Three methods to determine low density lipoprotein cholesterol compared.

We have evaluated two precipitation methods to determine the low-density lipoprotein cholesterol in serum and an indirect method involving the Friedewald formula. This present study examines normo and hyper-triglyceridemic sera (less than 400 mg/dl; 4.52 mmol/l). regression analysis of the LDL-cholestserol values ascertained through polyvinsulfate precipitation (Y) versus the data calculated with the Friedewald formula (x) resulted in a good correlation (y=-0.49+1.04x; r=0.86; n=77). The mean of the PVS precipitation values was 138.6 mg/dl (3.58 mmol/l) and hence only 3.2% higher then the mean of the Friedewald method (134.2 mg/dl; 3.47 mmol/l). there was a satisfatctory correlation between the values obtained by amphipathic polymers precipitation (y) and those (x) of the Friedewald formula (y=17.53+0.80x; r=0.83; n=77). The LDL-chol/HDL-chol ratio was approximately 3 with 77 serum samples. The LDL chol/tot-chol X 100 was 64.8% (first method) and 60.2% (second method). The precipitation methods can therefore be used in clinical laboratories to mesure atherogenic low-density lipoproteins. However, when serum triglycerides and high-density lipoprotein cholesterol also are determined, the Friedewald formula is a reliable alternative. From our results, we conclude that the introduction of screening methods for specific precipitation of LDL is useful for epidemiological purposes or for selection of high-risk patients.