National Proficiency Research Articles

Determination of some inorganic anions in soil extracts and atmospheric deposition using capillary electrophoresis

Four different running capillary zone electrophoresis (CZE) buffers suitable for an indirect photometric detection were studied. The influence of several variables (buffer pH, concentration of electrophoretic flow modifiers, capillary diameter and applied voltage) on determination of chloride, sulphate, nitrate, fluoride, and phosphate was tested for each buffer. All the tested buffers proved to be suitable for the determination. PMA‐TEMED running buffer (pyromellitic acid‐tetramethylethylendiamine) was finally adopted for further investigation. The optimized PMA‐TEMED method was tested on several hundred samples of atmospheric deposition taken in the Czech Soil Monitoring Programme and lyzimetric waters from experimental stations. For analysis of water soil extracts six different soils from international and national soil proficiency tests were analyzed. Analysis of the water soil extracts was more complicated than analysis of atmospheric deposition because more unknown peaks were detected. Concentration of phosphorus in the water soil extracts was usually lower than the detection limit of the method. The proposed method proved to be suitable for determination of chloride, sulphate, nitrate, and fluoride in atmospheric deposition, lyzimetric waters, and soil water extracts.

National versus international asbestos fibre counting schemes: Comparison between the Spanish interlaboratory quality control programme (PICC-FA) and the asbestos fibre regular informal counting arrangement (AFRICA)

An interchange of eight asbestos reference slides was planned informally between the Spanish national proficiency testing scheme, PICC-FA, and its international counterpart, AFRICA. The fibre counting levels, the reference values and the differences in performance assessments for individual counts and laboratories were analysed to test the level of agreement between the schemes. Comparisons were based on the proportions of fibre counts within and outside limit values. Discrepancies were found between schemes in the classification of counts, with the position of the limits of satisfactory performance being the most important factor of disagreement. The AFRICA limits are over twice as wide as the PICC-FA limits, though only 17% of the counts are affected by this large difference. There were not found to be significant differences in the assessment of the performances of Spanish laboratories—87.5% would have achieved a satisfactory classification in both schemes. A possible new approach to harmonizing proficiency testing schemes is discussed.

National versus International Asbestos Fibre Counting Schemes: Comparison between the Spanish Interlaboratory Quality Control Programme (PICC-FA) and the Asbestos Fibre Regular Informal Counting Arrangement (AFRICA)

An interchange of eight asbestos reference slides was planned informally between the Spanish national proficiency testing scheme, PICC-FA, and its international counterpart, AFRICA. The fibre counting levels, the reference values and the differences in performance assessments for individual counts and laboratories were analysed to test the level of agreement between the schemes. Comparisons were based on the proportions of fibre counts within and outside limit values. Discrepancies were found between schemes in the classification of counts, with the position of the limits of satisfactory performance being the most important factor of disagreement. The AFRICA limits are over twice as wide as the PICC-FA limits, though only 17% of the counts are affected by this large difference. There were not found to be significant differences in the assessment of the performances of Spanish laboratories—87.5% would have achieved a satisfactory classification in both schemes. A possible new approach to harmonizing proficiency testing schemes is discussed. © 1998 British Occupational Hygiene Society. Published by Elsevier Science Ltd.

