Postive IS/AHG Procedure anyone??

[Packer Banker]

I'm hoping someone is bored this Christmas/New Year's vacation, and can help me get a jump start on a project. I've been sitting on this one for some time!

Our current procedure states that if Ab screen results look as though a cold antibody may be present (Immediate Spin screen positive, AHG negative or positive), a "cold mini panel" with cord cells, etc. must be done, in the room temp, 18 degree C, and 4 degree C phases. This is in addition to a regular antibody work-up. The theory is that "you have to know what you're pre-warming away". It seems it's necessary to determine whether it's Anti-I, Anti-IH, etc. . They're also concerned that an Anti-E might be pre-warmed away. I know that happens, but how does ANY procedure cover that??!! The current procedure obviously is a tedious process that to me, has no merit.

Our pathologist is typically VERY cautious, not wanting to miss anything. But I think the major reason this is done, is that our staff is mostly a cross-trained staff that doesn't work too often in the blood bank. Many don't have the basics of blood banking deeply ingrained, so they're trying to avoid a missed antibody. Just a guess?? Does anyone have some sort of flow chart already made up, that guides you through what to do, starting with Ab screen results?

Oh- did I fail to mention we also do patient auto controls (patient serum with patient RBCs) with every screen? So, one of the possible scenarios is that only the auto is positive. (I'd also like to delete THAT from our procedure. Wouldn't we rather not know??) Please forgive my negativity here, but this has been a thorn in my side for some time!

[Malcolm Needs ☆]

I'm hoping someone is bored this Christmas/New Year's vacation, and can help me get a jump start on a project. I've been sitting on this one for some time!

Our current procedure states that if Ab screen results look as though a cold antibody may be present (Immediate Spin screen positive, AHG negative or positive), a "cold mini panel" with cord cells, etc. must be done, in the room temp, 18 degree C, and 4 degree C phases. This is in addition to a regular antibody work-up. The theory is that "you have to know what you're pre-warming away". It seems it's necessary to determine whether it's Anti-I, Anti-IH, etc. . They're also concerned that an Anti-E might be pre-warmed away. I know that happens, but how does ANY procedure cover that??!! The current procedure obviously is a tedious process that to me, has no merit.

Our pathologist is typically VERY cautious, not wanting to miss anything. But I think the major reason this is done, is that our staff is mostly a cross-trained staff that doesn't work too often in the blood bank. Many don't have the basics of blood banking deeply ingrained, so they're trying to avoid a missed antibody. Just a guess?? Does anyone have some sort of flow chart already made up, that guides you through what to do, starting with Ab screen results?

Oh- did I fail to mention we also do patient auto controls (patient serum with patient RBCs) with every screen? So, one of the possible scenarios is that only the auto is positive. (I'd also like to delete THAT from our procedure. Wouldn't we rather not know??) Please forgive my negativity here, but this has been a thorn in my side for some time!

I'm afraid that I don't have such a flow chart, but do agree with your arguments concerning this procedure being a complete and utter waste of time Packer Banker.

The first thing I would ask your Pathologist is, what temperature do the extremities of the human body (fingers, toes, nose, etc) reach when cold? I would be surprised if, in a hospital ward or operating theatre where, presumably, the transfusion is taking place, the extremities reached as low as 30oC. Therefore, if the "cold" antibody does not react at 30oC, it is clinically irrelevant.

Secondly, what on Earth is the relevance of the specificity? If the antibody is anti-I, is he/she going to order adult ii blood? If the antibody is anti-HI, is he/she going to order Oh blood? I know what the Consultant-in-Charge of our National Frozen Blood Bank would tell her/him if she/he tried to order such blood in the UK (and I would tell you, but for the fact that this post would be taken out by the moderators)!!!

Thirdly, why on Earth are you forced to perform an immediate spin screen in the first place, when you also perform (quite correctly) an IAT screen? All this does is detect irrelevant "cold" antibodies, whether they be auto- or allo- (I am thinking of such specificities as a "cold-reacting" anti-M of limited thermal amplitude) and force you to perform all this extra work for no gain whatsoever.

I would, were I cheeky enough, also suggest to your Pathologist the she/he has a word with her/his peer Pathologists, such as the Pathologist-in-Charge of your Reference Laboratory, and get a bit of advice (or reads a few up-to-date text books), but I'd probably get the sack for asking and so, I suggest would you!!!!!!!!!!!

Such dinosaurs should not be let anywhere near a Blood Bank Laboratory, let alone be put in charge!!!!

:mad::mad::mad::mad::mad:

[David Saikin]

Like Malcolm says - why are you doing IS ab screens? You don't want to find those cold abs. However, if you do IS crossmatches, rarely you will be surprised by an incompatibility due to a cold moiety. THEN you would have to do something, but to do it routinely seems a waste of time and resources (not to mention 30 year old blood bank mentality). I will tell you, however, that I do reference work for facilities that have the same policies.

[RR1]

If you can collect stats on your current processes and for the IS screens that only showed cold antibodies, in addition to any info on delays in blood provision caused by having to investigate these, you may be able to agree on changing procedures.

