Sign in →

Test ID: A2M Alpha-2-Macroglobulin, Serum

Reporting Name

Alpha-2-Macroglobulin, S

Useful For

Evaluation of patients with nephrotic syndrome and pancreatitis

Specimen Type


Specimen Required


Preferred: Red top

Acceptable: Serum gel

Specimen Volume: 1 mL

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) and Time(s) Performed

Monday through Friday; 3 p.m.

Test Classification

This test has been cleared, approved or is exempt by the U.S. 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


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 other lower molecular weight proteins are lost and 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.


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;147:164-170

2. Haines AP, Howarth D, North WR, et al: Haemostatic variables and the outcome of myocardial infarction. Thromb Haemost. 1983;50:800-803

3. Hofmann W, Schmidt D, Guder WG, Edel HH: Differentiation of hematuria by quantitative determination of urinary marker proteins. Klin Wochenschr. 1991;69:68-75

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. La RIC Clin Lab. 1994;14:575-579

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. Rafai N, Horvath AR, Wittwer CT, eds: Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Elsevier; 2018

Analytic Time

Same day/1 day

Method Name



If not ordering electronically, complete, print, and send a Gastroenterology and Hepatology Client Test Request (T728) with the specimen.

Mayo Clinic Laboratories | Gastroenterology Catalog Additional Information: