combinations of reactions shown in the table 7-1
The most important Rh factor is factor D.
Approximately 85 percent of the population is
D positive (also called Rh positive), and
15 percent is D negative (also called Rh negative).
Aggiutinin for Rh + does not normally occur
in the blood. Consequently, Rh + corpuscles do
not produce reactions in first transfusions.
However, the agglutinogen, when present in large
amounts in the blood of recipients, may produce
reactions upon transfusion with Rh + corpuscles.
Consequently, it is mandatory to select compatible
donors whose corpuscles are Rh for transfusion
of Rh individuals. This is especially important
in those who have had previous transfusions
(especially with Rh + corpuscles).
TECHNIQUE FOR BLOOD
GROUPING AND TYPING
Determination of the A and B agglutinogen
is called grouping, while determination of the Rh
agglutination is called typing (fig 7-1.) Color-
coded Anti-A (blue), and anti-B (yellow), are
available through the Navy Supply System.
Blood grouping for the A-B-O system is
performed at room temperature. A blood
specimen is drawn and allowed to clot. The
erythrocytes are resuspended in the serum by
mechanical agitation, and single drops are placed
on a clean glass slide by a dropper. Colored
specific sera are added, and each drop of
blood and antiserum are individually mixed with
a clean applicator stick. The preparation is
Table 7-1.-Agglutination Reactions of the Red Cells of
the Four Blood Groups
Denotes absence of agglutination
+ Denotes presence of agglutination
observed for agglutination. If agglutination takes
place, the red cells gather in clumps. If there is
no agglutination, the red cells will be evenly
distributed over the field (see fig. 7-1).
The rouleaux formation is another phenom-
enon that causes trouble in blood typing. It
is caused by sera with high globulin content
and appears as red cells stacked up like a
pile of coins.
Rouleaux formation can
easily be confused with true agglutination.
CAUTION: Droppers must be used only in
their respective sera and cell suspensions to
prevent cross-contamination. Applicator sticks
used for mixing anti-A and the cell suspension
must not be used for mixing anti-B and the cell
suspension, and vice versa.
RESPONSIBILITIES IN THE
As a hospital corpsman, you need to know
how to perform the tests discussed in this chapter,
especially when you are on duty independent of a
medical officer. Although you are not expected
to diagnose or treat a patient based on the test
findings, you must be able to convey a clear
clinical picture to your supporting medical officer
to effect prompt, efficient, and professional
It is very important that the patient, as well
as the specimens received, be promptly and
properly identified to prevent errors and to
minimize future embarrassment and medical
Another important facet of clinical laboratory
is the proper use of laboratory forms. Use
separate forms for each patient and each type of
test. The forms must be filled out completely,
accurately, and legibly to ensure expeditious
disposition of completed reports. In addition, they
must be properly filed and recorded.
In the laboratory you constantly will be
dealing with the numerous laboratory forms
associated with the tests being performed. These
forms when used properly will minimize con-
fusion and reduce chances for errors. For a
complete listing of these forms and their purposes,
refer to MANMED, chapter 23.
ETHICS IN THE LABORATORY
You are expected to treat all laboratory tests
and their results as a confidential matter.