Lab Test

Red Blood Cell Antibody Screen

Indirect Coombs, Indirect Antiglobulin Test, AB Screen, RBC Antibody Screen

Test Codes



Specimens used for transfusion purposes must be drawn within 3 days of intended transfusion. Day of collection is Day 0. Tubes drawn for cryoprecipitate, fresh frozen plasma (FFP), or platelet transfusions may be more than 3 days old, but must be obtained during the current admission/visit.

Specimen Collection Criteria

Collect: One Pink-top EDTA tube, properly labeled. (Minimum Volume: 5.0 mL)
Also acceptable: (For Nursery Patients) One Pink-top EDTA Microtainer®, properly labeled. (Minimum Volume: 0.5 mL)

It is extremely important that blood samples are accurately labeled. Inpatient labels must include the following information:

  1. Patient's Name: Complete name, last name first. If the patient uses a first initial followed by a middle name, both must appear in proper order on the label.
  2. Wrist Band Number:  Include the prefix letters, 4 numbers, and a suffix letter (example: BR1234T). Specimens lacking this complete information cannot be used for blood transfusion purposes.
  3. Hospital Identification Number: The seven-digit medical record number must be included on the label.
  4. Date and Time Collected
  5. Identification of Collector: Employee ID number must be on the sample tube or documented in the computer system.

For Beaumont Reference Laboratory (Outreach) patients, please refer to the Laboratory Bulletin on Laboratory Specimens: How to Label Correctly

Physician Office/Draw Specimen Preparation

Maintain specimen at room temperature (20-26°C or 68-78.8°F) or refrigerated (2-8°C or 36-46°F) prior to transport.

Preparation for Courier Transport

Transport: Whole blood at room temperature (20-25°C or 68-77°F) or refrigerated (2-8°C or 36-46°F).

Rejection Criteria

  • Improperly labeled specimens.
  • Specimens with inadequate volume.
  • Specimens collected in SST tubes.
  • Specimens contaminated with IV fluids.
  • Hemolyzed samples will be tested only in emergency situations. 


Specimen Stability for Testing:

Room Temperature (20-26°C or 68-78.8°F): 24 hours
Refrigerated (2-8°C or 36-46°F): 72 hours
Frozen (-20°C/-4°F or below): Unacceptable

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): Specimens are held for a minimum of 7 days.

*Once a sample arrives in Blood Bank, it cannot be shared with other laboratories.


Farmington Hills Transfusion Medicine Laboratory (Blood Bank)
Grosse Pointe Transfusion Medicine Laboratory (Blood Bank)
Royal Oak Transfusion Medicine Laboratory (Blood Bank)
Troy Transfusion Medicine Laboratory (Blood Bank)
Dearborn Transfusion Medicine Laboratory (Blood Bank)
Taylor Transfusion Medicine Laboratory (Blood Bank)
Trenton Transfusion Medicine Laboratory (Blood Ban)
Wayne Transfusion Medicine Laboratory (Blood Bank)


Sunday – Saturday, 24 hours a day.
Results available within 2 hours of receipt in the Blood Bank for routine inpatient requests and within 8 hours of receipt in the Blood Bank for outpatient specimens.

Reference Range


Test Methodology



  • Negative: No antibody detected.
  • Positive: Antibody detected. Follow-up antibody identification will be performed as indicated per policy. The antibodies should be identified in order to determine their potential for harm to the patient and to assess appropriate action to be taken in the future. Antibody identification is performed and billed at a separate additional charge if indicated.
  • False negative test results may occur if the serum being tested contains an antibody directed toward an antigen not represented on the reagent red blood cells being used for testing. False negative results may also be obtained if the antibody titer falls below detectable levels.
  • Note: Nursery antibody screen results are for transfusion purposes and may reflect either mother's or baby's antibody screen.

Clinical Utility

The antibody screen aids in the detection of allo-antibodies directed against red blood cell antigens. This test is used for pretransfusion testing, evaluation of transfusion reactions, to assess the potential for hemolytic disease of the newborn/fetus, and for the evaluation of hemolytic anemia.

CPT Codes



Last Updated


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This directory currently reflects information only for specimens collected and/or processed at the
Farmington Hills, Grosse Pointe, Royal Oak, and Troy campuses.