IS with AHG crossmatch

[Lcsmrz]

I vaguely remember a post from months ago, regarding a need to perform IS phase along with an AHG crossmatch.

The posting had to do with some newsletter stating that CLIA demands a test for ABO incompatibility, to which an AHG crossmatch is particularly insensitive. If I remember correctly -- always suspect in my old age -- the discussion scientifically understood the rationale, but disagreed with the requirement. A subsequent article (somewhere) studied the ability of an AHG crossmatch to detect ABO incompatibility, and the numbers showed that (surprise!) it does a very poor job.

Does anyone remember the AABB or CLIA commenting on this?

[David Saikin]

I remember the original post, but not thte subsequent one. I validated my AHG xm to verify ABO compatibilty. Seems to work well for me. The only time that it did not was in a pt that did not have a demonstrable back type. the IS xm did not work for this patient.

[L106]

Lcsmrz -

What you have written is correct. I don't know if AABB or CLIA spells it out, but Item # TRM.40650 in the CAP Inspection Checklist says:

"For allogeneic units, is a major serological crossmatch performed to detect serologic incompatiblity?

NOTE: Under certain circumstances, a transfusion service may elect to omit the antiglobulin phase of the serologic crossmatch. The antiglobulin test may be omitted if the antibody screen is negative and there is no history of detection of unexpected antibodies. Neverthles, a procedure to demonstrate ABO incompatiblity, either a major serological crosmatch or a validated computer system, is required. The computer crossmatch may not be used if the patient has, or has had, evidence of clinically significant alloantibodies. Typing, screening and crossmatching of neonates can be abbreviated if a specific protocol is available."

CAP doesn't come out and use the terminology "immediate spin crossmatch", but my interpretation of the paragraph above is that you must do either a serologic crossmatch or an electronic/computer crossmatch. If you do a serologic crossmatch, you may omit the AHG phase in certain circumstances, but you can't omit the immediate spin phase.

Donna

[KKidd]

If your compatibility table in the computer has been sufficiently validated, would this qualify? It seems like it would, even if you are not technically performing electronic corssmatches. This seems to meet the intent. We're not CAP accredited, so I cannot speak directly to their requirements.

When we switched to gel, we validated the crossmatches using ABO incompatible units and had no problems.

[L106]

If your compatibility table in the computer has been sufficiently validated, would this qualify? It seems like it would, even if you are not technically performing electronic corssmatches. QUOTE]

You know, I think that might be debatable. On one hand, the CAP wording says "validated computer system", so relying on your validated compatibility table would seem to meet that criteria.

However, I could envision that some inspectors/assessors would say what you are doing constitutes "electronic crossmatching", so they would expect you to have all the appropriate documentation/ validation for your electronic crossmatching.

Bottom line: Obviously, I don't know.

[clmergen]

We don't do an immediate spin XM with our AHG crossmatches. We rely on the computer's compatibility tables only. AABB didn't comment on this last month. CAP is coming in the next 2 months......

[L106]

We don't do an immediate spin XM with our AHG crossmatches. We rely on the computer's compatibility tables only. AABB didn't comment on this last month. CAP is coming in the next 2 months......

Let us know what your CAP inspection said about relying on the computer's compatibility tables, OK?

[Ajac]

I think ruling/comment was from CLIA in July–August 2009 edition of the CLIA Network Newsletter. I only saw University of Iowa's comments about it, not the actual newletter. If anyone can get the newletter, it might be worth checking. It said that gel xmatches didn't work alone to confirm ABO compatibility. You had do some additional confirmation.

[Eagle Eye]

Gel crossmatch is only AHG phase but my computer system is validated to check ABO incompatibility eventhough we do not use computer crossmatch. In reality if you are using computer crossmatch and patient has antibody ...you have to do serological crossmatch. If question comes up during our next inspection.........I would prove to my inspector that our computer system is designed to detect ABO incompatibility. eg. if I am trying to crossmatch A Pos unit to O pos, our computer system doesn't allow it...

[Vic]

We don't do an immediate spin XM with our AHG crossmatches. We rely on the computer's compatibility tables only. AABB didn't comment on this last month. CAP is coming in the next 2 months......

We have gone through our last 3 CAP inspections not performing IS crossmatches. We only use the gel for routine crossmatches and we have yet to be cited. Our computer system will also not allow ABO incompatible allocations.

[Yanxia]

I remember in the 15th edition of AABB technical manual about ABO subtype detection said that we use IS first then AHG to confirm the weak A or B antigens.

I think this can prove AHG can detect A or B reaction and it is more sensitive than IS.

