Unlike acute hemolysis, delayed hemolysis may be insidious and develop over days to weeks. Likewise severity may vary from asymptomatic but only laboratory-detectable (i.e. delayed serologic reaction) to life-threatening only a few days after transfusion (e.g. an amnestic response to anti-Jka that was undetectable in the compatibility testing several days previously).
Remember that the most severe reactions may occur with weak or negative reactions!!
- In the first encounter of each patient with a positive direct antiglobulin test (DAT), the workup must include an acid-elution.
- Perform a DAT on patients with dropping hemoglobin levels not attributable to trauma, i.e. an anatomic defect.
- Obtain the full clinical history, medication history, and transfusion history (including at outside institutions)
- Check previous transfusion history.
- Send the DAT results (poly, IgG, C3d) and acid-elution to the Head, Transfusion Medicine or the Transfusion Medicine Physician covering the service.
- If the polyspecific DAT is positive, but only the monospecific C3 is non-negative, check with the Transfusion Medicine physician whether to perform the elution.
- He will write an interpretative report/comment appended to the DAT results in Hematos IIG.
- It is the decision of the Transfusion Medicine Physician preparing the report to decide if the clinician needs to be contacted.
- Standards for Blood Banks and Transfusion Services, Current Edition, AABB, Bethesda, MD, USA
- Guidelines to the Preparation, Use, and Quality Assurance of Blood Components, European Committee (Partial Agreement) on Blood Transfusion (CD-P-TS), Current Edition