Screening for dyslipidemia. Practice parameter.
Screening for serum lipid disorders is recommended by numerous specialty societies to identify patients at risk for coronary heart disease (CHD). The best screening tests will identify patients at highest risk for CHD who would benefit from intervention. This report discusses an appropriate test panel to use as the initial screen on a healthy outpatient population, and the required accuracy and precision of the tests from the Laboratory Medicine perspective. Controversy exists regarding which methods to use and at what age testing should begin. The following parameters will be modified as studies continue and new tests are developed. The recommendations are as follows: (1) Total serum cholesterol (TC) and high density lipoprotein-cholesterol (HDL-C) are presently the recommended screening tests for dyslipidemia in the general population; (2) The National Cholesterol Education Program (NCEP) recommends measuring TC and HDL-C in adults with a single sample at 5-year intervals beginning at age 20; (3) The NCEP recommends measuring TC in children with at least one parent having TC > or = 6.24 mmol/L (> or = 240 mg/dL); (4) The NCEP recommends a lipoprotein analysis consisting of a 12-hour fasting TC, HDL-C, triglyceride, and estimated low density lipoprotein-cholesterol (LDL-C) in adults with the following results: (a) TC > or = 6.24 mmol/L (> or = 240 mg/dL); (b) borderline TC of 5.20-6.23 mmol/L (200-239 mg/dL) and HDL-C < 0.91 mmol/L (< 35 mg/dL) or two or more risk factors; (c) desirable TC of < 5.20 mmol/L (< 200 mg/dL), but HDL-C < 0.91 mmol/L (< 35 mg/dL); (5) The NCEP recommends a lipoprotein analysis in children with documented CHD in a parent or grandparent, or in children that have a TC of > or = 5.20 mmol/L (> or = 200 mg/dL); (6) Two or three separate lipoprotein analyses should be done to confirm the LDL-C result before therapeutic intervention. Specimens should be tested from 1 to 8 weeks apart and the results averaged to account for physiologic variability; (7) Enzymatic methods are preferred for TC determination, and should be standardized and traceable to the reference method and materials at the Centers for Disease Control and Prevention (CDC); (8) The analytic method for TC should have a bias against the reference method of < 3% and a within laboratory reproducibility of < 3% coefficient of variation; (9) Chemical precipitation methods are preferred for HDL-C determination.(ABSTRACT TRUNCATED AT 250 WORDS)