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Immediate spin crossmatch


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Hi everyone,

A few years ago many Transfusion Services started performing an immediate spin crossmatch in addition to IgG gel crossmatch even though the Transfusion Service had a validated computer system to detect ABO incompatibility. Is anyone not doing an immediate spin crossmatch in addition to IgG gel crossmatch when the patient has a clinically significant antibody (or history of) when you have a validated computer system to detect ABO incompatibility? If so, why not? has an inspector had a problem with this? what have you based your decision (CAP, AABB)?

thanks for your input

JB

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We are not doing IS xm with our gel crossmatches except during computer downtime. Here is what I put in the XM procedure to justify this course. AABB & JC both due this summer so we will see.

Whereas:

• Sensitivity: Immediate Spin crossmatch can not detect 100% of ABO incompatible units due to low titer of antibodies or weak expression of the antigens

• Specificity: Immediate Spin crossmatch gives some false positive results (cold agglutinins, rouleaux etc.)

• Cold antibodies can cause false positives with immediate spin crossmatches, presenting a quandary on how to manage a unit that is incompatible at IS and compatible at AHG. Warming the sample to avoid the cold antibody might reduce the reactivity of the ABO antibodies as well. This false positive could happen even with an O unit when ABO incompatibility is not even possible.

• HBB [our BBIS] contains algorithms that verify the ABO compatibility of all products selected and our validation shows this to have 100% sensitivity for detecting ABO incompatible units and 100% specificity for avoiding false positive results—both an improvement over immediate spin testing.

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We had an FDA inspecter (or maybe a JCAHO) bring this up a few years ago, now we are doing the IS in addition to the AHG.

I believe the thinking was that with just a AHG, there is no RT test to r/o an ABO incompatibility. We did come across a case from another institution where an ABO incompatible unit did NOT show up at AHG, so it does seem to be a good idea.

Scott

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We are in the process of dropping the IS crossmatch when doing gel crossmatches. But we validated the procedure first. We tested A, B, AB and O plasma in Gel with A, B, AB and O cells to demonstrate that the gel technique will detect ABO incompatibilites.

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We are in the process of dropping the IS crossmatch when doing gel crossmatches. But we validated the procedure first. We tested A, B, AB and O plasma in Gel with A, B, AB and O cells to demonstrate that the gel technique will detect ABO incompatibilites.

Have you tested patients with very weak back types (+1)? We tested a few patients with +1 reverse types using ABO incompatible units and they were compatible. Seeing that made us add the immediate spin again to the gel crossmatch. If the immediate spin is incompatible due to a cold, the units type must be ABO re-typed when performing the crossmatch.

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We are not doing IS xm with our gel crossmatches except during computer downtime. Here is what I put in the XM procedure to justify this course. AABB & JC both due this summer so we will see.

Whereas:

• Sensitivity: Immediate Spin crossmatch can not detect 100% of ABO incompatible units due to low titer of antibodies or weak expression of the antigens

• Specificity: Immediate Spin crossmatch gives some false positive results (cold agglutinins, rouleaux etc.)

• Cold antibodies can cause false positives with immediate spin crossmatches, presenting a quandary on how to manage a unit that is incompatible at IS and compatible at AHG. Warming the sample to avoid the cold antibody might reduce the reactivity of the ABO antibodies as well. This false positive could happen even with an O unit when ABO incompatibility is not even possible.

• HBB [our BBIS] contains algorithms that verify the ABO compatibility of all products selected and our validation shows this to have 100% sensitivity for detecting ABO incompatible units and 100% specificity for avoiding false positive results—both an improvement over immediate spin testing.

Same here. The computer system detects ABO incompatibility much better than an immediate spin xm.

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Did you test same donor & patient by tube method? Was is compatible or not compatible?

Have you tested patients with very weak back types (+1)? We tested a few patients with +1 reverse types using ABO incompatible units and they were compatible. Seeing that made us add the immediate spin again to the gel crossmatch. If the immediate spin is incompatible due to a cold, the units type must be ABO re-typed when performing the crossmatch.
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Did you test same donor & patient by tube method? Was is compatible or not compatible?

No we did not test in tube. The patients were crossmatched on the ProVue using the anti-IgG card. The ProVue interpretations were compatible and when the wells were visually checked they looked negative. At the time we were not doing the immediate spins and we added it back into our crossmatch procedure when doing the extended crossmatches. There was a post on the CLIA Corner about this about a year ago and the answer was you have to test patient serum or plasma with the donor unit for ABO incompatibility per CMS guidelines.

