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PubMed1998

Effect of population-based interventions on laboratory utilization: a time-series analysis.

CONTEXT: Previous studies have identified methods of decreasing laboratory utilization. However, most were hospital-based, relatively small, single-centered, or of limited duration. OBJECTIVE: To determine the effect of 3 population-based interventions (physician guidelines, laboratory requisition form modification, and changes to funding policy) on laboratory utilization in Ontario. DESIGN: Interventional time-series analysis in which data analysis was based on all claims made to the Ontario Health Insurance Program between July 1, 1991, and April 1997 for laboratory tests affected by the interventions. SETTING: All clinical laboratories (not based in hospitals) in Ontario. INTERVENTIONS: Physician guidelines, modification of laboratory requisition form, and changes in funding policy for the use of the erythrocyte sedimentation rate test (ESR), microscopic urinalysis, tests for renal function, iron stores, serum urea, and serum iron determinations, and tests for thyroid dysfunction (total thyroxine and thyroid-stimulating hormone [TSH]). MAIN OUTCOME MEASURES: Change from 1991 to 1997 in utilization rates of ESR, microscopic urinalysis, serum urea and iron determinations, and tests for total thyroxine and TSH. RESULTS: Age- and sex-standardized rates for laboratory tests unaffected by the interventions were stable during the study period. Utilization of ESR and urea determination decreased by 58% (P<.001) and 57% (P<.001), respectively, after they were removed from the requisition form and guidelines discouraging their use were disseminated. Rates for urinalyses without microscopy increased by 1700% (P<.001), while microscopic urinalysis decreased by 14% (P<.001), after a policy change eliminated microscopic urinalysis from routine urinalysis. Rates of iron determination declined by 80% (P<.001) and ferritin rates increased by 34% (P= .05) when policy changes eliminated iron testing when ordered with ferritin and guidelines advocating ferritin alone for investigating iron deficiency were disseminated. Utilization of total thyroxine testing declined by 96% (P = .02) when the provincial health plan stopped its funding. When TSH was removed from the laboratory requisition form, a 12% decline (P= .03) in its use was observed. Through April 1997, these interventions saved more than 625000 tests or $210400. CONCLUSIONS: The combination of guideline dissemination, laboratory requisition form modification, and changes to funding policy was associated with significant reductions in laboratory utilization.

Clinical Laboratory Techniques↗
PubMed1989

Identification of the major sources of error in estrogen receptor measurements for individual laboratories using both tissue and cytosol samples.

The major sources of error between laboratories performing estrogen receptor measurements in tissue samples were identified for 17 participating laboratories in a trial conducted by the Australasian Quality Assurance programme. Both tissue and cytosol samples were provided, and the In-House assays were compared with the ER-EIA kit (Abbott Laboratories, U.S.A.) as a reference assay. For both the In-House and Abbott assays, tissue samples resulted in a between laboratory CV of about 55% and a within laboratory CV of about 30%. In contrast to tissue samples, the between laboratory CV for cytosol samples was reduced to 41% for the In-House assays and to 33% for the Abbott assay, whereas the within laboratory CV was reduced to 10% for both types of assay. The different methods of tissue homogenization by themselves were not found to be sources of error, and protein extraction efficiency from tissue was strongly correlated with protein measurement (P less than 0.0005). The major sources of error due to protein measurement, cytosol preparation, In-House and Abbott assays were evaluated for individual laboratories. The results indicated absence of any major sources of error for four laboratories, while one, two and three or more sources were indicated for seven, three and three laboratories respectively. The conclusion that about half the participants need to improve their ER assays was confirmed by three independent reviews. Furthermore, the trial demonstrated that tissue samples are essential as quality assurance material for a realistic assessment of ER assays in biopsy specimens.

Animals↗
PubMed1998

New directions in laboratory-clinician communications.

