A member recently asked: "How many sites repeat the antigen typing (e.g., K negative) for units they receive from their supplier?" Currently, the inquiring member’s institution is repeating the typing for antigens to which their lab has antisera, but for other antigens, the institution must take the blood supplier's word, as repeat the testing cannot be done.

To which the following replies were received:

1. We perform most of our antigen typing in-house, but we do repeat antigen typing for units we receive from our supplier for which we have antisera.

2. I work at a transfusion service for a 350-bed hospital, where 7200 RBC units are transfused annually. We repeat or confirm the antigen typing of units typed at the donor center. The reasoning behind this policy is as follows:

1. We at the transfusion service are the final "arbiters" and quality checkers of the suitability of units for transfusion. I think this is similar to confirming ABO and Rh on units.
2. Occasionally the donor center (especially on weekends) may ask if they can send a unit that is "historically" negative for an antigen in question - but not confirmed on the current donation. In my opinion, such a unit would REQUIRE (see Editor's Note) antigen typing at the transfusion service. Furthermore, performing antigen confirmations on all units eliminates making the decision on which units require confirmation and which don't.
3. Lastly, we sometimes (rarely) detect a mistake in antigen typing by the donor center.

Editor’s NOTE: I do not believe that there is an actual REQUIREMENT for the transfusion service to confirm antigen typing of donor units that have been performed by the donor center, other than to confirm ABO labeling of red cell products and Rh negative labeling of red cell products. However, it may be good practice to confirm the other antigen typings, as the discussant of this question suggests.

3. Every transfusion service that I have been involved with has had the policy to verify the antigens upon receipt of the unit, but only for those antigens against which the intended recipient has antibodies. i.e. would not verify all the antigens listed on the tag. If there is not commercial antisera available, then the supplier's typings would be relied upon and the units would be supplied as crossmatch compatible. It has been my experience that I have received several units that had been incorrectly tagged as to their antigen negative status. This would most certainly be a huge problem if your patient's antibodies are no longer demonstrable.

4. We recently received a unit from our blood supplier that was labeled K negative. Our repeat typing showed the unit to be K positive. Repeat testing by the blood supplier was K positive. I recommend repeating the antigen typing unless your blood supplier has a system to ensure human errors will be detected before the unit is released for distribution. As long as the recipient's antibody reacts in routine testing the crossmatch will detect a unit that has been mistyped. The problem is the recipient whose antibody is not currently detectable. If you don't have commercial reagent anti-sera consider collecting patient sera containing detectable antibodies.

5. The blood bankers at a prestigious medical center near Berkeley decided not to repeat antigen typing performed by their primary blood supplier since 1999 because of their excellent record of zero error rate. The medical center does retype historical antigen negative units.

6. Our facility antigen retypes all units except for the rare types that we do not have antisera for. We have found on the rare occasion a mistype by our reference facility, and it gives us confidence that we are providing the best selection for the patient.

7. We repeat the antigen testing and we have caught 3 errors. Rare I know, but we all are human.

8. A blood collection center wrote that their major hospital transfusion services repeat typing on units for which they have antisera. Their smaller transfusion services do not repeat these typings and some of these transfusion services allow their crossmatches to be done by the blood collection center, so that these crossmatches are tests of record.

ADDENDUM Oct 3, 2000

9. Our blood bank has been confirming antigen typing done by our blood center. The reasoning was historical - the antisera used for screening units were not licensed and our laboratory requirements were to used licensed reagents except for the very rare situations. We are in the process of changing to not confirming antigen-tested units that have been screened by licensed antisera. Patients with multiple antibodies can be extremely expensive just to obtain the units from our supplier and then to confirm it adds expense that just may not be indicated. I certainly will be interested in all the responses. We are also looking at the buck stops with the Hospital Transfusion Service quality - what would John Q Public's attorney have to say if we had an oversight?

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Ira A. Shulman, MD
CBBS e-Network Forum Editor & Moderator