Standardization is a needed step in building an effective quality-assurance system in laboratory testing. Quality laboratory performance (based on minimum performance standards) must be established before maintenance and control of long term quality laboratory testing can be ensured. To fulfill its commitment to improve the measurement of risk factors associated with cardiovascular disease, the Division of Laboratory Sciences (DLS) has focused on: 1) maintaining the highest quality lipid reference laboratory; and 2) offering standardization services through the Lipid Standardization Program (LSP) to federally funded and other public health heart-disease epidemiologic and research laboratories.
The goal of the LSP is to improve the laboratory measurement of cholesterol, triglycerides, high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) so they are measured with the accuracy and precision needed to reliably detect, treat, and prevent cardiovascular disease.
The LSP differs from typical proficiency testing programs in which clinical laboratories typically participate to meet federal regulatory requirements -- such as the Clinical Laboratory Improvement Amendments of 1988 (CLIA-88). The LSP is designed to improve a laboratory's analytical accuracy and precision performance by standardizing results over time and establishing a traceable link to the approved accuracy base at CDC. Proficiency testing programs, on the other hand, are based on peer grouping and provide no mechanism for establishing, assessing or improving accuracy. Such programs can evaluate only how well a laboratory carries out analytical testing in comparison to other laboratories using the same analytical systems and are not able to establish traceability to an accepted accuracy base.
The LSP is a rigorous three-part process designed so that each participating laboratory can achieve a standardized level of performance and validate traceability to a common reference point maintained by CDC. The standardization process requires laboratories to perform multiple analyses of CDC frozen-serum lipid reference materials that are prepared by pooling units from human donors collected to give specific lipid-concentration limits.
The CDC reference materials are provided to the laboratory as "unknowns," that is, the laboratory does not know the value of the lipid concentrations in the samples. Upon successfully completing all three parts of the program, a laboratory is considered to be standardized for measurement of the specified lipids. To maintain standardization performance, laboratories are monitored through quarterly analyses of selected panels of CDC test samples.
The LSP provides standardization services to over 100 participating laboratories, including international institutions.
