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Test Code LPALD Lipoprotein (a) and Low-Density Lipoprotein Cholesterol, Serum


Specimen Required


Patient Preparation:

1. Fasting (8 hours) required

2. Patient must abstain from alcohol for 24 hours before collection.

Supplies: Sarstedt Aliquot Tube, 5 mL (T914)

Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 4 mL

Collection Instructions:

1. Centrifuge and aliquot serum into a plastic vial.

2. Send refrigerated.


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

Method Name

Lipoprotein (a) Cholesterol: Electrophoresis/Enzyme Staining/Densitometry

Low-Density Lipoprotein Cholesterol: Ultracentrifugation/Selective Precipitation/Enzymatic Colorimetric (Beta-Quantification)

Reporting Name

Lp(a) and LDL Cholesterol, S

Specimen Type

Serum

Specimen Minimum Volume

2 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 7 days
  Frozen  60 days

Reject Due To

Gross hemolysis Reject
Gross lipemia OK
Gross icterus Reject
 

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.

Reference Values

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 older):

Desirable: <100 mg/dL

Above desirable: 100-129 mg/dL

Borderline high: 130-159 mg/dL

High: 160-189 mg/dL

Very high: ≥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: ≥130 mg/dL

Interpretation

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.

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.

Day(s) Performed

Monday through Thursday, Sunday

Report Available

3 to 4 days

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Test Classification

This test has been modified from the manufacturer's instructions. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

83700

83701

LOINC Code Information

Test ID Test Order Name Order LOINC Value
LPALD Lp(a) and LDL Cholesterol, S 100732-7

 

Result ID Test Result Name Result LOINC Value
2849 Lp(a) Cholesterol 35388-8
23924 LpX 42178-4
614917 LDL Chol (Beta-Quantification), S 18261-8
610767 LDL-C Corrected for Lp(a)-C 100733-5

Forms

If not ordering electronically, complete, print, and send a Cardiovascular Test Request Form (T724) with the specimen.