Collecting a second sample to verify the results of current ABO testing on patients who do not have a historical blood type for comparison on file

A colleague reports that at her hospital they collect a second sample to verify the results of current ABO testing on patients who do not have a historical blood type for comparison on file. Lately a new modification to the policy has been requested. There are some surgical patients who come in ahead of time for whom verification of their ABO is desirable before surgery. What they have done in the past is that when a patient present for their surgical procedure, they obtain the second sample before the patient goes to surgery. In a couple of instances the patient was transported to the surgical holding room before the second specimen was drawn; the phlebotomist tried to obtain a second sample before the patient was taken into surgery, and the physician was very upset. What is being proposed is to collect two specimens when the patient presents for pre-surgical lab work in the Preop center; it has been decided that when the patient is drawn the first time a second phlebotomist must draw the second sample at a different time for certain patients that are scheduled for major surgery before the patient leaves the Preop center; it will not be required that they find out from the lab if the second sample is needed, before collecting a second sample. There is another scenario that the inquiring colleague would like to discuss; Per policy if there is an emergency situation it is not necessary to collect a sample for ABO verification; if the patient needs blood urgently they will offer group O red cells; however, in several occasions they have received and order from surgery for a type and antibody screen on a patient that was scheduled for surgery; the anesthesiologist has collected two specimens and he has indicated that they are drawn two to five minutes apart. In two of the instances they did not need a second blood sample. The inquiring colleague would like some feedback on what other facilities have experienced and to know if they have scenarios similar to the ones described above.

The Editors suggest review of the previous e-Network Forum discussions:

• Should pre-transfusion ABO/Rh testing be performed twice, and if so, on different samples or by different personnel?
• A network dialogue on the question of using a second blood sample to verify a patients ABO/Rh type

The following comments have been submitted.

ADDENDA May 14, 2009

1. A transfusion medicine physician with many years experience at an academic institution in Virginia reports that at his institution, they do not routinely collect two separate specimens for ABO grouping. Rather, he is of the opinion that regardless of what an institution's procedures and policies are with respect to ABO grouping, the most important part of such a process is the assurance of proper identification. If the institution can get the identification of patient, specimen, and component completely correct, then it seems to be of little consequence how many ABO groupings are performed. He also thinks that the transfusion service should control the policies related to proper identification.

2. A transfusion medicine physician in Denmark reports that in his practice if a patient who requires transfusion has a single ABO/Rh recorded in their laboratory information system (LIS), a second sample is drawn for confirmation of blood group (and antibody screen). If the ABO/Rh results match and the antibody screen is negative, blood carrying the patient's ABO RhD type is issued (electronic Xmatch) - In case of a positive antibody screen, the antibody is identified and compatible blood is issued (so called "wet Xmatch"). If there is no recorded historical type, an initial sample is drawn for ABO RhD type (and antibody screen) - a second sample is obtained at a different time and preferably by a different phlebotomist. The ABO RhD type is compared with results from the first sample (electronically). If results match and the antibody screen is negative, blood (patient type) is issued by e-Xmatch for up to 4 days, when a new sample is required. In critical situations with urgent need for transfusion, uncrossmatched group 0 Rh Negative RBC units are transfused. As soon as possible the laboratory switches to ABO/Rh identical (or compatible) RBC units, once the results from a second sample are known and match the first sample. Regardless of the amount of group 0 RBC units given, they switch to ABO/Rh identical (or compatible) RBC units as soon as possible. They use buffy coat depleted SAGM blood from a Bottom/Top system and see no cases of hemolysis when reverting to the patient´s own ABO group - even after massive transfusion with group 0 RBC units.

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

W. Tait Stevens, MD
CBBS e-Network Forum Assistant Editor & Moderator