The widespread availability of computer-generated data interpretation of clinical laboratory determinations, as well as computerized patterns of disease progression, has given the laboratory professional a powerful tool to enhance the capability of the laboratory to provide consultation for the clinicians. Additionally, the new advances in technology, and the measurement of disease markers on a molecular basis, has added a whole new dimension to Laboratory Medicine. This explosion of technology is affording the clinical laboratory professional a renewed chance to become a more visible and productive member of the team of health providers. There is a need for clinicians to be educated on the capabilities of these tests and their relative powers of diagnosis. The ability to determine vanishingly small quantities of biological molecules also presents the clinical laboratory with the opportunity to provide knowledge for preventative medicine, and for extremely early detection of onset of a disease or changes in its status. Prediction of genetic predisposition, using sophisticated molecular techniques, is another aspect of the novel expertise which the clinical laboratory professional can use to educate the clinical staff, and allow for earlier counseling and treatment. It is with these tools and knowledge that the clinical laboratory can contribute substantially to overall patient care. This role for the clinical laboratory is all the more urgent since the proliferation of information presents a substantial obstacle to the physician for understanding the molecular basis of a large number of disease processes and how this information can be best used to enhance patient care. The Laboratory Medicine professional of today has the unique opportunity to communicate and exchange knowledge and expertise with clinical counterparts, using a variety of educational and electronic means.

Communication↗
PubMed1999

A survey of infections in United Kingdom laboratories, 1994-1995.

AIMS: To identify the number and type of infections occurring in United Kingdom clinical laboratories during 1994 and 1995, following similar surveys covering 1970 to 1989. METHODS: A retrospective questionnaire survey was undertaken of 397 responding UK clinical laboratories covering 1994 and 1995. A follow up telephone survey was undertaken with each of the laboratories from which a questionnaire had been received indicating a possible or probable laboratory acquired infection during 1994 or 1995. RESULTS: Questionnaires were sent to 659 laboratories or organisations which were thought to have laboratories, of which 557 responded (response rate of 84.5%). Of these, only 397 were from organisations with laboratories. Over 55,000 person-years of occupational exposure were covered, and only nine cases identified, giving an infection incidence rate overall of 16.2/100,000 person-years, compared with 82.7 infections/100,000 person-years found in a similar survey covering 1988 and 1989, reported previously. Infections were commonest in females, in relatively young staff, in microbiology laboratory workers, and in scientific/technical employees. Gastrointestinal infections predominated, particularly shigellosis, but few specific aetiological factors relating to working practices were identified. No hepatitis B cases were reported. CONCLUSIONS: The small number of cases identified indicates high standards of infection control, though there is still room for improvement. Periodic studies of this kind are not adequate for comprehensive monitoring of the incidence of laboratory acquired infections. That will require the introduction of a routine, active surveillance programme or prospective survey which has the support and commitment of the laboratories themselves.

Adult↗
PubMed2006

Laboratory medicine in the 2000s: programmed death or rebirth?

Changes have occurred in the organization, complexity and role of medical laboratories in healthcare, requiring a great increase in global productivity and diagnostic efficiency by enrolled professionals to withstand new challenges. Such a radical evolution, which should be very attractive for new generations of professionals, is counterbalanced by an increasing shortage of laboratory vocations worldwide, particularly in community hospital and large reference laboratories, which may lead to a serious crisis in the field of laboratory medicine in the very near future. Some reasons can be highlighted, including the decreased interaction between clinicians and laboratory professionals, centralized testing, and the development of innovative, minimally invasive techniques that can easily be handled without direct control or supervision by laboratory staff. The prospect of a professional decline in laboratory medicine can be offset by increased awareness of the radical changes occurring within clinical laboratories and re-professionalization of laboratory scientists. This will require new resources to attract young professionals, and should include reaffirmation of the role of laboratory consultants and active participation in the development, implementation and monitoring of innovative diagnostic systems. The "patient" appears to be in a serious condition; it is in our hands to let him be reborn.

Clinical Laboratory Techniques↗
PubMed1999

Establishing a laboratory for surveillance of invasive bacterial infections in a tertiary care government hospital in a rural province in the Philippines.

A clinical bacteriologic laboratory was established in a tertiary care government hospital in The Philippines, where expert bacteriologic laboratories do not usually exist at this level of health care. The laboratory was jointly established by the Research Institute for Tropical Medicine (RITM) (Manila, The Philippines) and the National Public Health Institute (KTL) (Helsinki, Finland). The laboratory was planned, its personnel were trained, and its functioning was continuously supported by the RITM and KTL. The following aspects were of utmost importance in establishing the laboratory and launching its work: 1) the support of the RITM bacteriologic laboratory, with back-up and consultations from KTL; 2) creation and maintenance of personal contacts between clinicians and laboratory staff with an emphasis on clinical relevance and rapid reporting of laboratory results; 3) the consideration of the quality aspects of the work from the start; and 4) keen follow-up of the bacteriologic results and their clinical significance and use, of practical laboratory work, and of quality assurance aspects. In the first two years of its operation, the laboratory identified Streptococcus pneumoniae and Haemophilus influenzae as the most important causes of severe pneumonia, sepsis or meningitis in children less than two years of age, and Salmonella typhi as the most frequent significant isolate from the blood cultures, being found most often in school age children and young adults.