Pathology and genetic testing

By reporting on the possible existence of a hereditary cancer and recommending further genetic evaluation, the pathologist can help identify families with hereditary cancer. Currently, however, recognition of a case of hereditary cancer relies predominantly on clinical criteria, as common cancers show only a few specific pathologic features that suggest hereditary predisposition. Furthermore, clinical criteria alone often fail to identify mutant gene carriers. In contrast to genes that have a high penetrance for causing cancer, such as BRCA1, APC, RET, and the mismatch repair genes, identifying carriers of mutant genes having a lower penetrance (as is the case for the BRCA2 gene) is more difficult. Studies to identify markers for mutant germline cancer-predisposing genes will typically require studying archival tissue specimens, but germline genetic testing on archival samples for research purposes is complicated by the need for patient consent unless specimens are stripped of their patient identifiers. Pathologists contemplating such research should seek informed consent for genetic testing prior to archiving tissues. The need for consent has led to concerns that certain types of cancer research projects will no longer be feasible; if patient consent has not been obtained, however, institutional review board-approved protocols that facilitate obtaining patient clinical data while maintaining patient confidentiality can overcome this problem. As clinical genetic testing for hereditary cancer becomes part of clinical practice, there are many concerns about the quality of service at each step in the process. One of the most important requirements for quality is to ensure that the performance of a genetic test is always linked to adequate pretest and posttest genetic counseling. Reporting of genetic test results should be standardized and include information about the technique used to identify mutations, the sensitivity and specificity of the test in detecting such mutations, and the limitations of the test. The report should also contain recommendations for further action and information packets to assist in the interpretation of the test. Pathologists have expertise in the area of laboratory proficiency testing and can play an important role in the establishment of a national proficiency program to ensure a quality genetic testing process. Cancer 1997; 80:636-48. © 1997 American Cancer Society.

Quality assurance issues in DNA image cytometry

DNA image cytometry is currently used in many clinical laboratories as a prognostic tool for the study of patients with malignant neoplasms. However, quality assurance (QA) procedures for image cytometry (IC) have not been standardized. National proficiency testing programs for DNA IC are yet to be developed. We describe our QA program for DNA IC. Indicators of quality; thresholds for evaluation; methods for collection, organization, and evaluation of data; and actions recommended to deal with problems are described for each of the phases of DNA IC. They include QA procedures for sample acceptability; staining technique; instrumentation, including linearity and calibration verification; and correlation with other cytometric methods. The difficult problem of standardizing the postanalytical phase of QA is discussed. The need for a consensus conference to adopt standardized QA procedures for DNA image analysis is emphasized. © 1996 Wiley-Liss, Inc.

Quality assurance issues in DNA image cytometry.

DNA image cytometry is currently used in many clinical laboratories as a prognostic tool for the study of patients with malignant neoplasms. However, quality assurance (QA) procedures for image cytometry (IC) have not been standardized. National proficiency testing programs for DNA IC are yet to be developed. We describe our QA program for DNA IC. Indicators of quality; thresholds for evaluation; methods for collection, organization, and evaluation of data; and actions recommended to deal with problems are described for each of the phases of DNA IC. They include QA procedures for sample acceptability; staining technique; instrumentation, including linearity and calibration verification; and correlation with other cytometric methods. The difficult problem of standardizing the postanalytical phase of QA is discussed. The need for a consensus conference to adopt standardized QA procedures for DNA image analysis is emphasized.

The Yorkshire slide exchange external quality assessment (EQA) scheme.

A slide circulation scheme measuring cervical screening performance of individual cytologists in 15 laboratories in Yorkshire Regional Health Authority is described. The advantages and disadvantages are compared with the current National Proficiency Testing (NPT) scheme. The results indicate that a slide circulation scheme can be successfully used in cervical cytology external quality assessment (EQA). Levels of participation are better than those currently achieved by regional variations of the NPT scheme, and the use of laboratory consensus in the selection of scoring slides appears to be no less valid than the use of a pre-selected slide pool assembled by an expert panel. The volume of data accumulated in one round is considerably greater than that achieved by proficiency testing and the educational value is regarded as high. However, the scheme is very time consuming for participants and consequently expensive for laboratories. The lack of external supervision increases the risk of unfair practices within individual laboratories. Because of these problems, Yorkshire has now switched to an NPT scheme.

