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HelpTest Code APOAB Apolipoprotein A1 and B, Serum
Specimen Required
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions: Centrifuge and aliquot 1 mL of serum.
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
Profile Information
| 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 |
Method Name
Automated Turbidimetric Immunoassay
Reporting Name
Apolipoprotein A1 and B, SSpecimen Type
SerumSpecimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 8 days | |
| Frozen | 60 days | ||
| Ambient | 24 hours |
Reject Due To
| Gross hemolysis | Reject |
| Gross lipemia | OK |
| Gross icterus | Reject |
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)
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: ≥110 |
<0.8 |
|
>18 years |
≥120 |
Desirable: <90 Above Desirable: 90-99 Borderline high: 100-119 High: 120-139 Very high: ≥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: ≥110 |
<0.8 |
|
>18 years |
≥140 |
Desirable: <90 Above Desirable: 90-99 Borderline high: 100-119 High: 120-139 Very high: ≥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.
Day(s) Performed
APOA1: Monday through Sunday
APOLB: Monday through Saturday
Report Available
1 to 3 daysSpecimen Retention Time
1 weekPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
82172 x 2
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| APOAB | Apolipoprotein A1 and B, S | 55724-9 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| APOLB | Apolipoprotein B, S | 1884-6 |
| APOA1 | Apolipoprotein A1, S | 1869-7 |
| RBAA1 | Apolipoprotein B/A1 ratio | 1874-7 |
Forms
If not ordering electronically, complete, print, and send a Cardiovascular Test Request Form (T724) with the specimen.