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Re-testing antibody screens


RR1

Do you re-test antibody screens that give discrepent result to previous?  

72 members have voted

  1. 1. Do you re-test antibody screens that give discrepent result to previous?

    • Yes
      12
    • No
      29
    • Sometimes
      32


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If patient with negative antibody historically and we get all cell 1+ on ProVue with funny looking results(line @ top of gel and most of the cells @ bottom)...we do respun specimen and repeat by manual gel or in ProVue..

We do not repeat if antibody screen was positive in past and currently negative......we do not repeat.

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I always call it a lucky day when a patient with a history of antibodies has a negative screen. Since we are honoring all the known antibodies anyway, I never even considered retesting. However if last week the screen was 3+ and today it is negative, then I probably would repeat it, along with my controls, and possible redraw the patient. I guess my answer should be sometimes since each patient must be assessed individually. :eek:

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We do not repeat antibody screen if it was positive in the past, but negative now. Just crossmatch antigen-negative blood if it is a clinical significant antibody.

Repeat antibody workup when, (in case screening still positive),

(1) reaction pattern does not match the current one, and/or

(2) incompatible with antigen-negative blood.

CK Cheng, MSc, SBB(ASCP), CQA(ASQ)

Hong Kong

May 7, 2009

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We do not retest the negative Antibody Screen if it was positive in the past.

However, clmergen makes an excellent point.....it's important to keep an eye out for anything that seems wildly different, such as a 3+ antibody last week that isn't reacting this week. Redrawing the patient and retesting the samples is an excellent idea if there is something unusual that hints there may have been a patient, sample, or testing mix-up. (Good answer, clmergen!!)

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I agree with clmergen (and L106's assessment of clmergen's answer).

As a reference Service, we do a panel on each sample as a "first line of defence", as the presence of an antibody is why the sample has been sent to us in the first place. Some of these, of course, are DAT+ with free auto-antibody in the plasma.

However, what REALLY annoys us is when we receive a second or subsequent sample from the same hospital, when the patient was DAT+ with free auto-antibody in the plasma, and on this occasion the DAT is negative or positive, but there is no longer free auto-antibody (or alloantibody) in the plasma. Very often this is because they have put on to their computer, "Send to the Reference Laboratory" and have not tested the current sample themselves at all before referral.

Excuse the pun, but this makes my blood boil.

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Just to add an additional scenario: if you do check a discrepancy, would you check the sample on ALL of your analysers- (and possibly a manual method) just to show there is performance consistancy ?

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I agree with clmergen (and L106's assessment of clmergen's answer).

As a reference Service, we do a panel on each sample as a "first line of defence", as the presence of an antibody is why the sample has been sent to us in the first place. Some of these, of course, are DAT+ with free auto-antibody in the plasma.

However, what REALLY annoys us is when we receive a second or subsequent sample from the same hospital, when the patient was DAT+ with free auto-antibody in the plasma, and on this occasion the DAT is negative or positive, but there is no longer free auto-antibody (or alloantibody) in the plasma. Very often this is because they have put on to their computer, "Send to the Reference Laboratory" and have not tested the current sample themselves at all before referral.

Excuse the pun, but this makes my blood boil.

I know what you mean, MN, but try to not let it get to you. The hospital techs who are sending you those samples are more than likely frightened to death of "Reference Lab" samples, and antibodies. You know there are blood bankers and non-blood bankers, and no in-betweens. If on the other hand, this patient was a known Reference Sample, and the hospital techs wasted some of the precious sample by performing an ABO/Rh and Antibody Screen, only to have it turn out positive yet again before they sent it to you - and this time this patient had developed an additional allo, or two, you'd be wishing you had some extra serum! :rolleyes: Just have a little mercy on them, they mean well, they're just scared!

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Hi There Hi-Freq,

I agree with you entirely, and without reservation, that there are blood bankers and non-blood bankers, and that even some very experienced people within the blood bank can, in fact, be non-blood bankers when it comes to samples with antibodies present. Having said that, however, we ask them to ask the doctors/phlebotomists to take sufficient samples so that tests can be performed at the Hospital prior to submission, and to hold some back from this sample, so that they can cross-match when we supply them with antigen negative blood.

