(d) Hemolysis. Antibodies most often hemolyzing saline-suspended
cells are anti Lea and Kidd antibodies.
(e) Enzymes. Anti-Fya, -FYb, -M, -N, -S may not be detected when
enzymes are used. Rh antibody reactions are enhanced by the enzyme procedures in
common use. In fact, these procedures were developed originally to detect Rh
antibodies. Conversion of the test to AGT will aid in identifying weak Kidd antibodies.
In addition to the antibodies listed in d, anti-P1 may also be hemolytic in an enzyme
b. All panel cells are equally positive; autocontrol negative.
(1) An antibody against a high-frequency antigen or a mixture of antibodies
may be present.
Testing against specially selected cells is necessary for identification.
(a) At RT. 18C or 4C. Antibodies that fit this pattern include anti-Sda,
anti-l in an l-negative person, anti-H or -HI in individuals of group A1, A1B, or
(infrequently) B. Serums from Bombay or p people also react in this way.
(b) At 37C. Antibodies against high-incidence antigens that may react
are anti~Lu and Vel.
(c) After AGT. Almost all antibodies for high-incidence antigens will
react by the antiglobulin test. The more common are: anti-k, Kpb, -U, -Yta, -Vel, -Lan, -
(d) Hemolysis. The antibodies for high-incidence antigens that cause
hemolysis "In vitro" are anti-Vel and -PP1Pk.
c. All panel cells are autocontrol positive at RT; stronger at 4C: weaker at 37C;
antiglobulin phase variable, usually weak. A cold antibody, usually anti-I, with
autologous activity may be present. Rouleaux formation and fatty-acid-dependent
antibodies may give a comparable picture. Since cold autoantibodies may mask the
simultaneous presence of alloantibodies, the serum should be autoabsorbed, and the
antibody-screening and identification procedure repeated on the absorbed serum.
d. Cells on panel are negative or variably positive; autocontrol positive in
antiglobulin phase. The subject's cells may have a positive DAT at the same time that
an alloantibody is present in the serum. In autoimmune hemolytic anemia, all
antibodies may be bound to the cell so that none will be detectable in the serum (see
Lesson 2, Section I).