(2) The results of HBsAg and HCV testing must be included on the label(s)
of all units of blood and blood components, along with a statement of the possible
presence of the agents(s) of viral hepatitis despite this testing being negative. Only in
dire emergency situations may blood be transfused before completion of the HBsAg and
HCV tests. If the test is subsequently found to be positive, the recipient's physician
must be notified. Since each unit of blood must be tested at the time of donation,
retesting for HBsAg and HCV are not considered necessary for blood from an "outside"
b. Special Notes.
(1) When RBCs are to be used for antibody stimulation, the HBsAg status of
the cell donor should be negative at the time of each donation; when possible, a donor
should be used whose blood is considered to carry a minimal risk of hepatitis.
(2) Do not routinely test intended transfusion recipients for HBsAg. HBsAg
testing of the patient should be performed only when directly related to his diagnosis or
(3) The presence of anti-HBs in donor blood is not associated with an
increased risk of type B hepatitis. Thus, testing for anti-HBs in donors is of little
practical value at the present time.
(4) All HBsAg and/or HCV positive blood should be retested and confirmed
as HBsAg-positive and/or HCV-positive since all test methods can give false positive
results (see figure 3-3).
(5) As with all areas of the laboratory, quality assurance is important in
HBsAg and HCV testing. Satisfactory participation in a proficiency test program should
be part of the quality assurance of HBsAg tests (the American Association of Blood
Banks and the College of American Pathologists sponsor such a program).
(6) All blood products and samples should be regarded as potentially
infectious, whether are not they are HBsAg-positive. Minute amounts of HBsAg and
associated hepatitis B virus may be undetectable in some serums by all current tests,
yet the blood may transmit hepatitis B after inoculation or transfusion. In addition, HCV
may be present and these are unrelated to HBsAg.
(7) The use of frozen RBCs (human) may diminish the risk of post-
transfusion hepatitis. This effect, if substantiated, may be a result of the extensive
washing of the thawed cells during de-glycerolization. The cost effectiveness of the
routine use of frozen cells is questionable, so they should be used only when there is a
clear-cut indication for their need.