United States Environmental Protection Agency National Radon Proficiency Programmes

Abstract The US Environmental Protection Agency's voluntary National Radon Proficiency Programmes: Radon Measurement, and Reduction Proficiency are described, including their history and development, current status and future directions. The Radon Measurement Proficiency (RMP) and Radon Contractor Proficiency (RCP) programmes are fundamental to the Agency's programme to reduce the health risk associated with exposure to elevated radon levels in indoor air. Originally developed to provide technical assistance to States, the proficiency programmes now offer US consumers assurance of the quality of their radon measurements and reduction jobs. In other words, the proficiency programmes provide a means to consumers for deciding from which organisations or individuals to purchase radon services. This is especially important in the United States where most radon services are acquired through private enterprises rather than through the public sector. The Agency encourages the public to purchase radon measurement and reduction services only from organisations or individuals that have met the requirements of EPA's proficiency programmes. An increasing number of States require an EPA proficiency listing for their radon registration, licensing, and certification programmes. EPA estimates that about 85% of US companies offering radon services are participating in its proficiency programmes. Consequently, the Agency believes that the development and growth of quality radon services has kept pace with consumer demand. The United States markeplace for residential radon measurement and mitigation services has been dynamic since its inception in the mid-1980s. The fluidity of the market is likely to continue, with some significant changes appearing imminent. The US Congress is now considering legislation that would require participation in the Agency's radon proficiency programmes. In addition, this legislation contains provisions that would encourage consumer testing. Increased testing, coupled with a mandatory national proficiency programme, is likely to result in an increase in the quality of radon services available to the US public.

Proficiency Testing of Factor VIII:C Activitiy Assays at the Canadian Red Cross Society National Reference Laboratory

A national proficiency testing program has been established to monitor the accuracy and precision of factor VIII:C (FVIII:C) assays performed at the various Blood Services Centres of the Canadian Red Cross Society involved in the collection and processing of either donor blood designated for component production or plasma destined for fractionation. This paper describes the preparation, design, and results of the first four exercises involving 19 laboratories. The exercices were designed to allow the investigation of intralaboratory variability between replicate samples and precision of assays as well as the causes of interlaboratory variability. The implementation of this program has led to improved precision and interlaboratory agreement on FVIII;C assays. These improvements were achieved mainly as a result of a modification in the method for sample dilution, an increase in both replicate testing of the same sample and the number of sample dilutions, and a reduction in the number of reagent systems used by various centres.

Performance of Proficiency Survey Samples in Two Immunoradiometric Assays of Human Growth Hormone and Comparison with Patients' Samples

The immunoradiometric assay (IRMA) used in our laboratory for the measurement of growth hormone (hGH; somatotropin) performed badly in the national proficiency survey program, the U.K. External Quality Assessment Scheme (EQAS). We compared our assay with another IRMA, which gave similar results for patients' samples and performed adequately in EQAS. The samples from EQAS are collected from patients with polycythemia and fall into two categories: those containing endogenous hGH and those supplemented with pituitary-derived hGH. Analysis of the two groups separately showed that the differences between the two IRMAS were in the measurement of the endogenous hormone. The reason for this appears to be a matrix effect related to the fact that the EQAS serum samples are collected from polycythemic patients.

Factors Associated With The SOEP And Career Objectives Of The 1984 Regional And National Proficiency Award Winners

Factors Associated With The SOEP And Career Objectives Of The 1984 Regional And National Proficiency Award Winners

Medically useful criteria for analytic performance of laboratory tests.

To establish medically useful guidelines for analytic precision of commonly used clinical laboratory procedures, the authors conducted a mail survey of physicians selected randomly from national lists of specialists. They were asked to review, briefly, outlined clinical problems and select the change in test results that would alter their diagnosis or treatment or prompt further assessment of the patient's condition. The responses were used to calculate goals for laboratory precision that are sufficient to meet the present requirements of the average physician. The medically useful limits were compared with existing performance of laboratories as reported in national proficiency surveys and regional quality control programs. Almost all the common laboratory procedures they studied are being assayed at a precision level adequate for the perceived needs. The authors suggest that, for the more common constituents, further progress in clinical laboratory testing will depend on factors other than the improvement of analytic precision.

