Apolipoprotein A1 and B, Serum

Test Code

APA1B

Alias/See Also

Epic: LAB3701
Mayo: APOAB

APOAB
Apo A
Apo A-I
Apo A1
Apo Al
Apo B
ApoA
ApoA-I
ApoA1
ApoAl
ApoB
Apolipoprotein A
Apolipoprotein A-I
Apolipoprotein A1
Apolipoprotein A1 and B-100, Plasma
Apolipoprotein AI
Apolipoprotein B
Apolipoprotein B-100
Apolipoprotein B/A1 ratio
Apolipoprotein B100
RBAA1

Includes

Test Id	Reporting Name	Available Separately	Always Performed
RBAA1	Apolipoprotein B/A1 ratio	No	Yes
APOA1	Apolipoprotein A1, S	Yes	Yes
APOLB	Apolipoprotein B, S	Yes	Yes

Preferred Specimen

Specimen Type: Serum
Collection Container: Serum gel
Specimen Volume: 1 mL

Minimum Volume

0.5 mL

Other Acceptable Specimens

Collection Container: Red top

Instructions

Centrifuge and aliquot 1 mL of serum.

Transport Container

Plastic vial

Specimen Stability

Specimen Type	Temperature	Time
Serum	Refrigerated (preferred)	8 days
	Frozen	60 days
	Ambient	24 hours

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Gross hemolysis	Reject
Gross lipemia	OK
Gross icterus	Reject

Methodology
Automated Turbidimetric Immunoassay

Setup Schedule

APOA1: Monday through Sunday

APOLB: Monday through Saturday

Report Available

1 to 3 days

Limitations

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

Reference Range

REFERENCE VALUES

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

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.

Clinical Significance

USEFUL FOR
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
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)

Performing Laboratory
Mayo Clinic Laboratories - Rochester
3050 Superior Drive NW
Rochester, MN 55901

Additional Information
Apolipoprotein A1 and B, Serum

Last Updated: December 18, 2023
Last Review: N. Wolford, December 18, 2023

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.