Policies on verification of typing of antigen-negative red cell units received from blood suppliers

A transfusion medicine technologist in California reports that from time to time her hospital orders RBC units from their blood supplier from donors that lack certain red cell antigens. These specially typed RBC units are ordered prophylactically for transfusion of non-alloimmunized patients with sickle cell anemia and thalassemia, or for patients who have already been alloimmunized. Upon receipt of these units, they 'serologically confirm' the antigen typing by performing the typing in their own lab. For example, if a donor unit is labeled as K, C and E negative, her lab would perform those typings for the sake of verification. She wants to know if other laboratories also 'verify' such antigen typings, or do they place full reliance on the blood supplier's typings.

The following responses have been received.

ADDENDA Sept. 23, 2004

1. The Blood Bank Manager at a hospital in Texas reports that they do NOT confirm antigen typings of donor RBCs (other than ABO and D) using individual antisera. Since their blood center is FDA-licensed and AABB certified, they feel comfortable in trusting the donor center's antigen typing results and consider a compatible AHG phase of the crossmatch to be a confirmation of the antigen typing. In addition, since her laboratory often does not have the necessary typing antisera, re-testing may not even be an option.

2. A Transfusion Service Supervisor at a hospital in Utah reports that this topic has been quite a discussion item within transfusion services of his hospital corporate network. The facilities within the corporate network vary from 500+ beds to <20 beds. The smaller, rural facilities are not able to re-type for the antigens simply because they do not stock the antisera to do so. Those transfusion service laboratories must accept the blood supplier's typing results. There are 4 or 5 "larger" facilities within the network that are somewhat split on the issue. His particular facility does not re-type the donor RBCs to verify antigen status, other than for ABO and D (when product is labeled Rh negative). He is unaware of any mistyped unit being received at a network hospital in over 2 years. Interesting, however, his facility has received donor RBC units that were typed for the wrong antigen, although the typing that was done was performed accurately; they asked for Jk(a) negative units but received Fy(a) negative units. Fortunately, the units were clearly labeled as to what antigens had been typed.

ADDENDA Sept. 28, 2004

3. A colleague at a hospital in a somewhat remote location reports that they DO retype antigen-negative red cell units that they receive from their blood suppliers. They perform this retyping only for the antigens for which they have typing sera available. She reports that they continue with this policy because about once a year they discover that their blood supplier has mistyped a unit. Because some of the patients for which they specially antigen-typed units no longer have a detectable alloantibody (especially anti-Jka), reliance on a crossmatch will not always detect the mistyping.

(Editor's Comment: Viewers should note the disagreement between this statement and that by the Texas colleague in #1 above.)

ADDENDA Sept. 29, 2004

4. A blood bank supervisor at an FDA-licensed, AABB accreditated institution in Texas reports that it is their policy to re-test 'antigen negative' units received from their blood provider. She reports that so far during calendar year 2004 they have already received 2 RBC units on two separate occasions which were typed as "negative" for a specific antigen, but upon re-typing by her facility the antigen typings in question were actually positive. This was reported to the blood supplier who confirmed the antigen positive status of the units by also doing re-typing. One of the typing mistakes was due to human error when the technologist typed the unit for the wrong antigen. The second error reportedly stemmed from using a weak-reacting typing reagent.

ADDENDA Sept. 30, 2004

5. A colleague at a blood center in the Midwestern USA reports that some of their client hospitals always re-type these antigen-negative units as a matter of policy, to confirm the donor center's typing results. However, this is not a universally applied policy. For example, one facility that consdered stopping such retyping collected data comparing the typing results reported by the collection center versus the results obtained by their own technologists. Finding no discordance in typing results between the two, they discontinued re-typing antigen-negative RBC units.

ADDENDA Oct. 3, 2004

6. A colleague in Texas reports that the policy at her hospital is to re-test antigen negative units received from the blood supplier. This practice paid off because on several occasions they discovered that the antigen typing of the RBC unit did not coincide with the results recorded on the unit by the blood supplier. When they encounter such discordance they return the unit to the blood supplier for confirmation. In more that one instance a mistyped unit was 'compatible' when it was crossmatched, because the patient's antibody was below the threshold of detection.

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