Adolescent↗
PubMedDate not supplied

The laboratory information float, time-based competition, and point-of-care testing.

A new term, the laboratory information float, should be substituted for turnaround-time when evaluating the performance of the clinical laboratory because it includes the time necessary to make test results both available (ready to use) and accessible (easy to use) to clinicians ordering tests. The laboratory information float can be greatly reduced simply by telescoping the analytic phase of laboratory testing into the preanalytic phase. Significant costs are incurred by such a change, some of which can be reduced by developing a mobile clinical laboratory (sometimes referred to as a "lab-on-a-slab" or "rolling thunder") to transport the analytic devices directly to patient care units. The mobile clinical laboratory should be equipped with an integrated personal computer that can communicate continuously with the host laboratory information system and achieve some semblance of continuous flow processing despite test performance in point-of-care venues. Equipping clinicians with palmtop computers will allow the mobile clinician to access test results and order tests on the run. Such devices can be easily configured to operate in a passive mode, accessing relevant information automatically instead of forcing clinicians to query the laboratory information system periodically for the test results necessary to render care to their patients. The laboratory information float of the year 2,000 will surely be measured in minutes through the judicious deployment of relevant technology such as mobile clinical laboratories and palmtop computers.

Clinical Laboratory Information Systems↗
PubMedDate not supplied

Future directions for research in laboratory medicine: the findings of a Delphi survey of stakeholders.

In July 1995, we asked 101 experts to anticipate future areas for research in clinical laboratory medicine using a modified Delphi survey approach. The panel included academicians, clinical laboratory professionals, laboratory managers, practicing physicians public health officials, hospital administrators, and representatives of manufacturing industries, managed care organizations, commercial laboratories, and government health agencies. The participants predicted fewer laboratories, more automation, and fewer skilled staff needed in the future. The consensus was that laboratory quality assurance will focus on patient outcomes and be benchmarked against peer groups. They agreed that quality assurance routinely will be integrated into testing kits. Measures derived from medical informatics, such as outcomes analysis and utilization statistics, will become a standard feature of health care. A major area of concern was the effect that reorganizing health care and striving for cost containment will have on laboratory services. These views were consistent with those expressed by participants at a CDC conference on the frontiers of laboratory medicine research held shortly after the study was completed. These topics by now are familiar to most laboratory professionals, and we urge them to explore the many research issues raised with their colleagues in their clinical laboratories, health-care organizations, and industry.

Attitude to Health↗
PubMed1999

[International trends in clinical laboratory testing].

During the 20th century, at least until the 1980s, clinical laboratory practice had been rapidly expanded, mainly because of a significant advancement in medicine as a whole and also in laboratory technology. However, recent economic changes in health care environment worldwide have been influencing greatly future trends in clinical laboratory practice. In 1983, the DRG/PPS was introduced in the Medicare hospital care in the United States, and it will be introduced also in out-patient care after the January of 2000. This payment system has been expanded to the HMO, and a drastic change has occurred in clinical laboratory practice, particularly since 1988 when the CLIA'88 was implemented. In Japan, the DRG/PPS is now in the process of preparing for the future introduction into the National Health Insurance System. The clinical laboratory must pursue both quality management and adequate utilization of laboratory tests. In near future, the ISO standards in clinical laboratory testing will prompt to the implementation of quality management in the clinical laboratory. Evidence-based laboratory medicine or systematic review in diagnostic testing will be introduced in order to improve the utilization of clinical laboratory tests.

Clinical Laboratory Techniques↗
PubMed2005

[Role of clinical laboratory in Japanese general hospital for equilibrium functional tests].

