The sd LDL-EX "SEIKEN" assay quantitatively determines small, dense low-dense lipoproteins (sd-LDL), a subfraction of LDL associated with an increased risk for cardiovascular disease (CVD). Past studies have shown that people with a predominance of sd-LDL (so called Pattern B patients) have a 3-fold increased risk of myocardial infarction (MI), while the relative risk is 4.5 for CAD and 7 for MI when sd-LDL levels are greater than 100mg/dL. Recent studies have also shown that a predominance of small dense LDL is a strong and independent risk factor of CHD and that there is a clear relationship between its levels and the severity of coronary heart diseases. Furthermore, the sd LDL-EX assay has great potential for standardization compared to current methods, which are disparate and require considerable technical expertise to perform. The patented assay methodology utilized consists of two steps: the first removes chylomicrons, VLDL, IDL, large LDL, and HDL using a surfactant and sphingomyelinase, and in the second step, a specific surfactant releases cholesterol only from the small, dense LDL particles for measurement by standard methods. The test is automatable on any standard clinical chemistry analyzer and gives results within 10 minutes.
NOTE: sd LD-EX "SEIKEN" is currently not available for sale in the United States.
- Development of novel homogeneous assay for sd-LDL (PDF 207 KB)
- Comparison of reference ranges for sd-LDL between the US and Japanese population (PDF 178 KB)
- sd-LDL Brochure (PDF 770 KB)
- 2006 AACC Presentation By Pacific Biometrics Inc (PDF 275 KB)
- From "The Fats of Life" Spring 2009 (PDF 1.6 MB)
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