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According to the letter from Ortho dated 1/28/11, "the overall conclusion was that since the MTS anti-IgG gel card does not contain FDA approved labeling for detection of IgM antibodies, it is not adequate to demonstrate ABO incompatibility." Further along the letter continues: "It has been brought to our attention that some ID-MTS Gel customers have been cited as out of compliance with CLIA regulations.......even in situations when the customers have performed internal validation studies demonstrating the the MTS anti-IgG crossmatch will identify ABO incompatibilities....". If you have software in place to comply with electronic XM requirements you wouldn't necessarily need to do an IS XM, but despite internal validation studies, an over- zealous inspector may still decide to go along with the strict interpretation of the CLIA regs.

We do the IS XM and wait for Ortho to do the required validation studies on a large enough cohort to make an IgG XM valid for detection of ABO incompatibilities.

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I know someone that did testing of Ortho MTS gel for ABO incompatibility and found that it failed sometimes, mostly with group B patients.

I believe that the CMS rules are that the patient must be tested in a way that detects ABO incompatibility. I don't believe it stipulated that the test be serological. The computer algorithms will not miss the incompatibility if the reverse antibody is very weak but the IS xm could, therefore the computer is the more sensitive (and specific) test. We see both AABB and JC this summer so I will let you know how it goes.

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We are in the process of dropping the IS crossmatch when doing gel crossmatches. But we validated the procedure first. We tested A, B, AB and O plasma in Gel with A, B, AB and O cells to demonstrate that the gel technique will detect ABO incompatibilites.

I have found pts with weak reverse typings will give compatible xms in IgG gel when ABO incompatible rbcs are used. The FDA bases its requirement for ISxm when using gel on the statement in the pkg insert for IgG gel which states that this product will not detect all IgM abs.

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I have found pts with weak reverse typings will give compatible xms in IgG gel when ABO incompatible rbcs are used. The FDA bases its requirement for ISxm when using gel on the statement in the pkg insert for IgG gel which states that this product will not detect all IgM abs.

Hi David,

This is what I found from the FDA - 606.151 Compatibility testing.

© Procedures to demonstrate incompatibility between the donor’s cell type and the recipient’s serum or plasma type.

I cannot find the FDA requirement for ISXM. Can you post it?

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There is no guidance document . . . I think this came up at one of the AABB sessions. There is also another session somewhere on this site that has the info. There is a post from August 2011 about this issue under HOT TOPICS.

Edited by David Saikin
added more info
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I think the point here is that gel testing is not reliable to show ABO incompatibilities. Not sure if the FDA ever put that into a reg, but there is something somewhere by AABB or somebody where it came up and an opinion was issued on it.

Thing is, the reg says "procedures to demonstate incompatibility". If you are not using a method that is reliable for ABO incompatabilities, I would say you are in violation of the reg.

At least, that's the gist of what our FDA inspector told us last year.

Scott

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  • 2 years later...

I know someone that did testing of Ortho MTS gel for ABO incompatibility and found that it failed sometimes, mostly with group B patients.

I believe that the CMS rules are that the patient must be tested in a way that detects ABO incompatibility. I don't believe it stipulated that the test be serological. The computer algorithms will not miss the incompatibility if the reverse antibody is very weak but the IS xm could, therefore the computer is the more sensitive (and specific) test. We see both AABB and JC this summer so I will let you know how it goes.

 

The following is an abstract that was presented at the October 2013 AABB meeting in Denver.  I thought it was interesting and remembered this subject had been discussed here, so I dug up this thread and am posting this....

 

SP219 Detection of ABO Incompatibility in the Extended IgG Gel Crossmatch

R M Barrett1,2(Rachelle.Barrett@salemhospital.org), T Kasper1. 1Blood Bank, Salem Health Laboratory, Salem, OR, United States; 2SBB Program, University of Texas Medical Branch, Galveston, TX, United States

