Test Details
Methodology
Immunoturbidimetric
Result Turnaround Time
2 - 4 days
Turnaround time is defined as the usual number of days from the date of pickup of a specimen for testing to when the result is released to the ordering provider. In some cases, additional time should be allowed for additional confirmatory or additional reflex tests. Testing schedules may vary.
Test Includes
Quantitation of Lp(a)
Use
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.
Limitations
Lp(a) is an independent risk factor for coronary artery disease and cerebral infarction (in white populations) equal to high LDL cholesterol. Serum concentrations are genetically determined. Fifteen percent to 20% of the white population have Lp(a) levels ≥75 nmol/L and are presumed to be at risk. Race-dependent differences in Lp(a) concentrations are known. Significance of high Lp(a) in nonwhite populations must be evaluated with caution.
The Lp(a) levels in different ethnic populations can vary widely. Africans, or people of African descent, generally have Lp(a) levels higher than Caucasians and Asians, while Native Americans generally have levels lower than Caucasians. This variability of Lp(a) levels by ethnic population requires careful interpretation of results based on a knowledge of the patient and other cardiac risk factors that may be present.1
Footnotes
Custom Additional Information
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.2,3
Lipoprotein(a) has been called a powerful predictor of premature atherosclerotic vascular disease.2 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.
Specimen Requirements
Specimen
Serum (preferred) or plasma
Volume
0.5 mL
Minimum Volume
0.2 mL
Container
Red-top tube, gel-barrier tube, lavender-top (EDTA) tube, green-top (heparin) tube, or blue-top (citrate) tube
Collection Instructions
Separate serum or plasma from cells as soon as possible (within two hours).
Stability Requirements
Temperature | Period |
|---|---|
Room temperature | 14 days |
Refrigerated | 14 days |
Frozen | 14 days |
Freeze/thaw cycles | Stable x3 |
Reference Range
<75.0 nmol/L; values ≥75.0 nmol/L may indicate independent risk factor for CHD.
Storage Instructions
Room temperature
Patient Preparation
Intake of alcohol, aspirin, niacin, and estrogen supplements have the potential of causing a misrepresentation of true Lp(a) concentrations.
Causes for Rejection
Grossly hemolyzed, lipemic, or icteric specimens
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 120188 | Lipoprotein (a) | 43583-4 | 120190 | Lipoprotein (a) | nmol/L | 43583-4 |
| Order Code | 120188 | |||||
| Order Code Name | Lipoprotein (a) | |||||
| Order Loinc | 43583-4 | |||||
| Result Code | 120190 | |||||
| Result Code Name | Lipoprotein (a) | |||||
| UofM | nmol/L | |||||
| Result LOINC | 43583-4 |