Test Accuracy and Factors That Influence Cholesterol Levels
PEMD-95-8: Published: Dec 30, 1994. Publicly Released: Feb 14, 1995.
- Full Report:
Pursuant to a congressional request, GAO reviewed the National Heart, Lung, and Blood Institute's National Cholesterol Education Program (NCEP), focusing on the: (1) different techniques for measuring cholesterol in laboratory settings; (2) accuracy of these measurement techniques; (3) factors that influence individual cholesterol levels; and (4) potential effect of cholesterol measurement variability.
GAO found that: (1) the natural daily variation in cholesterol levels and instrument measurement errors make it impossible to pinpoint individual cholesterol levels; (2) over 160 different devices with different technologies and chemical formulations are available to perform cholesterol tests; (3) standard cholesterol tests measure two cholesterol components, total cholesterol, and a related blood fat; (4) research, clinical, and hospital laboratories tend to produce reasonably accurate and precise cholesterol measurements, but little is known about cholesterol measurements in other settings such as physicians' offices and public health screenings; (5) two federal agencies have developed reference methods and quality control testing materials for manufacturers and laboratories to use in assessing their equipment's performance; (6) although cholesterol measurement methods have improved in recent years, there is a large variance in the accuracy and precision of tests performed across a broad range of devices and analytical settings; (7) there has been no overall evaluation of the different instruments and technologies laboratories use to conduct cholesterol tests; (8) biological and behavioral factors, many of which are uncontrollable, cause individual cholesterol levels to vary and may account for up to 65 percent of total variation in individual cholesterol levels; (9) the methods for collecting and handling blood specimens affect cholesterol measurements; and (10) uncertain cholesterol measurements can affect individual diagnoses and treatment decisions.