TEST CATALOG ORDERING & RESULTS SPECIMEN HANDLING CUSTOMER SERVICE EDUCATION & INSIGHTS
Test Catalog

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

Useful For Suggests clinical disorders or settings where the test may be helpful

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

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

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 Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

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

Interpretation Provides information to assist in interpretation of the test results

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 Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

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.

Supportive Data

Interpretation of low-density lipoprotein cholesterol (LDL-C) can be confounded in cases with elevated lipoprotein (a) (Lp[a]) expression because the cholesterol within Lp(a) is usually indistinguishable from the cholesterol within LDL. Accurate LDL-C measurements are critical for identifying genetic dyslipidemias such as familial hypercholesterolemia (FH). The interpretation of LDL-C, particularly in FH diagnostic algorithms may be affected by Lp(a)-C content.(1). Therefore, this panel reports the total measured LDL-C, the Lp(a)-C, and the LDL-C corrected for Lp(a)-C content.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Fatica EM, Meeusen JW, Vasile VC, Jaffe AS, Donato LJ. Measuring the contribution of Lp(a) cholesterol towards LDL-C interpretation. Clin Biochem. 2020 Dec;86:45-51. doi: 10.1016/j.clinbiochem.2020.09.007. Erratum in: Clin Biochem. 2021 Feb;88:56-57

2. Willeit P, Yeang C, Moriarty P, et al: Low-density lipoprotein cholesterol corrected for lipoprotein (a) cholesterol, risk thresholds, and cardiovascular events. J Am Heart Assoc. 2020 Dec;9(23):e016318

3. Yeang C, Witztum JL, Tsimikas S: 'LDL-C'?=?LDL-C?+?Lp(a)-C: implications of achieved ultra-low LDL-C levels in the proprotein convertase subtilisin/kexin type 9 era of potent LDL-C lowering. Curr Opin Lipidol. 2015 Jun;26(3):169-178. doi: 10.1097/MOL.0000000000000171

4. Kinpara K, Okada H, Yoneyama A, Okubo M, Murase T: Lipoprotein(a)-cholesterol: a significant component of serum cholesterol. Clin Chim Acta. 2011 Sep 18;412(19-20):1783-1787. doi: 10.1016/j.cca.2011.05.036

5. Yeang C, Willeit P, Tsimikas S: The interconnection between lipoprotein(a), lipoprotein(a) cholesterol and true LDL-cholesterol in the diagnosis of familial hypercholesterolemia. Curr Opin Lipidol. 2020 Dec;31(6):305-312. doi: 10.1097/MOL.0000000000000713