Recent automation in clinical laboratories affords healthcare providers with numerous options in terms of physiological tests. However, the role of the clinical laboratory in the field of equilibrium functional tests is not clearly defined. Therefore, we conducted a questionnaire survey to define the role of clinical laboratories in general hospitals. We present the results of our investigation and the approach employed by the clinical laboratory of our hospital. Rates of healthcare providers desiring the conduct of equilibrium functional tests by clinical laboratories were 78% and 70% in otolaryngology and neurosurgery departments, respectively; moreover, 92% of technologists from clinical laboratories responded that an equilibrium functional test can be performed upon request. Furthermore, 84% of clinical laboratory staff members and 77% of staff from neurosurgery departments agreed that implementation of a system allowing each department to request equilibrium functional tests from the clinical laboratories is necessary. This finding was indicative of the high demand for equilibrium functional tests by clinical laboratories. Therefore, equilibrium functional tests offered by clinical laboratories not only reduce the workload of the otolaryngology department, but also result in a major contribution with respect to management of the entire hospital in terms of high quality examination findings and allocation of healthcare providers in other departments.

Clinical Laboratory Techniques↗
PubMed1996

Atypical squamous cells of undetermined significance. Current laboratory practices of participants in the College of American Pathologists Interlaboratory. Comparison Program in Cervicovaginal Cytology.

OBJECTIVE: To evaluate current laboratory practices and rates for atypical squamous cells of undetermined significance (ASCUS), a category of epithelial cell abnormality in the Bethesda System. DESIGN: Questionnaire surveys were mailed in December 1993 and March 1994. SETTING: Cytopathology laboratory participants in the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology (PAP). RESULTS: Most responding laboratories (82.5%) limited the use of "atypia" terminology to abnormalities of undetermined significance. Nearly half of the laboratories employed only the term ASCUS for squamous epithelial changes in this category. The median rate of ASCUS in 1993 was 2.8%, with 10% of laboratories reporting rates greater than 9.0%. The median squamous intraepithelial lesion rate was 2.0%, with a median ASCUS-squamous intraepithelial lesion ratio of 1.3. The majority of laboratories qualified a portion of ASCUS cases and issued recommendations for follow-up when appropriate. Fifty-six percent of laboratories surveyed included patients diagnosed with ASCUS in follow-up programs. Laboratories estimated that about 20% (median response) of patients with ASCUS smears had a squamous intraepithelial lesion or equivalent diagnosis made within a year's follow-up. CONCLUSIONS: The ASCUS category is used by the majority of laboratories as recommended by the Bethesda System, but reporting rates vary. The results of this survey and associated surveys provide laboratories with useful benchmark figures for interlaboratory comparison of ASCUS practices.

Cervix Uteri↗
PubMed1997

Computer-based neuroanatomy laboratory for medical students.

BACKGROUND: To present the laboratory portion of our first-semester Human Neuroanatomy course at Temple University Medical School more effectively and efficiently and to replace the glass slide/microscope-based laboratory component of the course, we developed a computer-based substitute. METHODS: For this computer-based neuroanatomy laboratory program, we photographed the (a) gross brain sliced and dissected specimens and (b) all the glass slides, from the sacral cord through the head of the caudate nucleus. We digitized the photographed images and, using Multimedia ToolBook (Asymetrix), created a computerized atlas, laboratory guide, and a clinical problem-solving section. To assess the effectiveness of the computerized laboratory, we compared student performances between those classes that previously had the traditional laboratory with two succeeding classes that used the computer-based laboratory. RESULTS: Test score results of the laboratory portion of the course suggested that performance on laboratory material was virtually unchanged by the substitution of the computer program. By a survey taken at the end of the course, the students were very satisfied with the computerized program as a teaching method. CONCLUSIONS: The students and faculty enthusiastically agreed that the computer program was an effective substitute method for the traditional glass-slide laboratory and that it was a beneficial self-educational tool that fostered independent learning. The program encouraged student interaction and group learning and fostered independence. It was a more efficient method for faculty and students without sacrificing performance.

Computer-Assisted Instruction↗
PubMed2003

Appropriateness in programs for continuous quality improvement in clinical laboratories.

