Apolipoprotein Assessment

CPT: 82172(x2)
Print Share

Synonyms

  • Alpha and Beta Apolipoproteins

Test Includes

Apolipoprotein A-1; apolipoprotein B; apolipoprotein B:apolipoprotein A-1 ratio


Special Instructions

State patient's sex on the test request form.


Expected Turnaround Time

1 - 2 days


Related Documents

For more information, please view the literature below.

Spanning the Continuum of Cardiovascular Care


Specimen Requirements


Specimen

Serum (preferred) or plasma


Volume

4 mL


Container

Red-top tube, gel-barrier tube, green-top (heparin) tube, or lavender-top (EDTA) tube


Collection

Separate serum or plasma from cells within 45 minutes. Transfer specimen to a plastic transport tube.


Storage Instructions

Maintain specimen at room temperature.


Stability Requirements

Temperature

Period

Room temperature

14 days

Refrigerated

14 days

Frozen

14 days

Freeze/thaw cycles

Stable x3


Patient Preparation

Patient must be fasting 12 to 14 hours.


Causes for Rejection

Specimen from nonfasting patient


Test Details


Use

Studies have shown that the ratio of apolipoprotein A-1:apolipoprotein B may correlate better with increased risk of coronary artery disease (CAD) than total cholesterol, and LDL:HDL ratio.


Methodology

Immunologic


Reference Interval

See tables.

Apolipoprotein A-1

Male (mg/dL)

0 to 14 d

62−91

15 d to 11 m

53−175

1 to 5 y

80−164

6 to 12 y

107−175

>12 y

101−178

Female (mg/dL)

0 to 14 d

71−97

15 d to 11 m

53−175

1 to 5 y

80−164

6 to 80 y

116−209

>80 y

114−214

Apolipoprotein B1

Age

Male (mg/dL)

Female (mg/dL)

0 to 14 d

9−67

9−67

15 d to 11 m

19−123

19−123

1 to 5 y

41−93

41−93

>5 y

52−135

54−133

Apolipoprotein B:A-1 Ratio

Male

Female

Average risk

0.7

0.6

2x average risk

0.9

0.9

3x average risk

1.0

1.0


Additional Information

In 1971, Alaupovic suggested that apolipoproteins should be measured when assessing the relation of lipids and lipoproteins to CHD.2 Many patients with CHD were found to have normal serum and cholesterol levels. It was postulated that the chemical composition of the lipoproteins was more important for understanding the process of CHD than their blood levels. Subsequent studies have demonstrated that apolipoproteins are better discriminators than lipids and lipoproteins in patients with CHD and their relatives.

A number of studies have shown that apo A-1 and apo B correlate better with evidence of CHD than do lipoprotein measurements alone. In an investigation of first-degree relatives of patients with CHD, serum apo A-1 levels were significantly lower and apo B levels were significantly higher than those of healthy controls. Apo B was a better discriminator between male relatives, and apo A-1 was a better discriminator between female relatives and CHD patients. Furthermore, the percentage of correctly classified subjects increased by 12% when apo A-1 and apo B measurements were added as variables.

Avogaro et al found that serum apo A-1 and apo B levels, as well as various ratios using apolipoprotein measurements, were the variables that best discriminated male myocardial infarction survivors from age- and sex-matched controls.3

In 1983, Maciejko et al compared apo A-1 and HDL cholesterol measurements for their ability to identify male patients with angiographically assessed CHD.4 Analysis of their results indicated that apo A-1 alone misclassified 12.9% of the individuals compared to a misclassification error of 21.3% for HDL cholesterol alone. When apo A-1 and HDL cholesterol were used in combination, a misclassification error of 10.6% resulted. More recent studies have drawn similar conclusions.

When apo A-1, apo B, lipids, and lipoprotein cholesterol were measured in school-aged children (mean age of 10 years), apo A-1 and apo B levels were associated with a history of myocardial infarction in their parents. In striking contrast, the levels of serum lipids and lipoprotein-cholesterol values in these children were not related to myocardial infarction in either parent. Although no definite relationship between childhood apolipoprotein levels and adult CHD can be drawn, the results indicate that apolipoprotein measurements are more related to clinical disease than are conventional lipid measurements.5

Although the relationship of triglyceride measurements and CHD remains controversial, apolipoprotein measurements may be of benefit in identifying patients with hypertriglyceridemia who are at risk for CHD. Maciejko has suggested that apo B levels are helpful in differentiating primary causes of hypertriglyceridemia, provided that secondary causes (diabetes, alcohol ingestion, uremia, acromegaly, emotional stress or stress from acute illness, and certain drugs such as estrogen or beta blockers) have been ruled out. In familial endogenous hypertriglyceridemia, the apo B concentrations will be low while the patient with hypertriglyceridemia from familial combined hyperlipidemia will have a high apo B level.

