Evaluation of an HPLC method for LDL-cholesterol determination in patients with various lipoprotein abnormalities in comparison with beta-quantification.

BACKGROUND

The main purpose of this study was to evaluate an HPLC method for LDL-cholesterol determination in the presence of abnormal lipoproteins.

METHODS

We compared LDL-cholesterol levels obtained by HPLC (HPLC-LDL), Friedewald (F-LDL), and beta-quantification (BQ-LDL) methods on 47 healthy volunteers and 50 outpatients with lipid disorders, including apolipoprotein E2/2 phenotype, cholesteryl ester transfer protein deficiency and lipoprotein lipase deficiency.

RESULTS

For the control group (n=50), the HPLC-LDL and the F-LDL correlated highly with the BQ-LDL (r=0.984 and 0.969, respectively), but the HPLC-LDL was lower than the BQ-LDL (mean bias: -4.0%, P<0.001). For the subjects with lipoprotein abnormalities, significant biases were found in HPLC-LDL for the hypertriglyceridemia (+25%, n=17, P<0.01), the hyper HDL (-15.2%, n=10, P<0.01) and the hyper lipoprotein(a) groups (-13.4%, n=12, P<0.001). The F-LDL was significantly higher than the BQ-LDL in the apolipoprotein E2/2 subjects (+92%, n=8, P<0.001), but not significantly different in other subjects with triglycerides <4000 mg/l.

CONCLUSIONS

There were several discrepancies in LDL-cholesterol levels determined by the HPLC and the BQ methods in samples with lipoprotein abnormalities. However, the HPLC method can be useful and informative for analysis of abnormal lipoproteins.