the requisition is generated by physician or other authorized healthcare professional
all paperwork/wristbands must have minimum of 2 independent identifiers
there is usually additional information like patient name and DOB
the test can be STAT, ASAP, or routine
ABO and Rh must be determined before transfusion except in emergency situations where there is no time -- give O +/- until the type and cross is done
The patient's location (ER, OR, etc) can imply an emergency; ER usually takes precedence
Ottenberg used minor and major crossmatching
Tubes
can collect a red top tube (no additive) or a lavender top (gel technology)
plasma is preferred because you don't get small clots forming which may be confused as aggregates, particularly in the gel technique
do not use tubes with clot activators or silicone coating
The sample
cannot be lipemic or hemolyzed
certain antibodies produce hemolysis (ABO, P, Lewis, Kidd...)
it should not be contaminated with any IV fluid -- always draw below an IV
it blood is drawn from a line, the first 5-10mL of blood should be discarded before filling tubes for blood banking
sample retention and record review
check for past adverse reactions to transfusions, special transfusion requirements, and unexpected antibodies in the file - if the patient had one, even it is no longer showing up, must give patient blood free from that antigen. Don't want to risk an anamnestic response
Pretransfusion testing
some facilities require manufacturers to supply selectogen cells taht are homozygous (double dose) for clinically significant antibodies
this is because some antibodies show dosage
dosage means that the antibodies react better when the antigen is homozygous, and they react weakly with antigens that are heterozygous on the RBCs
Group O was designated as the universal donor
It was discovered that patient antibodies to RBCs could be harmful
In 1939, the Rh factor was discovered, and it was found necessary to recognize incomplete IgG antibodies to Rh