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HelpTest ID: A2M Alpha-2-Macroglobulin, Serum
Reporting Name
Alpha-2-Macroglobulin, SUseful For
Evaluating patients with nephrotic syndrome and pancreatitis
Specimen Type
SerumSpecimen Required
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions: Centrifuge and aliquot serum into plastic vial
Specimen Minimum Volume
0.5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Refrigerated (preferred) | 21 days | |
| Frozen | 28 days | ||
| Ambient | 72 hours |
Reference Values
≤18 years: 178-495 mg/dL
>18 years: 100-280 mg/dL
Day(s) Performed
Monday through Friday
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
83883
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| A2M | Alpha-2-Macroglobulin, S | 1835-8 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| A2M | Alpha-2-Macroglobulin, S | 1835-8 |
Clinical Information
Alpha-2-macroglobulin is a protease inhibitor and is one of the largest plasma proteins. It transports hormones and enzymes, exhibits effector and inhibitor functions in the development of the lymphatic system, and inhibits components of the complement system and hemostasis system.
Increased levels of alpha-2-macroglobulin are found in nephrotic syndrome when lower molecular weight proteins are lost, but alpha-2-macroglobulin is retained because of its large size. In patients with liver cirrhosis and diabetes, the levels are found to be elevated.
Patients with acute pancreatitis exhibit low serum concentrations, which correlate with the severity of the disease. In hyperfibrinolytic states, after major surgery, in septicemia, and severe hepatic insufficiency, the measured levels of alpha-2-macroglobulin are often low. Acute myocardial infarction patients with low alpha-2-macroglobulin have been reported to have a significantly better prognosis with regard to the greater than a year survival time.
Interpretation
Values are elevated in the nephrotic syndrome in proportion to the severity of protein loss (lower molecular weight).
Values are low in proteolytic diseases such as pancreatitis.
Clinical Reference
1. McMahon MJ, Bowen M, Mayer AD, Cooper EH: Relation of alpha-2-macroglobulin and other antiproteases to the clinical features of acute pancreatitis. Am J Surg. 1984 Jan;147(1):164-170. doi: 10.1016/0002-9610(84)90052-7
2. Haines AP, Howarth D, North WR, et al: Haemostatic variables and the outcome of myocardial infarction. Thromb Haemost. 1983;50(4):800-803
3. Hofmann W, Schmidt D, Guder WG, Edel HH: Differentiation of hematuria by quantitative determination of urinary marker proteins. Klin Wochenschr. 1991 Jan 22;69(2):68-75. doi: 10.1007/BF01666819
4. Solerte SB, Adamo S, Viola C, et al: Acute-phase protein reactants pattern and alpha 2 macroglobulin in diabetes mellitus. Pathophysiological aspects in diabetic microangiopathy. RIC Clin Lab. 1984;14(3):575-579. doi: 10.1007/BF02904891
5. Silverman LM, Christenson RH, Grant GH: Basic chemistry of amino acids and proteins. In: Tietz, NW ed. Clinical Guide to Laboratory Tests. 2nd ed. WB Saunders Comp; 1990:380-381
6. Rifai N, Horvath AR, Wittwer CT, eds: Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Elsevier; 2018
Report Available
1 to 3 daysMethod Name
Nephelometry
Forms
If not ordering electronically, complete, print, and send a Gastroenterology and Hepatology Test Request (T728) with the specimen.
mml-gi-liver-autoimmune