Apolipoprotein A-1

Latest Edit: Hector 2014-03-21 (EDT)

See Also	Lab Tests

Apolipoproteins are a protein component of lipoprotein complexes. Apolipoprotein A-1 (Apo A) is the major component of HDL, while Apolipoprotein B is the major component of LDL.,

Discussion

Apolipoprotein A1 is greater predictor for lower incidence of cardiovascular disease than HDL alone. Apolipoprotein A1 activates the enzymes that load cholesterol from the tissues into HDL and allows HDL to effectively get rid of the excess cholesterol at the tissue level. Deficiencies in apolipoprotein A1 are associated with increased risk of cardiovascular disease as the cholesterol is not transported back to the liver.

• Apolipoprotein A1 is often ordered if there is a family history of myocardial infarction in young men in order to determine a person's risk.
• Apolipoprotein B have been found to be associated with an increased risk of atherosclerotic coronary artery disease.

Patient Preparation

• Patient must fast for 12- 14 hours before testing. Water is permitted.
• Smoking is prohibited.

• Factors which can cause increased levels:

• physical exercise
• Drugs: carbamazepine, estrogens, ehtanol, lovastatin, niacin, oral contraceptives, phenobarbital, pravastatin, and simvastatin

• Factors which can cause decreased levels:

• diet high in polyunsaturated fats, smoking
• Drugs: oral contraceptive use, androgens, beta blockers, diuretics, and progestins

Clinical Implications

• High levels indicate:

• lowered incidence of cardiovascular disease

• Low levels indicate:

• increased incidence of premature cardiovascular disease. It is also associated with poorly controlled diabetes, hepatocellular disease, nephrotic syndrome and renal failure.

Associated Tests

The tests that are often run in conjunction with Apo A-1 includes Apolipoprotein B, Triglycerides, cholesterol, LDL, HDL, VLDL, Uric acid, Lipid electrophoresis, RBC, HCT, and HGB