Apolipoprotein B
(Specimen Container)
SST (Tiger Top)
Lithium Heparin/ Sodium Heparin/ EDTA
(Transport Temperature)
| Temperature | Period |
|---|---|
| Room temperature | 3 days |
| Refrigerated | 7 days |
| Frozen | 3 months |
Lipids that are synthesized in the intestine or liver need to be transported to tissues and organs for their varied metabolic functions. Given the hydrophobic nature of the neutral fats, triglycerides, and cholesterol esters, lipid transport and delivery via plasma would not be possible without some form of hydrophilic adaptation. Lipids are transported by means of a series of micellar structures known as lipoproteins that consist of an outer monolayer of protein (apolipoprotein) and polar lipids, and an inner core of neutral lipids. ApoB is the major protein moiety of all lipoproteins other than HDL, and exists in two major forms; ApoB48 and ApoB100. ApoB48 is synthesized in the intestine and is present on chylomicrons and their remnants. ApoB100 is synthesized in the liver and is present on VLDL, IDL, and LDL. The structure of ApoB48 is the same as the N-terminal 48% of ApoB100. The basic biochemistry and clinical importance of ApoB have both been active areas of research. Therefore, a large body of information has been established regarding its synthesis, assembly into lipoproteins, and the atherogenic actions of ApoB-containing lipoproteins such as VLDL and LDL. LDL, which contains a single copy of the ApoB100 molecule, transports lipids into cells by binding to LDL-receptors present on the surface of most cells. Accumulation of excess intracellular lipids can result in atherosclerotic vascular disease. Also, genetic defects in the LDL-receptor itself causes familial hypercholesterolemia, which results in atherosclerosis early in life. Numerous studies have demonstrated the diagnostic value of Apolipoprotein analysis. An international group of collaborators has stated, “ApoB has been shown to be superior to LDL cholesterol in predicting the risk of vascular events and the progression of vascular disease in a series of prospective epidemiological studies”. In relation to use of the ApoB/ApoA-I ratio, they state that the ApoB/ApoA-I ratio was more informative of cardiovascular risk than the conventional indices: total cholesterol/HDL-C, LDL-C/HDL-C or non-HDL-C/LDL/C.ApoB measurements are useful in the diagnosis of premature coronary artery disease, hyper-β-lipoproteinemia, and hypo-β-lipoproteinemia.
<90 mg/dL
