|Clinical Use:||Apolipoprotein B can be used by clinicians for studies of cardiac risk factors in individuals with significant family histories of coronary artery disease or other increased risk factors; follow-up studies in individuals with abnormal LDL cholesterol values and also confirmation of suspected abetalipoproteinemia or hypobetalipoproteinemia|
|Background:||Apolipoprotein B (Apo B) is a major protein component of low-density lipoprotein (LDL) comprising >90% of the LDL proteins and constituting 20-25% of the total weight of LDL. Apo B exists in 2 forms. Apo B-100, the most abundant form of Apo B, is found in lipoproteins synthesized by the liver including LDL, VLDL, and IDL. Apo B-48 consists of the N-terminal 2152 amino acids (48%) of Apo B-100, is produced by the gut, and is found primarily in chylomicrons.Increased plasma concentration of Apo B-containing lipoproteins is associated with an increased risk of developing atherosclerotic disease. Case control studies have found plasma Apo B concentrations to be more discriminating than other plasma lipids and lipoproteins in identifying patients with coronary heart disease (CHD). Apo B measurement offers greater precision than LDL cholesterol determination which is most often derived by calculation.
Abetalipoproteinemia and severe hypobetalipoproteinemia can cause malabsorption of food lipids and polyneuropathy. In patients with hyperapobetalipoproteinemia (HALB), a disorder associated with increased risk of developing CHD and with an estimated prevalence of 30% in patients with premature CHD, Apo B is increased disproportionately in relation to LDL cholesterol. Apo B quantitation is required to identify these patients and is necessary in distinguishing HALB from another common lipoprotein abnormality, familial combined hyperlipidemia.
|Reference Ranges:||Female: 0.8 – 1.6 g/L|
|Patient Preparation:||None required|
|Specimen Requirements:||Serum – SST or Plain tube can be used|
|Turnaround Time:||6 weeks|
|Referred Test:||Referred test|
|Location:||Royal Victoria Infirmary|