Proficiency Testing in Forensic Toxicology: A Feasibility Study

This study has shown that a national proficiency testing program in forensic toxicology is feasible. Samples that resemble typical case specimens were prepared and shipped to approximately 100 laboratories. Participation varied between 61 and 73%. Tissue samples obtained from laboratory animals can be used to simulate those encountered by forensic toxicologists. This has been demonstrated using liver homogenates from animals administered pentobarbital and methaqualone and propoxyphene and acetaminophen. There was a large coefficient of variation however, for the quantitation of acetaminophen in liver. The qualitative data obtained during the course of this study showed a very low incidence of false positives. However, there was a disappointingly low percentage of positive responses for (a) low concentrations of secobarbital and (b) the opiate narcotics (morphine and codeine) in blood, despite the fact that sensitive immunoassay procedures are available for detecting these particular compounds in blood samples. The quantitative determination of drugs and metabolites, other than ethanol, shows wide interlaboratory variation. This variation is presumably not a result of the use of different analytical techniques, since gas liquid chromatography was used by the majority of participants to quantitate drugs and metabolites. Forensic toxicologists are willing to participate in a voluntary proficiency testing program conducted by an independent agency. The performance data developed in this study can serve as a baseline for current forensic toxicology laboratory functional capability in the assessment of future changes and improvements in analytical forensic toxicology.

Proficiency testing for agriculture, horticulture and forestry in England and Wales

This paper deals with the arrangements currently existing for the provision of a proficiency testing service for agriculture, horticulture and forestry in England and Wales. It outlines the background history to the development of the service, records the philosophy behind the structure and development of national proficiency tests, deals with the administration of the service at national and local level, the recruitment and training of industrially based examiners and the maintenance of the standards that they apply and discusses the opportunities that the scheme may offer to developing countries.

Quality control limits for ampicillin, carbenicillin, mezlocillin, and piperacillin disk diffusion susceptibility tests: a collaborative study.

A multilaboratory in vitro study was carried out to determine disk diffusion susceptibility testing quality control limits for two new semisynthetic penicillins, mezlocillin and piperacillin. Existing limits for carbenicillin and ampicillin were reevaluated. Multiple tests (which followed standards set by the National Committee for Clinical Laboratory Standards ASM-2 revised) were performed in nine laboratories by different technologists using disks and Mueller-Hinton agar from different manufacturers. Clinically significant differences between disks produced by different manufacturers were not noted. Inhibitory zone diameter measurements from all laboratories were analyzed, and upper and lower control limits were established by using the overall median +/-0.5 the median range of the individual laboratory measurements as determining parameters. Close agreement of the data in this study with the results of national proficiency testing and quality control programs for ampicillin and carbenicillin supports the validity of our approach to making initial recommendations for quality control guidelines for new antimicrobial agents.

Proficiency testing in agriculture.

The development and organisation of proficiency testing in agriculture in England and Wales is described. The National Proficiency Tests Council, which was established as an independent examining body in 1971, is responsible for administering the proficiency testing scheme at a national level. On passing a category based proficiency test an agricultural worker may apply for a craftsman's certificate and is then entitled to a wages premium under the Agricultural Wages Board's Wages Structure Scheme. The development and format of a series of new category based tests for livestock production, which were introduced in January 1976, is outlined.

National and Local Proficiency Tests: Their Validity for an Introductory Biology Course

The study involved comparison of three proposed proficiency tests for a two-quarter introductory biology course. One of the tests was a nationally standardized examination; the other two were locally constructed. The three tests were administered as first course pretests and as posttests each quarter of the sequence. Course grades were determined independently of the proficiency test scores. The College Entrance Examination Board's College Placement Test for Biology (CEEB Biology) yielded the highest validity between pretest scores and first and second quarter grades. Posttest scores earned during both the first and second quarter on the locally constructed Berg-Miller Proficiency Examination (BMPE) were more highly correlated with final grade in both the first and second quarter than were posttest scores on either the CEEB Biology or the locally constructed Garoian Proficiency Examination (GPE).