BACKGROUND: External reviews and the accreditation of medical laboratories involve more than the mere assessment of conformance with standards for organisational processes. The new approaches to quality improvement suggest that, rather than using inspection to correct unusual errors, there should be more emphasis on improving the processes of health care to ensure that desired outcomes are produced. Appropriateness plays a key role in programs for quality improvement. METHODS: Appropriateness in laboratory medicine can be assessed, and improved, through the governance of the entire testing process. This begins with test selection, proceeds through valuable pre-, intra- and post-analytical procedures, and concludes by assuring the correct interpretation and utilization of laboratory information. RESULTS: The International Standard, specifically developed for medical laboratories (ISO 15189) recognizes the value of appropriate interpretation and advisory services, although it does not specify requirements for assessing appropriateness, requesting tests and interpreting results. The effectiveness of clinical laboratories can be assessed by using surrogate markers, which indicate physicians' satisfaction, and clinical audits. Effectiveness is also enhanced by stressing the importance of the technical and professional competence of evaluators. CONCLUSIONS: Inappropriate laboratory utilization unjustifiably increases health care costs, can harm patients and perpetuates the vision of laboratory testing as a commodity. Improvement in laboratory appropriateness can be achieved by seeking a better relationship with physicians and by stressing the role of laboratory specialists in providing clinical advice for the selection of laboratory tests, and the interpretation and utilization of their results, thus leading to more satisfactory clinical outcomes.

Clinical Laboratory Techniques↗
PubMed2003

Error budget calculations in laboratory medicine: linking the concepts of biological variation and allowable medical errors.

BACKGROUND: Random, systematic and sporadic errors, which unfortunately are not uncommon in laboratory medicine, can have a considerable impact on the well being of patients. Although somewhat difficult to attain, our main goal should be to prevent all possible errors. A good insight on error-prone steps in the laboratory process is essential to achieving a structured system for error reduction. METHODS: Here, the process of laboratory medicine is divided into phases, and for each phase, an error frequency is presented. While error frequencies in the laboratory (pre-analytical to post-analytical) have been reported elsewhere, we also include them in the present paper. In order to investigate error frequencies in the pre-pre- and post-post-analytical phases, clinicians were asked to carefully answer questions concerning their ordering strategies for laboratory investigation and their interpretation of results. RESULTS: In the present study, the overall error rate in laboratory medicine was found to be 20.0%. The error percentages in the pre-pre- and post-post-analytical phase were about 12.0% and 5.0%, respectively. This indicates that, also on the clinical side, error reduction is desirable, especially in the requesting of laboratory investigation. Error reduction can be achieved through process redesigning by, for example, applying the Hazard Analysis and Critical Control Points approach. The error budget that clinicians might spend, based upon critical differences, is 26.9%. For the same test set and production circumstances, the overall biological variation is 7.9%. Clinicians thus take the error rates into account in their practical, daily use, and the ultimate achievable in laboratory medicine is biological variation. CONCLUSIONS: Several currently available software applications can aid error reduction in clinical chemistry. Both laboratory consultants and the use of information and communication technology are essential tools in optimizing the efficiency of laboratory medicine.

Budgets↗
PubMed1999

Inter-laboratory validation of an ELISA for the determination of serum anti-ganglioside antibodies.

Anti-ganglioside antibodies are frequently sought in the sera of patients with autoimmune peripheral neuropathy, using an enzyme-linked immunosorbent assay (ELISA) as the principal method for antibody detection. Wide variations in assay performance between laboratories have been reported. In this study, we established a standardized ELISA method between laboratories within the European Inflammatory Neuropathy Cause and Treatment (INCAT) group and determined the inter-laboratory variance in assay performance using both the standardized INCAT method and in-house local methods. As expected, the inter-laboratory variances were greater using local methods than using the standardized method, producing titre estimates which could be 24.8 or 7.6 times larger or smaller, respectively, than the true means for these laboratories. Using the standardized method, the within laboratory measurement error accounted for 41% of the inter-laboratory variation, providing a theoretical upper limit to which technical improvements within laboratories could reduce inter-laboratory variation. These data describe the intrinsic weaknesses within the widely used ganglioside antibody ELISA methods and reinforce the importance of inter-laboratory cooperation within this area. Standardized serological reagents used in this study are available from INCAT members.

Antibodies↗
PubMed2005

Comparison and interpretation of urinalysis performed by a nephrologist versus a hospital-based clinical laboratory.

