Test Overview
Test Usage

Detection of naturally occurring IgM antibodies (anti-A and anti-B). May assist in the diagnosis of immune deficiency diseases.

Reference Range *

Interpretive report provided.

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

Test Limitations

Infants under twelve months of age frequently have low levels of isohemagglutinins; infants under three months of age may have maternal antibody present. Group AB patients will not have anti-A or anti-B; in these cases screening tests are done for IgM cold autoantibodies.

Test Details
Days Set Up
Monday - Friday, 8:00am - 4:00pm
Analytic Time

1 - 72 hours

Soft Order Code
MiChart Code
Isopropanol Level
  • ISO
  • Isohemagglutinin Screen
Blood Bank
Blood Bank
Specimen Requirements
Collection Instructions

Collect specimen in a pink top tube. Refrigerate and send intact specimen. Specimens are unacceptable if collected in serum separator tube, contaminated, or grossly hemolyzed. Specimens sent for Blood Bank testing cannot be split for use by other laboratories.

Alternate Specimen
IN-HOUSE: Lavender top tube (intact specimen) may be substituted for Pink top. All other specimen types are unacceptable. MLABS: Pink top tube (intact specimen) is preferred; the following are acceptable: lavender top (glass or plastic), red top (glass only), plasma aliquot from pink or lavender top, serum aliquot from red top. Plastic red top tubes will be rejected without exception. [9/03; rev 4/04]
This test is unreliable in patients under three months of age because maternal antibodies may be present.
Normal Volume
6 mL whole blood
Minimum Volume
2 mL whole blood
Storage Temperature
Additional Information

Sugar-sugar linkages that confer antigen activity (A,B,H) to the red cell membrane can also occur in biological materials, such as bacteria, viruses, food-stuffs, etc. Anyone with an intact immunological system can react to these naturally-occurring stimuli, resulting in elevated anti-A and/or anti-B titers. Titers may be decreased in congenital agammaglobulinemia and hypogammaglobulinemia. Titration of anti-A/B may be beneficial in the diagnosis of some parasitic infections; indicate this on the requisition.

CPT Code
Fee Code