(4) A washed RBC suspension may be prepared. Red blood cells
suspended in serum should not be used if the serum contains autoagglutinins, cold
agglutinins, or abnormal proteins that cause rouleaux.
b. Preliminary Testing. The following are imperative before crossmatching.
A review of blood bank records for results of previous testing.
(3) Rh typing and RhO(D) and control. Special care must be taken in testing
the recipient who may have received transfusions of an ABO group or Rh type different
from his own, since transfused cells may give misleading results.
(4) The screening of recipient sample for unexpected antibodies. This may
be performed at the same time as the crossmatch. Identify the antibody if the screen is
1-45. SELECTION OF BLOOD
(1) The blood selected for crossmatch should be of the same ABO group
and Rh type specific as that of the recipient when whole blood is being transfused;
however, there are instances when it is acceptable, or even advisable, to transfuse
RBCs of a different ABO group, provided that they are compatible. For example:
(a) When group-specific and type-specific blood is unavailable, as in
transfusing group A blood to an AB recipient.
For ABO and/or Rh hemolytic disease.
(2) It is not necessary to be concerned with subgroups of A, unless the
patient has a clinically significant anti-A1 or anti-'Hl'(O). Anti-'Hl'is also referred to by
different authors as anti-0, anti-IH, and anti-HO. Those examples of anti-O('Hl'), that are
not inhibited by H substance, are occasionally active at temperatures above 30C, and
have been known to cause rapid destruction of transfused incompatible RBCs. These
patients should receive A1 blood. Anti-A1, which is active "in vitro" at 30C higher, has
been shown to be capable of extensive red cell destruction. Therefore, these patients
should receive A2 blood.
(3) Matching of the Rh-Hr antigens other than RhO(D) is not recommended,
unless the patient has a known Rh-Hr antibody, in which case, blood lacking the
corresponding antigen must be selected, but it is not necessary to type donor blood for