Test Overview
Test Methodology

Nephelometry

Test Usage

To evaluate humoral immunity, to diagnose and monitor the therapy of secretory B cell neoplasms (e.g., myeloma, Waldenstrom's macroglobulinemia). Newborn IgM levels are used as a screen to evaluate likelihood of in utero infections. Cord or neonatal serum may be screened for infections acquired in utero.

Reference Range *

Cord blood (age <1 mos): 6 - 25 mg/dL, age 1 mos: 20 - 80 mg/dL, age 2-5 mos: 25 - 95 mg/dL, age 6-11 mos: 35 - 140 mg/dL, age 1-7 yrs: 40 - 190 mg/dL, age 8-11 yrs: 50 - 240 mg/dL, age 12-150 yrs: 50 - 370 mg/dL.

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Test Limitations

If samples containing macroglobulins, cryoglobulins or cold agglutinins are handled at incorrect temperatures, falsely lowered values may result.

Test Details
Days Set Up
Monday - Friday
Analytic Time

8 hours

Soft Order Code
IGM
MiChart Code
IgM
Synonyms
  • IgM
  • Quantitative IgM
  • IMMUNOGLOBULIN M
Laboratory
Chemical Pathology
Section
Immunopathology
Specimen Requirements
Collection Instructions

Collect specimen in SST tube. Centrifuge, aliquot serum into a plastic vial and refrigerate.
Store at 2-8°C up to 8 days.
Samples may be frozen at -20°C or below for up to 3 months if they are frozen within 24 hours after collection.

Alternate Specimen
Red top
Yellow Top Tube
Normal Volume
0.5 mL serum
Minimum Volume
0.3 mL serum
Additional Information

IgM is commonly increased in viral infections, IgM monoclonal gammopathy, estrogen therapy, nephrotic syndrome and following several blood transfusions. IgM is a gamma globulin and the first type of antibody produced by the fetus. IgM does not cross the placenta due to its large size. It is the first form of antibody generated during the immune response, a 19S pentamer of (7S) subunits, usually at low levels at birth, and elevated (usually over 25 mg/dL) in the newborn in association with intrauterine infections such as rubella, syphilis, cytomegalovirus infection and others.

Billing
CPT Code
82784
Fee Code
21988
Resources