Surely the current process is more difficult for the cross-trained staff to follow through, and needs to be simplified for them too.

[Malcolm Needs ☆]

If you can collect stats on your current processes and for the IS screens that only showed cold antibodies, in addition to any info on delays in blood provision caused by having to investigate these, you may be able to agree on changing procedures.

Surely the current process is more difficult for the cross-trained staff to follow through, and needs to be simplified for them too.

Much as I am loathed to say it, these are very good points!

:tongue::tongue::tongue::tongue::tongue::tongue:

[adiescast]

I would definitely get rid of the immediate spin screen for routine samples, along with the auto control with the screen, and the specific identification of the cold antibody. We do a cold screen only at RT and 4 degrees. I don't see the purpose for the 18 degree reading. I could not find the cold screen procedure in the current Technical Manual, which should tell us something about the industry standard. The only time we do a cold screen is if the antibody screen is positive at 37 or AHG, we can't find a specific antibody identification, and we want to pre-warm (that should give John Judd heart failure!). I think it is important to know that there is in fact a cold antibody present before you pre-warm. I have seen samples for which the tech wanted to pre-warm and the cold screen was not reactive. Bad idea...

Of course, lots of perfectly normal people are walking around with cold reactive antibodies that don't hurt anything.

To go along with Rashmi's post, in the Technical Manual, 16th edition, the following statement is made about antibody detection:

The goals of antibody detection testing are as follows:

To detect as many clinically significant antibodies as possible.

To detect as few clinically insignificant antibodies as possible.

To complete the procedure in a timely manner.

The process you describe does not meet these goals. Rashmi's suggestion will allow you to provide proof of that.

Also in the Technical Manual, 16th edition:

For transfusion recipients, tests for unexpected antibodies use unpooled reagent red cells and a method that detects clinically significant antibodies. The procedure includes an antiglobulin test preceded by incubation at 37 C

or an equivalent test system.

Of course if you chnged your routine test to CAT (gel) or solid phase, you could also get rid of the immediate spin problem.

Just my two cents worth...

[L106]

Our current procedure states that if Ab screen results look as though a cold antibody may be present (Immediate Spin screen positive, AHG negative or positive), a "cold mini panel" with cord cells, etc. must be done, in the room temp, 18 degree C, and 4 degree C phases. This is in addition to a regular antibody work-up. !

All previous posters have provided a variety of very useful suggestions. I will add my two cents on the minor topic of investigating whether the antibody problem is a cold autoantibody.

Rather than the laborious workup you explained in the above quote, if we think a patient's antibody problem is due to a cold autoantibody, we set up the 3 (or 2, depending on what you are using) Antibody Screening Cells and an Auto Control. (Two drops of patient plasma and one drop of test cells.) Incubate the four tubes in the refrigerator (approx 4 C) for 15-30 minutes, spin & read.

If all tubes react 3+ or 4+, we report it as "Cold Autoantibody" (and do a RESt adsorption or prewarm)

If the autocontrol is Negative, it's not a cold autoantibody problem.

If the reactions are 1+ or weaker, it's not a cold autoantibody problem.

If the reactions are 2+, it's probably not a cold autoantibody.

Also, you will be fine if you drop the autocontrol. (But do set one up if you have to do an antibody identification.)

[Packer Banker]

Thanks for your input. I'm hoping to come up with a flow chart that all can use easily, and at the same time help our pathologist see that all paths lead to the same result!! I only work weekends as a generalist with bare bones staff, of course, so am thinking this is a home project while kids are napping. I want it to be perfect (ok, close anyway) before presented to her, so she doesn't just dismiss it as nonsense. We waste SO much time with this- when we only have 2 techs on staff in the entire lab, it's a little ridiculous to have blood bank take up our time with this mess.

I used to work at a large university hospital (left 6-7 years ago), where we did the IS phase of the screen also. I'm curious to know how many don't now- anyone??

[Steven Jeff]

Hi Jennifer

In answer to your question, No we do not use IS in our antibody screens, nor do we set up an autocontrol.

I might suggest that you could ask your question by setting up a poll on this forum. However, don't ask me how as I am still relatively new to this site.

Regards

Steve Jeff

[RR1]

Thanks for your input. I'm hoping to come up with a flow chart that all can use easily, and at the same time help our pathologist see that all paths lead to the same result!! I only work weekends as a generalist with bare bones staff, of course, so am thinking this is a home project while kids are napping. I want it to be perfect (ok, close anyway) before presented to her, so she doesn't just dismiss it as nonsense. We waste SO much time with this- when we only have 2 techs on staff in the entire lab, it's a little ridiculous to have blood bank take up our time with this mess.

I used to work at a large university hospital (left 6-7 years ago), where we did the IS phase of the screen also. I'm curious to know how many don't now- anyone??

Hi Jennifer, trying posting your question as a poll then you'll have a better indication of figures.

[janet]

We would warm that positive I.S. crossmatch - if negative after the warming then it must have been a cold, an insignificant cold if the 37C antibody screen didn't pick it up!

If it was still positive after warming I would suspect rouleax and do a saline replacement.

Compatible blood is usually found within 10 minutes using these two trouble shooting methods.