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HelpTest Code A2M Alpha-2-Macroglobulin, Serum
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Reporting Name
Alpha-2-Macroglobulin, SSpecimen 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 a plastic vial
Reject Due To
| Gross hemolysis | OK |
| Gross lipemia | Reject |
| Gross icterus | OK |
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Refrigerated (preferred) | 21 days |
| Frozen | 28 days | |
| Ambient | 72 hours |
Specimen Minimum Volume
0.5 mL
Day(s) Performed
Monday through Friday
Specimen Retention Time
14 daysReport Available
1 to 3 daysReference Values
≤18 years: 178-495 mg/dL
>18 years: 100-280 mg/dL
Useful For
Evaluating patients with nephrotic syndrome and pancreatitis
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 |
Method Description
In this method, the light scattered onto the antigen-antibody complexes is measured. The intensity of the measured scattered light is proportional to the amount of antigen-antibody complexes in the sample under certain conditions. If the antibody volume is kept constant, the signal behaves proportionally to the antigen volume.
A reference curve is generated by a standard with a known antigen content on which the scattered light signals of the samples can be evaluated and calculated as an antigen concentration. Antigen-antibody complexes are formed when a sample containing antigen and the corresponding antiserum are put into a cuvette. A light beam is generated with a light-emitting diode, which is transmitted through the cuvette. The light is scattered onto the immuno-complexes that are present. Antigen and antibody are mixed in the initial measurement, but no complex is formed yet. An antigen-antibody complex is formed in the final measurement.
The result is calculated by subtracting the value of the final measurement from the initial measurement. The distribution of intensity of the scattered light depends on the ratio of the particle size of the antigen-antibody complexes to the radiated wavelength.(Instruction manual: Siemens Nephelometer II. Siemens, Inc; Version 2.4, 07/2019)
Forms
If not ordering electronically, complete, print, and send a Gastroenterology and Hepatology Test Request (T728) with the specimen.