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

Test ID: APOAB    
Apolipoprotein A1 and B, Serum

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

Assessment of cardiovascular risk

 

Follow-up studies in individuals with basic lipid measures inconsistent with risk factors or clinical presentation

 

Definitive studies of cardiac risk factors in individuals with significant family histories of coronary artery disease or other increased risk factors

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

Apolipoprotein B (ApoB) is the primary protein component of low-density lipoprotein (LDL). Apolipoprotein A1 (ApoA1) is the primary protein component of high-density lipoprotein (HDL). Elevated ApoB and decreased ApoA1 are associated with increased risk of cardiovascular disease. Multiple studies have reported that ApoB and ApoA1 are more strongly associated with cardiovascular disease than the corresponding lipoprotein cholesterol fraction (see APOA1 / Apolipoprotein A1, Serum and APOLB / Apolipoprotein B, Serum).

 

ApoB is present in all atherogenic lipoproteins including LDL, Lp(a), intermediate-density lipoprotein (IDL), and very low-density lipoprotein (VLDL) remnants. ApoA1 is the nucleating protein around which HDL forms during reverse cholesterol transport. The ApoB:ApoA1 ratio represents the balance between atherogenic and antiatherogenic lipoproteins. Several large prospective studies have shown that the ApoB:ApoA1 ratio performs as well, and often better, than traditional lipids as an indicator of risk.(1-3)

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.

Males

Age

Apolipoprotein A (mg/dL)

Apolipoprotein B (mg/dL)

Apolipoprotein B/A1 ratio

<24 months

Not established

Not established

Not established

2-17 years

Low: <115

Borderline low: 115-120

Acceptable: >120

Acceptable: <90

Borderline high: 90-109

High: > or =110

<0.8

>18 years

> or =120

Desirable: <90

Above Desirable: 90-99

Borderline high: 100-119

High: 120-139

Very high: > or =140

 

Lower Risk: <0.7

Average Risk: 0.7-0.9

Higher Risk: >0.9

Females

Age

Apolipoprotein A (mg/dL)

Apolipoprotein B (mg/dL)

Apolipoprotein B/A1 ratio

<24 months

Not established

Not established

Not established

2-17 years

Low: <115

Borderline low: 115-120

Acceptable: >120

Acceptable: <90

Borderline high: 90-109

High: > or =110

<0.8

>18 years

> or =140

Desirable: <90

Above Desirable: 90-99

Borderline high: 100-119

High: 120-139

Very high: > or =140

 

Lower Risk: <0.6

Average Risk: 0.6-0.8

Higher Risk: >0.8

Interpretation Provides information to assist in interpretation of the test results

Elevated apolipoprotein B (ApoB) confers increased risk of atherosclerotic cardiovascular disease, even in a context of acceptable LDL cholesterol concentrations.

 

Extremely low values of ApoB (<48 mg/dL) are related to malabsorption of food lipids and can lead to polyneuropathy.

 

Reduced apolipoprotein A1 (ApoA1) confers an increased risk of coronary artery disease. Extremely low ApoA1 (<20 mg/dL) is suggestive of liver disease or a genetic disorder.

 

Elevated ApoB:ApoA1 ratio confers increased risk of atherosclerotic cardiovascular disease, independently of LDL and HDL cholesterol concentrations.

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

In very rare cases, gammopathy, in particular type IgM (Waldenstrom macroglobulinemia), may cause unreliable results.

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

1. Reiner Z, Catapano AL, De Backer G, et al: ESC/EAS Guidelines for the management of dyslipidaemias: The task force for the management of dyslipidaemias of the European Society of Cardiology (ESC) and the European Atherosclerosis Society (EAS). Eur Heart J 2011;32(14):1769-1818

2. McQueen MJ, Hawken S, Wang X, et al: Lipids, lipoproteins, and apolipoproteins as risk markers of myocardial infarction in 52 countries (the INTERHEART study): a case-control study. Lancet 2008;372:224-233

3. Thompson A, Danesh J: Associations between apolipoprotein B, apolipoprotein AI, the apolipoprotein B/AI ratio and coronary heart disease: a literature-based meta-analysis of prospective studies. J Intern Med 2006;259:481-492

4. Jacobson TA, Ito MK, Maki KC, et al: National Lipid Association recommendations for patient-centered management of dyslipidemia: Part 1-executive summary. J Clin Lipidol 2014 Sep-Oct;8(5):473-488

5. Expert panel on integrated guidelines for cardiovascular health and risk reduction in children and adolescents: summary report. Pediatrics 2011 Dec;128 Suppl 5:S213-S256