Hematology and Blood Transfusion Science
Domain focus
Haematology and transfusion science questions cover CBC interpretation, anaemia classification, coagulation testing, ABO/Rh grouping, antibody screening, crossmatching and transfusion reaction investigation, with attention to Cambodia's hospital blood banks and the National Blood Transfusion Centre.
Core rules
- Verify patient identity and sample labelling at the bedside; a mislabelled pretransfusion sample is never acceptable.
- Perform ABO/Rh forward and reverse grouping; resolve discrepancies before issue.
- Crossmatch against the patient's current sample; use group-compatible, crossmatch-compatible red cells.
- Stop any transfusion immediately if fever, chills, dyspnoea, flank pain or dark urine occurs.
- Interpret CBC trends with the clinical picture: MCV classifies anaemia, reticulocyte count indicates marrow response.
Worked example
A patient develops fever, chills and dark urine 15 minutes into a red cell transfusion. The correct sequence is: stop the transfusion, keep the IV line open with saline, check identity and unit labels, repeat ABO/Rh and antibody screen, perform a direct antiglobulin test, examine plasma for haemolysis and send urine for haemoglobin. The likely diagnosis is an acute haemolytic reaction, most often from ABO incompatibility or clerical error.
Traps
- Accepting a verbally identified patient without wristband check.
- Reporting EDTA-induced platelet clumping as thrombocytopenia; examine the film.
- Confusing cold agglutinin artefact with true pancytopenia.
- Issuing blood before the antibody screen is complete.