Proficiency Analytical Testing Program

Figure 4 is a spectrum of a filter from the Proficiency Analytical Testing Program (PAT) conducted by the National Institute of Occupational Safety and Health (NIOSH) which contained 103 micrograms as determined by this lab. PAT filters are prepared with 2 mg of sodium silicate as a contaminant. A baseline approximation as described fo Figure 1 is not possible due to the interfering peak at 845 cm. When a spectrum of this type is encountered, a line is drawn from the two minimums on either side of the quartz doublet peak as illustrated by the dotted line in Figure 4. 

NIOSH Chemical Reference Laboratory Proficiency Analytical Testing Program, National Instimte for Occupational Safety and Health (NIOSH) Publication No. 79-128, Cincinnati, 1979. 

Each laboratory engaged in asbestos counting shall participate in the Proficiency Analytical Testing Program, the / bestos Analyst Registry or equivalent. 

At this time, there is no known method to determine the absolute accuracy of the asbestos analysis. Results of samples prepared through the Proficiency Analytical Testing (PAT) Program and analyzed by the OSHA-SLTC showed no significant bias when compared to PAT reference values. The PAT samples were analyzed from 1987 to 1989 (N=36) and the concentration range was from 120 to 1,300 fibers/mm. ... 

Participation in interlaboratory comparisons and proficiency-testing programs provides additional information especially pertinent to controlling interlaboratory variation. Aliquots of homogeneous samples containing the analytes of interest are drawn and distributed to each participating laboratory. The participants results are used to calculate overall and method-specific statistics, such as means, medians, and standard devia-... 

Traceability of analytical results to a proficiency testing program... 

There will often be a problem with the similarity/suitability of a proficiency test program in relation to the level at which work is usually carried out in a laboratory. If the difference is too great, traceability can no longer be claimed. It may either be the matrix that is not quite agreeable or the concentration of the analyte is at the wrong level. 

Initial method evaluation studies are essential to ensure that systematic errors are not present before the baseline period and the determination of the mean and the control limits. The accuracy of the method should be initially established by comparison with other analytical methods (and recovery and interference studies) and should continue to be monitored by comparison with other analytical methods. Ongoing comparison-of-methods studies are desirable to ensure that systematic errors do not slowly increase and go undetected by internal QC procedures. These ongoing comparison studies are provided by the external QA programs, which in turn form the basis for proficiency testing programs. 

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,... 

In a survey of analysts the top rating indicators of quality were the use of validated methods and the use of reference materials followed by participation in proficiency testing and quality audits. The Valid Analytical Measurement program of the Laboratory of the Government Chemist in the UK lists six aspects of a quality laboratory that mirrors the list given above ... 

Over the past decade, a major trend has been the development of the use of proficiency testing (PT) or evaluation materials (Fox 2000). PT materials are a type of reference material, which aid in assessment of analytical laboratory measurement quality. There will be an increased use of such materials as part of laboratory accreditation programs and other new quality assurance efforts, including internal audits. At the same time, a number of providers have used PT schemes to produce a form of RM intended to meet the ever-growing need for RMs required for routine QC use (Jenks 1995,1997). 

The Technical Services function of AOCS establishes, revises, and annually updates AOCS Methods, the Official Methods and Recommenced Practices of the American Oil Chemists Society22 for fats, oils, and soap technology Spanish AOCS Methods, a Spanish translation of the more commonly used AOCS Methods and Physical and Chemical Characteristics of Oils, Fats and Waxes. Leaders of the methods development committees coordinate closely with AOAC International (formerly the Association of Official Analytical Chemists). AOCS Methods are recognized as Official Methods in US FDA activities and when litigation becomes necessary in industry trade. Additionally, the Technical Services function operates a Laboratory Proficiency Program (formerly the Smalley Check Sample Program) and oversees distribution and statistical analysis of 30 different series of basic laboratory quality assur-ance/quality control test samples. Certification as AOCS Approved Chemists, or as AOCS... 

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. 

One other development in support of analytical data quality must be mentioned, namely the use of round robin analysis, which has developed into a number of laboratory performance assessment programs, and also known as proficiency-testing schemes. A proficiency-testing scheme does not eliminate the need for a quality system. In fact, the scheme can at best provide only a snapshot of how a laboratory was performing on particular analyses on one occasion. Moreover, such schemes still exist only for a fairly limited range of sample and analyte combinations. 

A proficiency test was carried out recentiy to assess the performance of MinUab visual TLC quantification estimates.Samples were made at 0%, 40%, and 100% from a dmg reference tablet and given, unidentified, to inspectors with the Minilab protocol for quality screening. In round 1 of the proficiency test, only 3 of 28 substandard samples were correctly identified. Round 2, administered after a performance qualification test for the analytical method, showed improvement 19 of 27 substandard dmgs were correctly identified, while 5 out of 9 inspectors made the correct inference on the quality of 45 samples. In both rounds, two inspectors failed to identify substandard samples. These results show the need to have competent, well-trained users and to include a proficiency test in the Minilab screening program to obtain reliable results. 

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