Purpose:
Contemporary cholesterol screening has involved capillary and venous samples with capillary cholesterol screening typically drawing blood from the tip of the finger while venous samples are drawn from the antecubital vein found in the bend of the elbow. Studies have compared capillary blood and its accuracy predicting cholesterol levels to the use of venous blood. Total cholesterol, risk ratio cholesterol, HDL-C and LDL-C, which are measured from venous samples, are considered more precise than a capillary sample. The purpose of this study was to compare total capillary, total venous, risk ratio, HDL-C and LDL-C measures of cholesterol to discover if total capillary cholesterol is a valid measure to use in cholesterol screening.
Design:
An announcement and a registration form were distributed with employee paychecks announcing a cholesterol screening program. Capillary and venous samples were collected from screening participants (N=285).
Results:
LDL-C and HDL-C helped to identify increased risk participants 34.4% and 14.4% more often than total capillary cholesterol respectively. Risk ratio (inclusion of HDL-C) helped to identify increased risk participants 23.9% more often than total capillary cholesterol. Total venous cholesterol identified increased risk participants 17.2% of the time when compared to capillary total cholesterol. Total venous cholesterol measurement performed much better when compared to risk ratio and HDL-C yet still contained some false negatives (6.7%-risk ratio, 2.6% HDL-C). A paired t-Test for variance between groups revealed significant differences in total capillary cholesterol and venous total cholesterol values (t=-41.93, p< .0000).
Conclusions:
Total capillary cholesterol had false negatives 17.21%-34.4% of the time when compared to the other methods of cholesterol measurement. The literature suggests risk ratio with inclusion of HDL-C and LDL-C are the most valid lipid predictors of coronary heart disease risk and findings of this project agree. LDL-C has been identified by the NCEP as the cholesterol component that should be lowered to decrease risk for heart disease. Using LDL-C as a measure of prediction of risk or referral when compared to total capillary cholesterol demonstrated the major shortcomings of total capillary cholesterol. Due to the high number of misclassifications, total capillary cholesterol does not seem to be a valid predictor of risk for heart disease, or a valid measure to use for referral. Risk ratio, HDL-C, and LDL-C seem to identify more people at risk for cardiovascular disease, eliminating total capillary cholesterol as viable means of increased risk prediction and referral.