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sdLDL (Small Dense LDL) (Direct)

Analyte: Small Dense LDL Cholesterol

Specimen Type: Serum, EDTA Plasma

Optimum Volume: 0.5 mL


2-8°C -20°C -70°C
7 days 1 month 3 years

Reporting units: mg/dL

Method: Colorimetric

Biological or Clinical Significance:

The sdLDL-C “Seiken” is a simple method for the quantitative determination of small, dense low density lipoprotein (LDL) cholesterol for research use only. LDL-cholesterol is a critical risk factor for developing coronary heart disease (CHD). Through several clinical investigations, it is now widely recognized that small, dense LDL, compared to the normal LDL, is more strongly associated with the development of CHD. It is reported that people with predominance of small, dense LDL have a 3-fold increased risk of myocardial infarction. Determination of sdLDL-C by ultracentrifugation, electrophoresis-based, or nuclear magnetic resonance methods are both laborious and time-consuming.

Principle of Test Method:

The sd-LDL-C assay is an automated colorimetric method with the sample pre-treatment to remove large, buoyant LDL and other apo B containing lipoproteins.


1. Koba S, Hirano T, Ito Y, Tsunoda R, Yokota Y, Ban Y, Iso Y, Suzuki H, Katagiri T. Significance of small dense low-density lipoprotein-cholesterol concentrations in relation to the severity of coronary heart disease. Atherosclerosis 2006; 189:206-214.
2. Hirano T, Ito Y, Saegusa H, Yoshino G. A novel and simple method for quantification of small, dense LDL. J Lipid Res 2003; 44:2193-2201.

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