Evaluation of a simple method for measuring blood cholesterol levels using non-laboratory observers

Blood cholesterol is a good estimator of risk for coronary heart disease. Six criteria for a screening cholesterol measurement are: (1) high predictive value of elevated cholesterol compared with a "gold standard" cholesterol measurement; (2) high correlation with the national reference system for cholesterol; (3) acceptable results obtainable by volunteer observers; (4) results available quickly; (5) reproducible results; and (6) low cost. We hypothesized that cholesterol measurements performed on the Reflotron by volunteer nurses would meet these criteria.

We recruited 345 subjects (160 men, 185 women, aged 20 to 84) and measured their blood cholesterol level by a method calibrated under the National Heart, Lung, and Blood Institute Lipid Standardization Program (Lab-chol) and on the Reflotron (R-chol method).

Comparison of the results showed good agreement (slope = 0.937; intercept = 0.27 mmol/liter). Comparison of the risk assignments made by the R-chol method against those made by the Lab-chol method, using the 1987 Adult Treatment Panel classification criteria, showed that the R-chol method has a sensitivity of 0.79 and a specificity of 0.98. Assuming a national prevalence of hypercholesterolemia of 25 percent, the positive predictive value is 0.92 and the negative predictive value is 0.93. The cost per screen was $1.25.

These data show that volunteer observers can obtain screening cholesterol results on the Reflotron that are accurate, reliable, quickly available at a low cost, and have high predictive value for hypercholesterolemia.