Apolipoprotein measurements are also useful in the differentiation of familial hyper- or hypolipidemias. As mentioned, apo B may be used to differentiate familial combined hyperlipidemia from familial hypertriglyceridemia. Apo B measurements will also provide laboratory evidence of hyperapobetalipoproteinemia with excess apo B, whereas apo B deficiency states are found in abetalipoproteinemia, hypobetalipoproteinemia, familial hypobetalipoproteinemia with chylomicronemia, and abetalipoproteinemia with normotriglyceridemia. Apo A-1 deficiency states include Tangier disease, hypoalphalipoproteinemia, and HDL deficiency.

These studies indicated that apolipoprotein measurements can provide clarification in a variety of clinical states involving dyslipidemias. The Maciejko, Kottke, and Naito studies have concluded that apolipoprotein concentrations have greater discrimination in classifying patients who have or are predisposed to CHD and are more stable parameters than are lipids and lipoproteins.6 Lipids and lipoproteins are dynamic molecules whose concentration and composition are continually changing due to normal biologic variation, whereas apo A-1 and apo B levels are less affected, with change reflecting disease rather than biologic variability. In summary, apo A-1 and apo B measurements may be useful in the presence of the following conditions:

• Borderline elevations of cholesterol

• High cholesterol:HDL ratio with normal cholesterol

• Borderline elevations of LDL

• Normolipidemic children with a positive family history

• Normolipidemic adults with a positive family history

• Primary dyslipoproteinemias


Footnotes

1. Contois JH, McConnell JP, Sethi AA, et al. Apolipoprotein B and cardiovascular disease risk: Position statement from the AACC Lipoproteins and Vascular Diseases Division Working Group on Best Practices. Clin Chem. 2009; 55(3):407-419. 19168552
2. Alaupovic P. Apolipoproteins and lipoproteins. Atherosclerosis. 1971; 13(2):141-146. 5560875
3. Avogaro P, Bon GB, Cazzolato G, et al. Relationship between apolipoproteins and chemical components of lipoproteins in survivors of myocardial infarction. Atherosclerosis. 1980; 37(1):69-76. 7426089
4. Maciejko JJ, Holmes DR, Kottke BA, et al. Apolipoprotein A-1 as a marker of angiographically assessed coronary-artery disease. N Engl J Med. 1983; 309(7):385-389. 6410239
5. Kottke BA, Zinsmeister AR, Holmes DR Jr, et al. Apolipoproteins and coronary artery disease. Mayo Clin Proc. 1986; 61(5):313-320. 3702492
6. Naito HK. The association of serum lipids, lipoproteins, and apolipoproteins with coronary artery disease assessed by coronary arteriography. Ann N Y Acad Sci. 1985; 454:230-238. 3865610

LOINC® Map

Order Code Order Code Name Order Loinc Result Code Result Code Name UofM Result LOINC
216010 Apo A1 + B + Ratio 55724-9 016873 Apolipoprotein A-1 mg/dL 1869-7
216010 Apo A1 + B + Ratio 55724-9 167015 Apolipoprotein B mg/dL 1884-6
216010 Apo A1 + B + Ratio 55724-9 135038 Apolipo. B/A-1 Ratio ratio 1874-7

For Providers

Please login to order a test.

 

© 2019  Laboratory Corporation of America® Holdings and Lexi-Comp Inc. All Rights Reserved.

CPT Statement/Profile Statement

The LOINC® codes are copyright © 1994-2018, Regenstrief Institute, Inc. and the Logical Observation Identifiers Names and Codes (LOINC) Committee. Permission is granted in perpetuity, without payment of license fees or royalties, to use, copy, or distribute the LOINC® codes for any commercial or non-commercial purpose, subject to the terms under the license agreement found at https://loinc.org/license/. Additional information regarding LOINC® codes can be found at LOINC.org, including the LOINC Manual, which can be downloaded at LOINC.org/downloads/files/LOINCManual.pdf