BACKGROUND: Urinalysis (UA) is considered the most important laboratory test in evaluating patients with kidney disease. Anecdotally, we have observed differences between results of UA performed by nephrologists compared with those performed by certified medical technologists or clinical laboratory scientists that could affect a clinician's diagnosis. Whether there are differences between UA performed by the clinical laboratory and that performed by a nephrologist was determined, and accuracy of diagnosis based on interpretation of the UA was compared. METHODS: Urine samples were obtained from 26 patients with acute renal failure (ARF). An aliquot of urine was sent to the clinical laboratory for UA. Nephrologist A, blinded to the patient's clinical information, performed a UA on the other aliquot of urine, generated a report, and assigned the most likely diagnosis for ARF based on UA findings. Nephrologist B, also blinded to the clinical information, reviewed nephrologist A's UA reports and assigned a diagnosis for ARF to each report. Nephrologists A and B both assigned a diagnosis (or diagnoses) for the ARF based on laboratory UA results. These 4 sets of diagnoses were compared with those assigned by the consult nephrologists. RESULTS: Nephrologist A correctly diagnosed the cause of ARF in 24 of 26 samples (92.3% success rate) based on his performance of the UA. Diagnoses by nephrologists A and B, based on their review of the clinical laboratory UA report, were correct in only 23.1% and 19.2% of the samples, respectively. Accuracy of diagnosis for nephrologist B improved to 69.3% when she reviewed UA reports from nephrologist A. Nephrologist A's review of urine sediment was significantly more accurate than interpretations by nephrologist A or B of clinical laboratory reports (sign test, P < 0.001). Nephrologist A reported a greater number of renal tubular epithelial (RTE) cells (P < 0.0001), granular casts (P = 0.0017), hyaline casts (P = 0.0233), RTE casts (P = 0.0008), and dysmorphic red blood cells. The laboratory noted a greater number of squamous cells (P = 0.0034). CONCLUSION: A nephrologist is more likely to recognize the presence of RTE cells, granular casts, RTE casts, and dysmorphic red blood cells in urine. The laboratory may be reporting RTE cells incorrectly as squamous epithelial cells. Nephrologist-performed UA is superior to laboratory-performed UA in determining the correct diagnosis.

Academic Medical Centers↗
PubMed1985

Education, training, professional certification, and work patterns of directors in interstate laboratories.

Education, professional training, certification, and work patterns of 988 laboratory directors employed in 440 clinical laboratories licensed under the Clinical Laboratories Improvement Act of 1967 are examined. Directors of hospital laboratories as opposed to independent laboratories were more likely to be physicians (82.8% vs. 68.0%), to have completed a formal residency program (75.5% vs. 62.0%), and to be certified in both anatomic and clinical pathology (65.3% vs. 57.1%). Only 51.9% of pathologists confined their work to a single laboratory, while 64.8% of directors with Ph.D.s or other doctorates directed only one laboratory. Most laboratories (81.5%) have at least one associate director. Hospital directors are more often full time (30 or more hours per week) than their independent laboratory counterparts, 74.4% vs. 42.4%, respectively. When the education and experience of individuals entering the field between the 1950s and 1970s are examined, it is evident that fewer individuals with bachelor's or master's degrees now are able to qualify as laboratory directors.

Certification↗
PubMed2003

The performance of laboratories analysing alpha-quartz in the Workplace Analysis Scheme for Proficiency (WASP).

The Workplace Analysis Scheme for Proficiency (WASP) is a proficiency testing (PT) scheme for the analysis of occupational hygiene and environmental air samples and is operated in the United Kingdom by the Health and Safety Laboratory (HSL) on behalf of the Health & Safety Executive (HSE). One of the 26 analytes available to laboratories is silica (alpha-quartz) on 25 mm Gelman GLA5000 filters. This paper investigates the performance of laboratories participating in the scheme since the HSL took over the production of the samples in 1998. The average relative standard deviation (RSD) of results obtained by a laboratory is 11.5%. This is reduced to 8.5% when the values from laboratories using indirect analytical methods are excluded. Laboratories using indirect analytical methods accounted for some of the most variable data. For the on-filter analytical methods the data suggested a relationship between relative standard deviation and loading that increased gradually from +/-4% at high analyte levels to +/-10-15% at low levels. The average precision estimate for the on-filter analytical methods was found to be 5.6% RSD for the infrared technique and 6.7% RSD for the X-ray diffraction technique. These figures compare favourably with those reported in the published HSE methods. No significant difference was found between the average result reported by laboratories using on-filter infrared (IR) analysis and the average result reported by laboratories using on-filter X-ray diffraction (XRD) analysis. An ANOVA analysis found the repeatability estimate was just as large as the 'between laboratory' variation for both the XRD and IR on-filter analysis techniques. When a limited number of 'realistic' samples were included in the scheme, XRD analysis was found to perform slightly better than IR analysis. The performance of laboratories in the WASP scheme compares very favourably with other published data from a PT scheme where indirect silica analytical methods are predominately used.

Air Pollutants, Occupational↗