A comparative study of the detergent-based method for estimating remnant lipoprotein cholesterol and the immunoseparation method

• Published in: Japanese Journal of Clinical Chemistry Vol. 36; no. 1; pp. 61 - 66
• Main Authors: Tanaka, Shinobu, Niwa, Yoshimasa, Okamoto, Yasuyuki, Haga, Yoshimasa
• Format: Journal Article
• Language: Japanese
• Published: Japan Society of Clinical Chemistry 2007; 一般社団法人 日本臨床化学会
• Subjects: apolipoprotein E; IDL; remnant-like particle cholesterol; VLDL; アポリポ蛋白E; レムナント様リポ蛋白コレステロール
• ISSN: 0370-5633; 2187-4077
• DOI: 10.14921/jscc1971b.36.1_61

Although the immunoseparation method is exclusively used to estimate remnant lipoprotein cholesterol as remnant-like particle cholesterol (RLP-C), a new detergent-based method has recently been developed and applied to a reagent for automated analyzer (RemL-C, Kyowa Medex Co.). Therefore, we conducted a comparative study of these two methods. Fifty-three serum samples and 41 other serum samples were used for the studies on correlation and precision, respectively. Apolipoprotein E (apoE)-deficient VLDL fraction isolated from VLDL fraction (d<1.006) by immunoseparation was used to study the effect of apoE elimination on determination. A strong linear correlation was found between RemL-C and RLP-C levels, and modeled with the following regression equation: RemL-C (mg/dL) = 0.853×RLP-C+3.18 (r=0.743). The average of differences between RemL-C and RLP-C indicated that RemL-C levels were generally higher. There were five discrepant cases in which the serum RemL-C level was 10mg/dL or more higher than the serum RLP-C level, all five were women, and all but one were pregnant. In contrast, there were two reversed discrepant cases that were both men, and both were elderly and had malignant tumors. Precision was inferior in RLP-C especially in the range of lower values. In apoE-deficient VLDL, the percentage of RemL-C/total cholesterol was similar to that in control VLDL, whereas the percentage of RLP-C/total cholesterol was lower than that in control VLDL. From these fi ndings, it is suggested that RemL-C and RLP-C have a similar clinical significance but show a different reactivity to some species of lipoprotein.