Quantitation of Lp(a)
Lp(a) determination is intended for use in conjunction with clinical evaluation, patient risk assessment, and other lipid tests to evaluate disorders of lipid metabolism and to assess coronary heart disease in specific populations.
Intake of alcohol, aspirin, niacin, and estrogen supplements have the potential of causing a misrepresentation of true Lp(a) concentrations.
Immediately following collection, thoroughly mix sample by gently inverting 5 times
Gold serum separator (SST) tube
Dk green heparin (Li or Na), no gel
Lavender/Dk green/Lt blue:
Immediately following collection, mix sample thoroughly by gently inverting 8 - 10 times, to prevent clotting
Red:
Lavender/Dk green/Lt blue:
Refrigerated (preferred) – 14 days
Ambient – 14 days
Frozen – >14 days
Freeze/thaw cycles – stable x 3
Immunoturbidimetric
<75.0 nmol/L
Values ≥75.0 nmol/L may indicate independent risk factor for CHD.
Measurement of lipoprotein(a) is now recommended in several patient subgroups for whom excess lipoprotein(a) may have important clinical consequences: (1) patients with premature atherosclerosis, (2) patients with a strong family history of premature coronary heart disease (CHD), (3) patients with elevated LDL-C and greater than or equal to two risk factors, (4) patients who have had coronary angioplasty in whom lipoprotein(a) excess may increase the risk of restenosis, and (5) patients who have undergone coronary bypass graft surgery in whom Lp(a) excess may be associated with graft stenosis.
Lipoprotein(a) has been called a powerful predictor of premature atherosclerotic vascular disease. As an independent risk factor for premature coronary artery disease, excess Lp(a) concentrations are associated with an increased risk of cardiac death in patients with acute coronary syndromes and with restenosis after angioplasty (PTCA) and coronary bypass procedures. In general, concentrations greater than or equal to 75 nmol/L of Lp(a) in serum are associated with a two- to sixfold increase in risk, depending on the presence of other risk factors.