Are Measurements of LDL Particles Ready for Prime Time?(Editorials‪)‬

In this issue of Clinical Chemistry, Ensign et al. (1) report on the differences in 4 methods commonly used to assess LDL subfractions or particles. The results are both interesting and deeply disturbing. In a careful, well-planned study, Ensign and colleagues prospectively and simultaneously collected blood samples as required for each method. Sample analyses by 3 of the methods in question, nuclear magnetic resonance (NNIR), density gradient ultra-centrifugation (VAP), and gradient gel electrophoresis (GGE), were performed by the laboratories that developed and commercially offer these technologies. The fourth technique, tube gel electrophoresis (TGE), is sold as a commercial reagent set and was performed in the investigators' own laboratory according to the manufacturer's specifications. The primary result investigated was LDL pattern, as interpreted by the reporting laboratories. Other results reported by some of the laboratories included particle number/concentration and LDL cholesterol (LDL-C), the current focus of national and international treatment guidelines and therapeutic goals (2, 3).