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Explore the world of laboratory tests and meet the experts, dive into analytical performance goals, and unravel the complex concepts behind clinical measurements. Discover strategies for setting quality specifications and gain insights into the reality of implementing these goals in practice. Access educational resources and stay informed about the latest developments in analytical quality and performance goals.
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All you wanted to know about laboratory tests, but were afraid to ask The informed patient meeting the laboratory director Analytical Performance Goals By Dietmar Stöckl STT Consulting - 9 -
Today All you wanted to know about laboratory tests -9-
The start • First general limits • Belk W, Sunderman FW. A survey of the accuracy of chemical analyses in clinical laboratories. Am J Clin Pathol 1947;17:853-61 (reprinted in: Arch Pathol Lab Med 1988;112:320-6). • First goals based on biology • Tonks DB. A study of the accuracy and precision of clinical chemistry determinations in 170 Canadian laboratories. Clin Chem 1963;9:217-33. • % maximum total error (TEmax) • = 100 * [¼ of the reference interval (RI)/mean of RI] • “If the normal range for sodium is taken to be 135-145 mEq./L., then the allowable limits of error calculated by this formula are ± 1.8%”. • “The maximum limits for any determination, however, were set at ± 10%, even though in some cases those calculated by the above formula exceeded this figure”. All you wanted to know about laboratory tests -9-
The concepts • The discipline agreed on the hierarchy of models for establishing analytical performance goals# • Clinical concepts • Questionnaires to clinicians • Concepts based on biological variation • Expert opinion/Regulations • "State-of-the-art" • #Kenny D, Fraser CG, Hyltoft Petersen P, Kallner A. Strategies to set global quality specifications in laboratory medicine, Stockholm, 24-26 April 1999. Consensus agreement. Scand J Clin Lab Invest 1999;59:585. All you wanted to know about laboratory tests -9-
The reality • Clinical concepts & questionnaires to clinicians • Few data available • Concepts based on biological variation • Start getting used by industry; misconception: values are for the laboratory, industry should use more stringent goals • Expert opinion/Regulations • Highly variable • "State-of-the-art“ • Difficult to assess; information typically restricted to imprecision (www.westgard.com; several essays on “Sigma analysis”) All you wanted to know about laboratory tests -9-
The reality • Typically, there is no consensus between (and often within) the different concepts • TEa ofserum sodium measurement All you wanted to know about laboratory tests -9-
Resources • Educational material • >www.stt-consulting.com • >Education • General • >Analytical quality II • TSH example • >Analytical performance goals TSH • Performance goals from biology • www.westgard.com/biodatabase1.htm All you wanted to know about laboratory tests -9-
I type ... ... more needs to be done. A lot to think about All you wanted to know about laboratory tests -9-
The next visit Performance assessment See you next time. All you wanted to know about laboratory tests -9-