Proficiency testing, Clinical Laboratory

The direct and immediate use of laboratory data in medical diagnostic decision making is unique, so the proper use of reference materials in conjunction proficiency testing clinical chemistry is vital if false and mis diagnosis is to be avoided. 

An active program of surveillance of the quality of the immunostains produced must be defined. The primary elements of such a quality assurance (QA) program include procedures and policies for patient test management, quality control, proficiency testing, comparison of test results, relationship of clinical information to patient test results, personnel assessment, communications, complaint investigations, QA review with staff, and QA records. The documentation and review by the laboratory director of all QA procedures is imperative and cannot be overstressed. A brief explanation of each of the QA elements is as follows ... 

Some important assays commonly used in biochemical genetics laboratories do not provide quantitative data (e.g. MPS-EP, qualitative urinary organic acid analysis, AA-TLC). In addition, all successful investigations depend heavily upon selection of the correct analytes to measure and the appropriate interpretation of the quantitative or qualitative results in their clinical context. These challenges suggest a requirement for external quality assessment or proficiency testing schemes that can inform participants about their performance in these areas when compared with other centres. 

Improving the quality of the biomonitoring laboratories that analyze human samples for the purposes of diagnosis, prevention, treatment, or health assessment. These laboratories are regulated under the Clinical Laboratory Improvement Amendments (CLIA) of 1988 (42 CFR 493 [2000]). However, the focus of this statute is mainstream clinical testing. For example, the 41-page CLIA tabulation of approved proficiency-test providers lists only one environmental chemical (blood lead) (CMS 2005). 

Most situations where proficiency evaluation is applied are rather narrowly defined as to scope. For example, clinical laboratories may be asked to demonstrate that they can determine certain constituents occurring in human serum with uncertainties not to exceed specific limits. Accrediting bodies will require successful participation in periodic proficiency tests conducted by a reference laboratory which they recognize. 

In Germany, the Federal Medical Association prescribes the use of IFCC enzyme reference procedures in clinical laboratory practice. Accordingly, the evaluation of participants results in the proficiency testing system is based on IFCC reference procedure values. 

National Committee for Clinical Laboratory Standards. Continuous quality improvement Essential management approaches and their use in proficiency testing Proposed Guideline GP22-P. Wayne PA National Committee for Clinical Laboratory Standards, 1997,... 

Immunoturbidimetry and immunonephelometry are widely used to measure apo A-I and apo B-lOO, which are present at relatively high concentrations. According to the College of American Pathologists Proficiency Testing Survey, all clinical laboratories in the United States that are involved in the measurement of apo A-I and apo B-lOO use one of these two approaches. Alternatively, more sensitive techniques, such as ELISA and RIA, are perhaps more suitable for those apolipoproteins present at much lower concentrations, such as apo C-I and apo C-IL Additional information about the various analytical techniques used in the determination of apolipoprotein concentrations is provided later. 

Assay methods used for TDM should be accurate and reproducible. All clinical laboratories with a TDM service should be actively involved in an internal quality control and external proficiency testing program. In addition, sample volume and assay turnaround time should be considered in selecting the most appropriate analytical method,... 

External quality assurance (EQA) is fundamental to the standardization of clinical laboratory methods because it provides a means to compare results generated in one laboratory with those of peer laboratories subscribing to the same EQA program. EQA programs are especially beneficial since internal QA and QC procedures are limited in their ability to detect bias in analytical methods. Internal QA/QC can only detect errors that result in a deviation from the original method validation inherent errors in the method may go unnoticed. Therefore, it is helpful to compare the results produced by a new method with those from other laboratories (Burtis and Ashwood, 2001). Monitoring the performance of laboratory procedures in a consistent manner keeps the laboratory accountable, and can reveal systematic errors that would otherwise be undetected. A prominent component of EQA is proficiency testing. 

Cell Markers and Cytogenetics Committees College of American Pathologists. Clinical laboratory assays for HER-2/neu amplification and overexpression Quality assurance, standardization, and proficiency testing. Arch Pathol Lab Med. 2002 126 803-808. 

The Clinical Laboratory Improvement Amendments (CLIA) set standards designed to improve the quality of all laboratory testing. In the first portion of this chapter, we discuss the CLIA requirements that apply to most Immunohistochemistry laboratories, and explain topics such as certification, test complexity, patient test management, proficiency testing, personnel, quality control, quality assurance, and compliance. 

In general, the results of these proficiency testing programs indicate a considerable improvement in the performance of PbB determination in most laboratories (for review see Parsons, 1992). According to the practice in clinical chemistry, quality assurance including internal and external quality control should, therefore, be an integrated part of PbB measurements. 

Post-analytically, schemes are beginning to emerge specifically to compare practice and performance between laboratories pertaining to the interpretation of test results. For instance, in the UK, NEQAS in conjunction with the National Biochemical Genetic network, MetBio.Net, are offering a scheme that provides the opportunity, when given relevant clinical details, to interpret quantitative amino acid results. This proficiency scheme can compare interpretive skills without the need to circulate scarce clinical samples. 

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