Blood Bank Tests & Interpretation
Common Blood Bank Tests
| Common Tests | Description | Turnaround Time | Expiration of the Sample |
|---|---|---|---|
| Type & Screen (T & S) | Type determines Blood Type (ABO) & Rh Type (+/-)Screens for unexpected red cell antibodiesIf an antibody is present, it is most often because of a previous transfusion or pregnancy | 45 min for STAT 120 min for routine | Expires at midnight of the third day after blood draw |
| Type & Crossmatch (T & XM) | Type is the same as a Type & Screen testing Crossmatch determines blood compatibility. The patient’s serum is combined with donor red cells. | 45 min for STAT if compatible blood is found | Expires at midnight of the third day after blood draw |
| Direct Antiglobulin Test(DAT or Coombs Test) | Positive test suggests antibody and/or complement on the red cells If the DAT is positive, rule out hemolysis if clinically indicated | 45 min for STAT 120 min for routine |
Interpretation of a positive Direct Antiglobulin Test
(DAT or Coombs Test)
The positive Direct Coombs test may be related to an underlying warm autoimmune antibody, alloantibody to a RBC antigen, drug-related or a non-specific finding. Rule out hemolysis (e.g. hemoglobin and hematocrit, reticulocyte count, LDH, bilirubin, haptoglobin, and complete urinalysis including microscopic) if clinically indicated. If hemolysis is suspected, please notify a Blood Bank Physician and obtain a Hematology consult.
Uncommon Blood Bank Tests
| Description | |
|---|---|
| Corrected Count Increment | Simple calculation used to screen for immune causes of platelet refractorinessPerform
a CBC 15 to 60 min after transfusing a single donor platelet (SDP) CCI < 7500/uL on 2 consecutive occasions highly suggests immune cause of platelet
refractoriness, if other etiologies (e.g. sepsis, hypersplenism, medications, bleeding)
can be excluded. |
| Antiplatelet Antibody Screen |
Must perform a Corrected Count Increment (CCI) first to screen for platelet refractoriness before ordering this send out testThis test used to confirm immune causes of platelet refractoriness (either HLA or anti-platelet antibodies) so a HLA matched or crossmatched platelet can be ordered. Turnaround Time: Send to New York Blood Center through the Blood Bank (at least 1 day) |