUSION: An inexpensive computer modification, laboratory test status display, significantly increased subjective efficiency, changed work habits, and improved satisfaction regarding data access and patient communication among emergency physicians. Knowledge of the test queue changed emergency physician behavior and improved satisfaction.

Clinical Laboratory Information Systems↗
PubMed1993

Vascular laboratory cost analysis and the impact of the Resource-Based Relative Value Scale payment system.

PURPOSE: This study compares the actual cost of performing noninvasive laboratory studies with reimbursement under the previous Medicare Part B system and under current resource-based relative value scale (RBRVS) guidelines. METHODS: We calculated the cost to operate our own laboratory and estimated national costs for small- and large-model laboratories. Reimbursement under Medicare Part B was calculated for each Current Procedural Terminology code from average Medicare reimbursement allowances and national case volumes in 1990, which were obtained from the Health Care Financing Administration. All data were expressed as dollars per hour of study time to allow universal comparison of costs and reimbursement among tests that require differing lengths of time for completion. RESULTS: Technical costs for laboratory time ranged from $143 to $173 per study hour. The largest components of laboratory expenses were fixed costs, including personnel (37% to 46%), equipment (30% to 42%), and facilities (6% to 8%). Variable costs such as billing (9% to 10%) accounted for most of the remainder. More efficient allocation of equipment resulted in lower costs in large laboratories, whereas continued use of depreciated equipment resulted in lower costs in our own laboratory ($127/hr). CONCLUSIONS: We project that technical reimbursement under RBRVS will be $82/hr nationally and $80/hr locally, whereas global reimbursement (technical plus professional) will be $116/hr and $110/hr, respectively. On the basis of 1990 case volumes, the RBRVS system will decrease national global reimbursement by at least 35% compared with the previous Medicare Part B system. Under the new system, technical reimbursement will decrease by an estimated 27% nationally, whereas professional reimbursement will decrease by 52%. Revenue under RBRVS will not meet the cost to perform studies either nationally or locally. Technical reimbursement is 37% to 54% below actual technical costs, and even global reimbursement is 13% to 34% less than technical costs. Our analysis revealed that costs will exceed reimbursement despite maximization of operating efficiency. This analysis applies to outpatients only. A case mix including inpatients will further reduce reimbursement, because only the professional component is allowed. By setting reimbursement of vascular laboratories below actual costs, the new RBRVS system may ultimately reduce the availability of noninvasive vascular testing for elderly patients.

Computer Simulation↗
PubMed1999

Exposures of geotechnical laboratory workers to respirable crystalline silica.

Geotechnical laboratory testing involves the determination of the physical properties of soil, rock, and other building materials for engineering purposes. Individuals working in these laboratories are exposed to airborne soil, rock, and other dusts during the preparation and testing of these materials. Crystalline silica as quartz is a common constituent of these materials and represents a potential hazard to geotechnical laboratory workers when airborne as a respirable dust. The authors conducted an examination of the potential for geotechnical laboratory workers to be exposed to respirable dust and respirable quartz during the performance of three routine laboratory tasks. A task-based exposure assessment strategy was used. Although respirable dust was generated during the performance of each of these tasks, its impact on exposures was generally overridden by the presence of respirable quartz in the dust. Quartz content in the respirable dust ranged from below the detection limit to greater than 50 percent. Mean exposure to respirable quartz, based on the duration of the task and assuming no other exposures for the rest of the 8-hour day, exceeded the National Institute for Occupational Safety and Health (NIOSH) "action level" (the exposure level at which certain actions must be taken) of 0.025 mg/m3. If exposure was assumed to continue for the rest of the 8-hour day at the measured concentration, mean exposure to respirable quartz exceeded the American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV) time-weighted average (TWA), the Occupational Safety and Health Administration (OSHA) PEL, and the NIOSH REL. Seven percent of 57 individual task exposure measurements exceeded the TLV-TWA and the PEL, 18 percent exceeded the REL, and another 12 percent exceeded excursion limits as defined by ACGIH. The results of this study support the conclusion that geotechnical laboratory workers are potentially exposed to respirable crystalline silica as quartz at levels that may be harmful. Because the quartz content of the materials being tested in these laboratories is highly variable and is almost never determined prior to testing, all materials being tested in the geotechnical laboratory should be assumed to contain quartz. Appropriate controls should be used to protect workers from inhaling dusts generated from these materials.

Geological Phenomena↗