Resulting antigen typing on the second unit of a double red cell collection from results obtained from first unit

[conwaysbb]

My staff has asked a question that has stumped me. :-) We have been getting both units of a double red cell collection. When you antigen type one unit of a double red cell collection can you use the results obtained for the other unit or do you have to repeat the testing on an integral sample from the second unit.

Part of me says that when we do donor testing on the donor specimen collected at the time of donation, we use these results to release both units of a double red cell collection.

Part of me says that even though they share the same unit number, they both should be tested separately using an integral segment obtained from each unit at time of testing.

I am leaning towards having each unit tested, as I would still require a x-match be performed from an integral segment from both units and I retype of both units.

What say you?

[Marilyn Plett]

My vote: If the donor specimen is good enough for HIV, it's good enough for antigens.

[Eagle Eye]

I have to say that I would test both units.....basically I want to test it from attached segment.

I would not take chance of releasing unit without testing.

[Deny Morlino]

There is always a possibility of labeling error (yes very slim, but still possible). Conservative says Ag type both.

[Liz]

Process each unit as a separate donation; just as you woud process an autologous unit as an allogeneic one. Always go towards the option that offers the most patient-safety.

[David Saikin]

I would type both units.

[skopti]

I would type both units

[John C. Staley]

My thoughts are to keep it simple. When you have a process and then try to define exceptions to that process it provides more opportunity for errors. It was the same concept we had with Autologous units. We were not required to do any infectious disease testing on them but it was easier and more consistant to treat all donor units the same than it was to try to keep track of the ones that did not need the testing.

While I certainly agree with the logic of not testing both bags of a double unit and I would lean towards all or nothing. If you are going to require the crossmatch for both bags then require everything otherwise you are leaving your staff open to confusion especially when pressed for time.

[David Saikin]

Thank you John . . .

[Marilyn Plett]

John makes an excellent point about making the process simple and consistent. However, I don't think that means that there is only one answer here. A donor center might have easy access to donor specimens. If you are computerized, how does your computer system record the results? To the donation or to bag 1 or bag 2, depending on which is tested? Antigen testing by molecular methods would use the donor specimen. Do you want to confirm on a segment or issue based on molecular testing? As antisera becomes scarcer and more expensive, DNA testing will become more prevalent. That will probably make us rethink how we do things.

[Liz]

Absolutely John.

[conwaysbb]

We use the Sunquest blood bank system and each unit is brought in to the system by supplier, unit # and ISBT 128 product code so we can easily distinguish both units. I have decided, for the exact same reasons as mentioned here, to be consistent and not have too many exceptions, so we will be antigen typing each unit of a double red cell unit. As we have a large sickle cell population and tend to transfuse multiple units, it is to the patient's advantage (and to ours to a certain extent) to be transfused both units of a double red cell transfusion to reduce donor exposure (most of our multiple antibody patients ar sickle cell patients). We also give RH and K matched units to these patients and it helps when a unit of a double red cell collection is found to be that match. We just look in our inventory to see if we have the other unit available. It would be even better for our budget, if I didn't have to antigen type that second unit.

Again thank you all for you replies.

[conwaysbb]

John makes an excellent point about making the process simple and consistent. However, I don't think that means that there is only one answer here. A donor center might have easy access to donor specimens. If you are computerized, how does your computer system record the results? To the donation or to bag 1 or bag 2, depending on which is tested? Antigen testing by molecular methods would use the donor specimen. Do you want to confirm on a segment or issue based on molecular testing? As antisera becomes scarcer and more expensive, DNA testing will become more prevalent. That will probably make us rethink how we do things.

Since you mentioned molecular testing, has the FDA approved this technology to be used for resulting antigen typing on units? From my knowledge, molecular testing is still used for research only.

[Marilyn Plett]

I don't believe the FDA has licensed molecular testing for antigens. I believe at least two companies have submitted documents. There are a number of antigens for which there is no source of licensed antisera: Jsb, V, VS, U come to mind. There are also a few antigens for which the American Rare Donor Program will accept molecular testing as the sole test method since antisera sources are extremely limited or non-existent.

[heathervaught]

John makes an excellent point about making the process simple and consistent. However, I don't think that means that there is only one answer here. A donor center might have easy access to donor specimens.

You are absolutely right, Marilyn. As a donor center with a Reference Lab, we do perform certain antigen typing tests and post results to the Donation, not just to individual components. Some examples:

• A and B antigens
  
• D antigen
  
• C, c, E, e antigens (we can test for these using Donor samples on the Olympus)
  
• Any antigen tested only using molecular methods (Bio Array)
  

[BB1956]

Molecular testing is a whole different ball game with different procedures to follow. As long as the units are serologically typed, I agree with John and follow the KISS principle (Keep it simple stupid) whenever possible. Whenever I change procedures or even consider changes, I take this principle into account. Many Transfusion Services do not have dedicated Blood Bankers 24-7. Deviations from the Norm can often be missed and result in serious consequences. The most common problems I find is a tech that "thinks" they know the procedure so they don't bother to look it up. By keeping things uniform there are fewer errors.

[Likewine99]

We type both units.

We have had the instance that Deny mentioned above, mislabeled unit.

We received 2 units from a dual red cell collection, same ISBT numbers but different product codes. One typed A neg (the correct type) and one typed O pos (the mislabeled one). I know it's rare but in the antigen typing world I would be conservative and say type them both.

[MARINA]

Patient safety and ease of employees not having to think about differences in rules, makes me side on testing both units. I have worked with both Meditech and Cerner and both require testing results for each individual unit.

[LIMPER55]

different product codes on each unit will require each unit to be typed

[vilma_mt]

My thoughts are to keep it simple. When you have a process and then try to define exceptions to that process it provides more opportunity for errors. It was the same concept we had with Autologous units. We were not required to do any infectious disease testing on them but it was easier and more consistant to treat all donor units the same than it was to try to keep track of the ones that did not need the testing.

While I certainly agree with the logic of not testing both bags of a double unit and I would lean towards all or nothing. If you are going to require the crossmatch for both bags then require everything otherwise you are leaving your staff open to confusion especially when pressed for time.

I agree! Also the slight chance of processing error (i.e. labeling)

[Mary**]

I agree. If you didn't type the second unit, it would remain in the Received Status and not move to the Available status in the Cerner computer.