A modified total serum cholesterol method to eliminate the effect of high bilirubin levels.

TE”lTIE USE of dextrall sulfate has beell employed for the precipitation of serum $ iipoproteins (1). 1)allgerfield and Faulkner used dextran sulfate ill tile presence of calcium iOhlS to l)recipitate tue low-density lipoproteills (2). While investigating the precipitation properties of a large molecular weight dextran sulfate in the presence of calcium chloride, we obtained a precipitate from serum that appeared to contain the total serum cholesterol. It occurred to us that the iiicorporation of such a plPcil)itation step in the determination of serum cholesterol l)V a direct method, such as the Pearson et al. method (3), may eliminate errors due to high serum hilirubin. Although normal or slightly elevated levels of serum bilirubin have a negligible effect on cholesterol determinations, high levels pro(thee a considerable error. This study was initiated, therefore, too see if total cholesterol cai be precipitated from serum without coprecipitation of the hiliruhin.