Test Overview
Test Usage

To detect IgG immunoglobulin and/or complement adherence to red cells, as seen in immune hemolytic anemia or in a delayed hemolytic transfusion reaction. Positive tests will be further evaluated for bound and unbound antibody specificities associated with Cold Hemagglutinin Disease, Warm Autoimmune Hemolytic Anemia, and delayed reaction to transfusion. Positive tests will be further evaluated to determine the specific type(s) of protein adhering to the red cells and present in the serum (indirect test).

Reference Range *


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

Test Limitations

Use of red top tubes or serum separator tubes may cause false positive reactions.

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

1 - 72 hours

Soft Order Code
  • Coombs Antibody
  • Coombs Test
  • Coombs' Antibody
  • Coombs' Test
  • IgG DAT
  • C3 DAT
  • DAT Study
  • Direct Coombs`
Blood Bank
Blood Bank
Specimen Requirements
Collection Instructions

Collect specimens in two pink top tubes. Send intact specimens at room temperature. 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). Plastic red top tubes will be rejected without exception. [10/03; rev 4/04]
Normal Volume
7 mL whole blood
Minimum Volume
7 mL whole blood
Storage Temperature
Additional Information

If the DAT is positive at 1+ or less, additional antiglobulin testing and an antibody screen will be performed at an additional charge (for subsequent specimens on the same patient that are positive at 1+ or less, the antibody screen will not be performed). If the DAT is positive at 2+ or greater, monospecific testing and an eluate/absorption panel will be performed at an additional charge. If the antibody screen is positive, an RBC identification panel will be performed at an additional charge. Tests for drug directed antibodies performed following consultation. By ordering this test the clinician acknowledges that additional reflex testing will be performed and billed at a separate additional charge if indicated.

CPT Code
86880 x2
Fee Code
21256, 21257 x2
Reflex Fee Code
21257, 21253, 21267