Background/Case Studies: AABB Standard 5.15.1 states: “The crossmatch shall use methods that demonstrate ABO incompatibility and clinically significant antibodies to red cell antigens and shall include an antiglobulin test.” When a clinically significant antibody other than ABO is detected during pretransfusion testing, the crossmatch is performed using the same method used in detection. Many extended crossmatch methods do not have an immediate spin reaction. The testing facility for this study uses MTS IgG Gel cards for detection of clinically significant antibodies other than ABO in extended crossmatch. To meet this standard, an immediate spin crossmatch is required in addition to this extended crossmatch. If it could be proven ABO incompatibility is detectable even by methods not designed for such purposes, the extra step of completing an immediate spin crossmatch in the case of the extended crossmatch could be eliminated for the sake of efficiency. Study Design/Methods: Twenty randomly selected samples of each ABO blood type were crossmatched with known ABO incompatible donors at tube immediate spin and on MTS IgG gel cards. Known ABO compatible crossmatch donors were used as controls. Randomly selected samples were also tested for complement activity using commercial anti-c3b-c3d in tube. Results/Findings: ABO incompatible crossmatch was apparent 100% of the time at immediate spin for all samples tested. Type O and A samples demonstrated incompatibility in 100% of samples tested on MTS IgG gel. Type B samples gave negative reactions on IgG gel in 15% of samples tested. Furthermore, type B samples had significantly lower grade reactions on gel as compared with Type O and A samples. Samples that were negative on gel were also negative for complement activity. Positive gel reactions correlated with positive complement in the few samples tested. Conclusion: The clinical significance of the ABO antibodies made by the % of patients testing negative in gel is questionable. If the ability to fix complement is diminished for these antibodies, are these patients then protected from hemolytic transfusion reactions when exposed to type incompatible blood? Until further study determines the clinical significance of these differences in antibody activity, this study suggests completing an immediate spin crossmatch in addition to extended crossmatch methods when extended crossmatch testing methods do not already include an immediate spin reaction.

Disclosure of Commercial Conflict of Interest

R. M. Barrett: Nothing to disclose; T. Kasper: Nothing to disclose

Disclosure of Grants Conflict of Interest

R. M. Barrett: Nothing to disclose; T. Kasper: Nothing to disclose

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I understand that the gel IgG crossmatches cannot adequately detect ABO incompability per manufacturer's instructions and regs, but what about using the electronic controls of a validated system to detect ABO incompability in addition to the gel crossmatch?

 

AABB Standard 5.15.1 states: “The crossmatch shall use methods that demonstrate ABO incompatibility and clinically significant antibodies to red cell antigens and shall include an antiglobulin test.”

 

My opinion: electronic controls monitor ABO incompability and clinically significant antibodies. Check.

                  IgG crossmatches are an antiblobulin test. Check, check.

 

Standard met.

Edited by lkellar
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aaBB Stds. 29th Ed.

5.16.2

"Use of a computer  to detect ABO compatibility

If the use of a computer system is used as a method to detect ABO compatibility, the following requirement shall be met."

 

What follows are the requirements for electronic crossmatch.

If the use of a computer is good enough for the EC then it is good enough to check ABO compatibility when entering results for an AHG crossmatch. All of the BB computer systems I have seen check the ABO of the patient and donor and prevents the issue of ABO compatible units, providing that the tables are set up correctly and validated.

Of course, if you don't have BB computer system you have to do the IS. However, even if you are not doing electronic crossmatches  the system should still have validated tables to prevent the allocation and issue of ABO (and Rh) incompatible units. We have written our SOPs to cover this in the event the system is down.

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I just thought it was interesting that it was the group B samples that gave negative (compatible) IgG Gel crossmatches with incompatible blood, just as Mabel remembered.  And, as Mabel said, the electronic crossmatch could be more sensitive than the IS crossmatch.  :)

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We do not do an IS XM when we have to do gel XM.  Our computer system will stop us from issuing non compatible blood. Also, for the last 3 years I have been doing method comparisons between gel and IS XM showing that they correlate.  Gel has picked up incompatibilities in ABO every time. 

 

My inspectors have been satisfied to this date.  I'm due for another CAP any day, so I will let you know if they now have problems with it  :)

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  • 1 month later...

We do not do an IS XM when we have to do gel XM.  Our computer system will stop us from issuing non compatible blood. Also, for the last 3 years I have been doing method comparisons between gel and IS XM showing that they correlate.  Gel has picked up incompatibilities in ABO every time. 

 

My inspectors have been satisfied to this date.  I'm due for another CAP any day, so I will let you know if they now have problems with it  :)

 

HI Michaele, without going to much into the LIS world/language - I am wondering which LIS you use and how you set your system up to NOT do the IS XM. Logically like everyone else is saying the computer is validated to not let an ABO incompatibilty slip pass but our rules are set up as such we can't move on without entering IS grid results....? Any suggestions?

 

Also, we are not electronically crossmatching yet but even if we were to go there I have heard the the rules are set in the truth tables to not allow electronic crossmatch if AHG crossmatch is required due to positive screen....any body have any suggestions for how to set up rules to just let the computer be the ABO crossmatch but not miss doing the IgG portion of the crossmatch? 

 

Good Topic no matter what type of AHG crossmatch you're doing ...

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Megan,

 

We use Meditech and when a patient has an antibody we don't do an IS, because our LIS is validated for ABO incompatibility.  We order XM GEL and enter our results there.  In the field for XM IS we just enter TNP(Test not performed.)  As several people have commented, if the computer system is down, we must do an IS XM for ABO incompatibility.

 

Hope that helps.

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