- Transaction Code: 3118-00 (to test single antigen, 1 or 2 tests)
- Transaction Code: 3117-00 (Rh phenotype and antigen typing ≥3 but <7 antigens tested)
- Transaction Code: 3136-00 (extended phenotype ≥7 antigens tested)
These tests are ordered for patient samples only. Donor or unit antigen screening information can be found under “Provision of Antigen Negative RBC Units” or “Provision of Crossmatch Compatible RBC Units”.
Antigen typing is performed using licensed commercial antisera to detect the presence or absence of individual blood group antigens (other than A, B or D).
Most typically done when a patient’s ABO and Rh type is needed. Unless the patient has known antibodies to other Rh antigens, the D type alone is sufficient for pre-transfusion testing.
When confirming or excluding HDN, it is often useful to order a single antigen typing to determine if a father carries the antigen corresponding to a maternal antibody. Single antigen phenotyping can also be ordered in other scenarios where the red cell antigen to be typed is known.
The Rh phenotype consists of typing for D, C, c, E, and e, if indicated. This is often useful for prenatal patients as the Rh system is the system most often involved in HDN.
Any patient that produces an unexpected antibody to one or more red cell antigens (such as K, k, Fya, Fyb, Jka, Jkb, S, s) will need an extended phenotype of all the common antigens to confirm or exclude antibody specificity. Patients who may require long-term transfusion therapy (ie. sickle cell anemia or WAIHA) often have extended phenotypes done to help identify the safest product for transfusion. When an antibody workup is done, an extended phenotype is part of the identification process.
- Sample Required: 7 ml EDTA (pre-transfusion preferred)
- Normal Test Values: Not applicable
- Analytic Time: 24 hours if weekday; 48 hours if weekend
- Days Test is Set Up: Monday through Sunday