Ten-year evaluation of homogeneous low-density lipoprotein cholesterol methods developed by Japanese manufacturers Application of the Centers for Disease Control and Prevention/Cholesterol Reference Method Laboratory Network lipid standardization protocol

• Published in: Journal of Atherosclerosis and Thrombosis Vol. 17; no. 12; pp. 1275 - 1281
• Main Authors: Nakamura, Masakazu, Koyama, Isao, Iso, Hiroyasu, Sato, Shinichi, Okazaki, Mitsuyo, Kayamori, Yuzo, Kiyama, Masahiko, Kitamura, Akihiko, Shimamoto, Takashi, Ishikawa, Yoshinori
• Format: Journal Article
• Language: English
• Published: Japan Japan Atherosclerosis Society 01.01.2010
• Subjects: Atherosclerosis - etiology; Bias; Cardiovascular Diseases - etiology; CDC/CRMLN; Centers for Disease Control and Prevention (U.S.); Cholesterol - blood; Cholesterol, LDL - blood; Cholesterol, LDL - standards; Follow-Up Studies; Humans; Japan; LDL-C; Metabolic syndrome; Metabolic Syndrome - complications; Predictive Value of Tests; Reference Standards; Reproducibility of Results; United States
• ISSN: 1340-3478; 1880-3873
• DOI: 10.5551/jat.5470

Aim: The risk index for atherosclerotic cardiovascular diseases in the Japanese metabolic syndrome-focused health checkup program was changed from total cholesterol (TC) to low-density lipoprotein cholesterol (LDL-C). We discuss the validity of this change with respect to standardization. Methods: The beta-quantification procedure of the Centers for Disease Control and Prevention (CDC) uses the LDL-C reference value as a target. Clinical laboratories and commercial manufactur-ers use homogeneous LDL-C methods for standardization. (A) For clinical laboratories, LDL-C in 648 samples requested from 108 hospitals was analyzed. (B) Manufacturers participated in the CDC/Cholesterol Reference Method Laboratory Network LDL-C standardization protocol. The standard-ization was conducted with a performance follow-up for the 10-year period from 1998 to 2008 at 2-year intervals, 6 times. Results: (A) In clinical laboratories, acceptable LDL-C levels within ±4% of the CDC's criteria re-mained 70.4%, 456 of 648 subjects. Negative maximum bias deviating from the LDL-C target value was -35.8%, -52.5 mg/dL, and positive maximum bias was +24.5%, +32.3 mg/dL. (B) For man-ufacturers, the standardization achievement rate of the analytical reagent/instrument/calibrator sys-tem in the last four standardizations from 2002 to 2008 remained on average 66.6%, far lower than the level required. Conclusions: The standardization achievement rate of homogeneous LDL-C methods was much low-er than that of TC. TC should still be used as a risk index for atherosclerotic cardiovascular diseases. The standardization achievement rate of homogeneous LDL-C should be maintained at 100%, at least using samples with normal lipoprotein profiles. The accuracy and specificity of LDL-C should be further improved before practical and clinical use.