Lipoprotein (a)
Label Mnemonic: LIPOA
Epic code: LAB3510
Downtime form: A-1a Doctor/Provider Orders - Pathology Core and Specialty Care Nursery
Commercial Mailout Laboratory
6240-8 RCP
356-8593
Specimen(s):
Serum
Specimen Instructions:
Patient must be fasting for 8-10 hours prior to draw.
Collection Medium:
and
Red top tube 5 mL (Clot Activator) Red top tube 5 mL (Clot Activator)
Minimum:
Collect in TWO full red top tubes.

Patient Preparation:
1. Fasting: 8 hours
2. Patient must abstain from alcohol for 24 hours before collection.
Delivery Instructions:
Deliver to laboratory immediately after collection.
Turn Around Time:
4 days upon receipt at reference laboratory (not reported on Saturday or Sunday).
Reference Range:
Lipoprotein (a) CHOLESTEROL: Normal: <5 mg/dL
 Lipoprotein-X: Undetectable
 Low-Density Lipoprotein Cholesterol (LDL-C):
  The National Lipid Association and the National Cholesterol Education Program
  (NCEP) have set the following guidelines for LDL-C in adults (ages 18 years
  and up):
    Desirable: <100 mg/dL
    Above desirable: 100-129 mg/dL
    Borderline high: 130-159 mg/dL
    High: 160-189 mg/dL
    Very high: > or =190 mg/dL

The Expert Panel on Integrated Guidelines for Cardiovascular Health and Risk Reduction in Children and Adolescents has set the following guidelines for LDL-C in children and adolescents (ages 2-17 years):
 Acceptable: <110 mg/dL
 Borderline high: 110-129 mg/dL
 High: > or =130 mg/dL
Interpretive Data:
Results of this panel can be used to determine the cholesterol content of low-density lipoprotein (LDL) and lipoprotein (a) (Lp[a]) separately. Interpretations of lipoprotein disorders can be made within the other clinical context.

Lipoprotein-X (LpX) is an abnormal lipoprotein that appears in the sera of patients with obstructive jaundice and is an indicator of cholestasis. The presence of LpX will be reported if noted during Lp(a) cholesterol analysis. The other values (LDL-C and Lp(a)-C) will not be reported if LpX is present.
Comments:
Useful For:
Evaluation of the contribution of lipoprotein (a) (Lp[a])-cholesterol within measured low-density lipoprotein cholesterol

Evaluation of increased risk for cardiovascular disease and events:
*Most appropriately measured in individuals at intermediate risk
 for cardiovascular disease

*Patients with early atherosclerosis or strong family history of
 early atherosclerosis without explanation by traditional risk
 factors should also be considered for testing

*Follow-up evaluation of patients with elevations in Lp(a) mass


Cautions:
Lipoprotein (a) (Lp[a]) cholesterol values should not be confused with Lp(a) mass values, although they may be correlated in some individual cases. Lp(a) cholesterol values will be approximately 10 times lower than Lp(a) mass values, but the difference between the measures is not uniform. Lp(a) mass values are considered elevated when greater than 30 mg/dL. Lp(a) cholesterol is increased if greater or equal to 5 mg/dL.

Intravenous administration of heparin causes activation of lipoprotein lipase, which tends to increase the relative migration rate of the fractions, especially beta lipoproteins.


Clinical Information:
The cholesterol within lipoprotein(a) (Lp[a]) is included in every method that measures low-density lipoprotein cholesterol (LDL-C). Therefore, in patients that express high concentrations of Lp(a) the interpretation of LDL-C and the resulting clinical diagnoses and treatment strategies may be inaccurate. This panel reports 3 values: 1) the cholesterol measured within LDL by beta quantitation (this result contains both LDL-C and Lp[a]), 2) the cholesterol within Lp(a), and 3) a calculated "true" LDL-C where Lp(a)-C is subtracted from the beta quantitation LDL-C.

The abnormal lipoprotein-X (LpX) is visible on lipoprotein electrophoresis. If LpX is present, the measurement of LDL-C is inaccurate and will not be reported.
Methodology:
Lipoprotein (a) Cholesterol: Electrophoresis/Enzyme Staining/Densitometry
Low-Density Lipoprotein Cholesterol: Ultracentrifugation/Selective Precipitation/Enzymatic Colorimetric (Beta-Quantification)
CPT Code:
83700, 83701