Reference standardization and triglyceride interference of a new homogeneous HDL-cholesterol assay compared with a former chemical precipitation assay

¹ Academic Hospital Rotterdam, 3015 GD Rotterdam, The Netherlands.

² Istituto Scientifico H.S. Raffaele, Milan, Italy.

³ Klinikum Grosshadern, Munich, Germany.

⁴ Klinikum der Universität des Saarlandes, Hamburg, Germany.

⁵ Boehringer Mannheim, Mannheim, Germany.

⁶ Klinikum der Universität, Freiburg, Germany.
^a Address correspondence to this author at: Department of Clinical Chemistry, Lipid Reference Laboratory, Academic Hospital Rotterdam, Dr. Molewaterplein 40, 3015 GD Rotterdam, The Netherlands. Fax 31-10 436 7894; e-mail: boersma{at}ckcl.azr.nl.

A homogeneous HDL-c assay (HDL-H), which uses polyethylene glycol-modified enzymes and sulfated -cyclodextrin, was assessed for precision, accuracy, and cholesterol and triglyceride interference. In addition, its analytical performance was compared with that of a phosphotungstic acid (PTA)/MgCl₂ precipitation method (HDL-P). Within-run CVs were 1.87%; total CVs were 3.08%. Accuracy was evaluated in fresh normotriglyceridemic sera using the Designated Comparison Method (HDL-H = 1.037 Designated Comparison Method + 4 mg/L; n = 63) and in moderately hypertriglyceridemic sera by using the Reference Method (HDL-H = 1.068 Reference Method - 17 mg/L; n = 41). Mean biases were 4.5% and 2.2%, respectively. In hypertriglyceridemic sera (n = 85), HDL-H concentrations were increasingly positively biased with increasing triglyceride concentrations. The method comparison between HDL-H and HDL-P yielded the following equation: HDL-H = 1.037 HDL-P + 15 mg/L; n = 478. We conclude that HDL-H amply meets the 1998 NCEP recommendations for total error; its precision is superior compared with that of HDL-P, and its average bias remains below ±5% as long as triglyceride concentrations are 10 g/L and in case of moderate hypercholesterolemia.

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