Analysis of alpha-lipoprotein cholesterol in 50 microl of plasma

A micromethod for quantitation of alpha-lipoprotein cholesterol was devised for gas-liquid chromatography to minimize plasma sample size and facilitate lipid studies using capillary blood from children or small animals. alpha-Lipoprotein cholesterol was measured by gas-liquid chromatography in 20 micro l of the centrifuged supernate obtained after addition of 5 micro l of mixed heparin-manganese chloride solution 1:1 (v/v) to 50 micro l of plasma. Comparison of venous alpha-lipoprotein cholesterol measured by gas-liquid chromatography with venous alpha-lipoprotein cholesterol measured by conventional heparin-manganese precipitation and ferric chloride (colorimetric) cholesterol determination gave a correlation coefficient of 0.98 for 80 plasma samples. Capillary alpha-lipoprotein cholesterol and venous alpha-lipoprotein cholesterol were closely correlated in 31 patients (r = 0.97).