Homogeneous Assays for LDL-C and HDL-C are Reliable in Both the Postprandial and Fasting State.
OBJECTIVE
Most epidemiological and clinical studies calculated low-density lipoprotein-cholesterol (LDL-C) by Friedewald's formula which cannot be used in the postprandial samples. Although the homogeneous assays with poor analytical performance were withdrawn from the market, it remained unclear whether the currently available reagents for LDL-C and high-density lipoprotein-cholesterol (HDL-C) are as accurate for postprandial samples as for fasting samples.


METHODS
Fresh blood samples were collected from 59 non-diseased and 109 diseased subjects. Postprandial samples constituted 72.9% and 39.4% of these samples. LDL-C and HDL-C concentrations were measured using the homogeneous assays of four manufacturers (Denka Seiken, Wako, Kyowa Medex, and Sekisui Medical). Simultaneously, LDL-C and HDL-C concentrations were determined using the reference measurement procedures (RMPs) of the Centers for Disease Control and Prevention (CDC). Total errors were calculated using a routine method (TEcom) and via error component analysis (TEECA).


RESULTS
All homogeneous assays for LDL-C and HDL-C met the National Cholesterol Education Program (NCEP) requirements in terms of coefficient of variation, and TEcomin both non-diseased and diseased subjects. LDL-C and HDL-C values measured by the homogeneous assays were in good agreement with those measured by the RMPs in both fasting and postprandial samples. The TEcomand TEECAvalues of the postprandial samples were similar to those of fasting samples, although the TEECAvalues were up to 4.4-fold greater than the TEcomvalues.


CONCLUSIONS
In both non-diseased and diseased subjects, the homogeneous assays for LDL-C and HDL-C of four manufacturers are as accurate for postprandial samples as for fasting samples.
Department of Clinical Laboratory Medicine, Juntendo University Graduate School of Medicine.
Takashi
T
Miida
Department of Preventive Medicine and Epidemiologic Informatics, National Cerebral and Cardiovascular Center.
Kunihiro
K
Nishimura
Department of Clinical Laboratory Medicine, Juntendo University Graduate School of Medicine.
Satoshi
S
Hirayama
Department of Preventive Cardiology, Department of Preventive Medicine and Epidemiologic Informatics, National Cerebral and Cardiovascular Center.
Yoshihiro
Y
Miyamoto
Department of Preventive Cardiology, Lipid Reference Laboratory, National Cerebral and Cardiovascular Center.
Masakazu
M
Nakamura
Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine.
Daisaku
D
Masuda
Department of Cardiovascular Medicine, Osaka University Graduate School of Medicine.|Rinku General Medical Center.|Department of Community Medicine, Osaka University Graduate School of Medicine.
Shizuya
S
Yamashita
Clinical Laboratory, University Hospital, Kyoto Prefectural University of Medicine.
Masaji
M
Ushiyama
Clinical Laboratory, University Hospital, Kyoto Prefectural University of Medicine.
Toshiaki
T
Komori
Department of Infection Control and Laboratory Medicine, Kyoto Prefectural University of Medicine.
Naohisa
N
Fujita
Department of Food and Nutritional Sciences, Practice Center for Registered Dietitian, Chubu University.
Shinji
S
Yokoyama
Teikyo Academic Research Center, Teikyo University.
Tamio
T
Teramoto
D000328:Adult; D000368:Aged; D002138:Calibration; D016022:Case-Control Studies; D008076:Cholesterol, HDL / Q000097:blood*; D008078:Cholesterol, LDL / Q000097:blood*; D019411:Clinical Laboratory Techniques; D005215:Fasting; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D010045:Outpatients; D019518:Postprandial Period; D015203:Reproducibility of Results; D014280:Triglycerides / Q000378:metabolism
D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D014280:Triglycerides
Cholesterol Reference Method Laboratory Network (CRMLN); Direct assay; Dyslipidemia; Friedewald's formula; Standardization