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Detecting ABO incompatibility with Validated Computer System


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Our facility uses Softbank and we have recently begun using the Ortho Vision.  Vision is not licensed to perform IS crossmatches  using a buffered gel card.  I know that a few years back there was controversy over whether the validated computer system could be substituted for the immediate spin crossmatch and wording for CAP and AABB standards has changed to specify criteria to use the computer system to detect an ABO incompatibility when selecting blood for patients.  My question is:  Has anyone eliminated the IS XM for patients who have a history of (or currently demonstrating) antibodies, perform serological XM incubating at 37, perform reading at AHG phase and allow your validated computer system to detect possible ABO incompatibility?  If yes,  have you been inspected by CAP and/or AABB and was there an issue with it?

I had a great deal of difficulty trying to word this question - since we have just implemented the Vision, it seemed like a good time to look at whether we needed to do the ISXM  for our serologically crossmatched patients.  My medical director agreed but I wanted to see if anyone has gone this route and gone through an inspection before I jump into the frying pan.

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We use manual gel for AHG crossmatches (not IS).  Our procedure states that the computer will detect ABO incompatibility.  The only time we would add an IS XM is  during computer downtime.  We have not been cited for this.

"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. Nevertheless, a procedure to demonstrate ABO incompatibility, either a serologic crossmatch 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 procedure is available.

TRM.40650

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9 hours ago, mollyredone said:

We use manual gel for AHG crossmatches (not IS).  Our procedure states that the computer will detect ABO incompatibility.  The only time we would add an IS XM is  during computer downtime.  We have not been cited for this.

I agree wholeheartedly with this! It's not what's done at my current lab (we do an IS XM with the gel XM), but it was the way I had implemented it at a previous blood bank.  We had no issues with the inspections.

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  • 2 months later...

I asked AABB to clarify and received this response:

Please refer to AABB Blood Banks and Transfusion Services Standard 5.16 Crossmatch section (30th edition).

 

Standard 5.16.1 states… “The crossmatch shall use methods that demonstrate ABO incompatibility and clinically significant antibodies to red cell antigens and shall include an antiglobulin test as described in Standard 5.14.3.”

 

Standard 5.16.1.1 states “If no clinically significant antibodies were detected in tests performed in Standard 5.14.3 and there is no record of previous detection of such antibodies, at a minimum, detection of ABO incompatibility shall be performed.”

 

Standard 5.16.2 states… “If a computer system is used as a method to detect ABO incompatibility, the following requirements shall be met:….”  See standards 5.16.2.1 – 5.16.2.5.

 

In summary, if you are doing an extended/Coombs crossmatch, you also need a method to demonstrate ABO incompatibility.  This is most often done by an immediate spin crossmatch.  Check your manufacturer’s instructions (Gel Cards, PeG, LISS, etc) to see if these reagents state that they also detect ABO incompatibility.  Most of the time they do not, which is why an immediate crossmatch is performed along with the antiglobulin test.

 

An electronic crossmatch can be done in lieu of the immediate spin phase if the requirements from Standards 5.16.2.1 – 5.16.2.5 have been met.  Keep in mind that an electronic crossmatch can only detect ABO incompatibilities and does not include an antiglobulin test.  So if the patient needs an extended/Coombs crossmatch, how is the ABO incompatibility being demonstrated?  Is the LIS validated to combine an electronic crossmatch with an extended/Coombs crossmatch (this is usually no), does the antiglobulin test detect ABO incompatibility (this is usually no), or do you need to do an immediate spin crossmatch?

 

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On 12/26/2017 at 6:02 AM, JLF said:

So if the patient needs an extended/Coombs crossmatch, how is the ABO incompatibility being demonstrated?  Is the LIS validated to combine an electronic crossmatch with an extended/Coombs crossmatch (this is usually no), does the antiglobulin test detect ABO incompatibility (this is usually no), or do you need to do an immediate spin crossmatch?

Our computer system is validated to detect ABO incompatibility before we do any kind of crossmatch.  If I pull out an A Pos PRBC for an O Pos patient and scan the unit, Meditech will tell me the unit is not ABO compatible whether I am performing an electronic crossmatch, immediate spin crossmatch, or an AHG crossmatch.

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As stated above, we use IS XM for ABO compatibility check only when the computer is down.  We have passed several TJC and AABB inspections since starting this. Here is a quote from my crossmatch procedure:

Whereas:

Sensitivity: Immediate Spin crossmatch will 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.

The 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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