3 Plasma electrolyte concentration, within limits, which are
tolerable for infants.
(f) If the clinical situation is critical, slightly older blood may be used.
CPD blood is suitable for use in exchange transfusions, but some prefer heparinized
Compatibility testing for exchange transfusion.
(a) The compatibility tests should be performed using the mother's
serum and the donor's red cells. The mother's serum is the specimen of choice since
the offending antibody is present to a higher titer in her serum than in the infant's serum.
If the mother's blood cannot be obtained, the compatibility test is performed using an
eluate of the cord cells or, if time is critical, the baby's serum. It is important not to
cause needless delay by waiting for a maternal blood sample that may require some
time to obtain.
(b) In repeated exchange transfusion, subsequent units should be the
same blood group, and type as the first unit. After each exchange, a sample of blood
should be drawn from the infant and used in compatibility testing for future exchange
transfusion. In addition, it is advisable to use samples of maternal serum.
(c) A common problem is the presence in the maternal serum of
anti-Lewis, IH, I, or H, as previously described, in addition to the lgG antibody
responsible for the hemolytic disease. Such cold lgM antibodies may delay locating
completely compatible blood unless they are ignored. When present, donor units
incompatible with the maternal serum may be used for the exchange transfusion
provided they lack the antigen that corresponds to the maternal IgG antibody.
Alternatively, one may use maternal serum for the compatibility test after treatment with
two-mercaptoethanot or dithiothreitol.
(d) Compatibility tests after delivery are best performed using the cord
cell eluate, when this problem exists.
Exchange transfusion in patients with an antibody to a high-frequency
(a) Rarely, the mother's serum may contain an antibody to a high-
incidence factor and no compatible blood is available. Recognition and identification of
this problem during pregnancy will allow the blood bank time to work with the AABB
Rare Donor File to locate compatible donors and to test the siblings of the mother for
compatibility and suitability. If this problem is not recognized until after delivery and the
need for donor blood is urgent, three choices are open.
1 If available, test the mother's siblings for compatibiIity and