b. Label all tubes, slides, and so forth, completely enough that there can be no
confusion about the identity of the unknown sample or the reagents in use.
c. Calibrate each centrifuge for the optimal time and speed needed for each
type of procedure. Record these data on the centrifuge and follow the instructions for
d. Record results immediately after observation.
e. Report interpretation, where appropriate, separately from recorded results.
f. Record the identity of the person performing each test.
2-12. ROUTINE TESTING FOR ABO
a. Background. Antibodies of the ABO system cause agglutination of saline-
suspended cells at room temperature or below. A high-protein medium does not
interfere with agglutination, but does not enhance it. Heating to 37C weakens the
reaction. Reagent antibodies agglutinate most cell samples when tested on a slide or
tile, without centrifugation to enhance the end point. For this reason, cell-testing can be
done either on a slide or in test tubes. Natively occurring antibodies may or may not be
strong enough to agglutinate cells without centrifugation; therefore, testing serum or
plasma for the presence of anti-A or anti-B is more reliably done in test tubes than on a
slide or tile.
b. Cell-Testing in Tubes. Each manufacturer has detailed instructions for its
own antiserums. Consult the local SOP for details. The following instructions are listed
in the current Technical Manual 8-227-2, Method 2.2.
Place one drop of anti-A into a clean, labeled tube.
Place one drop of anti-B into a second clean, labeled tube.
Place one drop of anti-A, B into a third tube.
Add to each tube one drop of a 2-5 tested.
Mix contents gently and centrifuge approximately 900-1000 g.
Gently re-suspend the RBC buttons and examine for agglutination.
Record test results.