[David Saikin]

Just because your computer xm tables are validated DOES NOT mean that your system qualifies to perform electronic crossmatches. The FDA has other criteria incumbent on a computer system before it is acceptable to run the eXM.

[shelleyk482]

The 16th edition of the Technical Manual states (pg 453) "Although tube and column agglutination AHG crossmatches will also detect ABO incompatibility, the AHG crossmatch in solid phase may not. An additional procedure is required to verify ABO compatibility, such as the IS or computer crossmatch". So my understanding of this is that the only time you need to do the IS in addition to the AHG phase is if you are using solid phase technology to do your crossmatch.

[falgunijoshi]

It is CLIA requirements to perform IS x-match when AHG x-match is being done.

[shelleyk482]

In which section of the CLIA regulations did you find this requirement? I've scanned through document and evidently missed it. Thanks.

[Mary**]

What about when you are doing gel crossmatches.

[Sue Miller]

I suspect that noone has been cited by CAP because CAP is a peer inspection and most of us do not think an IS crossmatch is required when you are performing an AHG crossmatch and entering results in a LIS.

[Kashmira patel]

I suspect that noone has been cited by CAP because CAP is a peer inspection and most of us do not think an IS crossmatch is required when you are performing an AHG crossmatch and entering results in a LIS.

We recently completed our joint AABB/CAP inspection, though the question of IS crossmatch in addition to Gel crossmatch was brought up for patients with antibodies referencing CLIA regulations, there were no citations. Our computer system is validated for electronic crossmatches and we perform gel crossmatches only for patients with antibodies.

[rravkin@aol.com]

Lcsmrz,

It seems that if you are trying to omit the IS crossmatch when performing an AHG crossmatch your computer must be validated to catch ABO incompatiblity. In the abscence of this type of computer system it seems that your are obligated to continue with the additional IS crossmatch. So if we are performing an AHG crossmatch and we aquire incompatible results how can we distiguish the cause between ABO and other groups based soley on the AHG crossmatch. I think that this is where the IS crossmatch is beneficial because it is here that an ABO incompatibility is most probable, as opposed to the AHG crossmatch.

[Liz]

What about when you are doing gel crossmatches.

Gel is fine as it is considered column and according to the AABB : "Although tube and column agglutination AHG crossmatches will also detect ABO incompatibility, the AHG crossmatch in solid phase may not."

Liz

[Mary**]

Thanks.

[jcdayaz]

We use gel for almost all our testing. We do not even IS crossmatch anything anymore (pretty much, although I may be forgetting something right now). We computer crossmatch (validated computer system) every patient that has no history of antibodies or other issues.way ti

We have flown through multiple CAP and AABB inspections with no issues noted.

Although it is uncomfortable to us who are "old school", computer crossmatching is the way to go when you have a patient with no other issues and a computer system that will SCREAM at you if an error is made.

[jcdayaz]

We use gel for almost all our testing. We do not even IS crossmatch anything anymore (pretty much, although I may be forgetting something right now). We computer crossmatch (validated computer system) every patient that has no history of antibodies or other issues.way ti

We have flown through multiple CAP and AABB inspections with no issues noted.

Although it is uncomfortable to us who are "old school", computer crossmatching is the way to go when you have a patient with no other issues and a computer system that will SCREAM at you if an error is made.

WHAT THE HECK???? "way ti"...what is that? I have apparently adopted Malcolm's spelling "issues".

[rravkin@aol.com]

Gel is fine as it is considered column and according to the AABB : "Although tube and column agglutination AHG crossmatches will also detect ABO incompatibility, the AHG crossmatch in solid phase may not."

Liz

Liz,

Thanks for the info. But I am still having trouble understanding how we distinguish ABO incompatibility with incompatibility based on other blood groups when our AHG crossmatch is incompatible. In practice I use GEL to perform AHG crossmatch and if it comes up incompatible the last possibility I consider is ABO incompatibility; of course we still do the IS crossmatch in parallel.

[Liz]

Liz,

Thanks for the info. But I am still having trouble understanding how we distinguish ABO incompatibility with incompatibility based on other blood groups when our AHG crossmatch is incompatible. In practice I use GEL to perform AHG crossmatch and if it comes up incompatible the last possibility I consider is ABO incompatibility; of course we still do the IS crossmatch in parallel.

Oh, I missed to say that we repeat the ABO Blood type (slide method) with every Crossmatch or IS as the case presents itself. So CAP love us, we end up doing a total of 3 ABOs on all donors and patients.

Liz