I realise that the fact that we ask them to ask the doctor/phlebotomist to do this does not mean that they will recieve such samples, but there are times when we receive three samples on the same patient, find that the DAT is now negative, or that the antibody is still an "easy" monospecific, and we then telephone them with the results, only to find that they have sent us all the samples and they have none left with which to cross-match.

I wouldn't mind, but some of these occasions have occurred in hospitals (during the day) where the chief in blood bank is ex-Reference staff themselves.

I DO TRY TO HAVE MERCY ON THEM, BUT I NEED A RANT SOMETIMES TO RELIEVE THE PRESSURE!!! CONTRARY TO WHAT MY FRIENDS AND COLLEAGUES FREQUENTLY SAY - I'M HUMAN.

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Hi There Hi-Freq,

I agree with you entirely, and without reservation, that there are blood bankers and non-blood bankers, and that even some very experienced people within the blood bank can, in fact, be non-blood bankers when it comes to samples with antibodies present. Having said that, however, we ask them to ask the doctors/phlebotomists to take sufficient samples so that tests can be performed at the Hospital prior to submission, and to hold some back from this sample, so that they can cross-match when we supply them with antigen negative blood.

I realise that the fact that we ask them to ask the doctor/phlebotomist to do this does not mean that they will recieve such samples, but there are times when we receive three samples on the same patient, find that the DAT is now negative, or that the antibody is still an "easy" monospecific, and we then telephone them with the results, only to find that they have sent us all the samples and they have none left with which to cross-match.

I wouldn't mind, but some of these occasions have occurred in hospitals (during the day) where the chief in blood bank is ex-Reference staff themselves.

I DO TRY TO HAVE MERCY ON THEM, BUT I NEED A RANT SOMETIMES TO RELIEVE THE PRESSURE!!! CONTRARY TO WHAT MY FRIENDS AND COLLEAGUES FREQUENTLY SAY - I'M HUMAN.

Well, this is a good place to rant and let off steam! I feel your pain! I know all too well how frustrating it can be. Makes you wonder how some of them made it through Med Tech school. (some, not all). Let me ask, when it's an easy monospecific, and they've sent you all the sample, do you then have to do the crossmatch for the hospitals and send compatible blood over? If so, it's still sounding like fear - like maybe they are sending the whole sample over on purpose, so they don't even have to mess with it at all. And if their Cheif Tech is there, maybe she/he's telling them to do that????

Read the Serenity Prayer sometimes. It may not help, but it can't hurt!

Hey, if nothing else, think of it as job security for Reference Techs! :cool:

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Hi Hi-Freq,

Yes, that's exactly what we have to do. Say it is an anti-Fya, instead of sending over the required number of Fy(a-) units for them to cross-match, we have to perform the cross-match and then send over the blood.

I wouldn't mind, but part of the remit of Red Cell Immunohaematology is education, and part of that education is to allow people to cross-match blood if they are frightened. The point is, if they do the cross-match and then come back to us and say they cannot get compatible blood; fair enough. We'll then gladly do the cross-match for them. It's when they don't make the effort in the first place.

Call me cynical if you like, but the vast majority of our 50 odd hospitals will do the cross-match, no problem at all, if we send over antigen negative blood (even if there are multiple antibodies).

The majority, if not the vast majority, of our hospitals will perform an "immediate spin" cross-match on a patient with WAIHA if, after alloadsorption, we inform them that there are no detectable underlying atypical alloantibodies and, in an even smaller number of cases, will accept antigen negative blood for an "immediate spin" cross-match, after we've done the serological work-up.

A minority, however, will expect us to do the lot, and it is usually the same hospitals (and it is the "usual suspects", if you know what I mean).

Anyway, you are quite correct. I should stop moaning. I have a mortgage to pay!!!!!!!!!!!!!!!

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How about discussing it with them directly- report it as a complaint to be logged in their deviation system .....it may be their chief doesn't know?

Anyway- this is distracting from my Poll !!...would you test discrepancies on each of your analysers occassionally as a consistancy check ? i'm only mentioning this because I am still having these problems, one analyser detects the -K , -E etc.. , the other one doesn't. ...occassionally. Washer changed, camera changed, PBS stored correctly etc....aaargh!!!!

Edited by RR1
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Surely we should be able to talk to our colleagues openly if we have concerns about things. All this

about the customer is always right- is a load of humbug! How can we improve the way we do things unless we know its possibly causing problems? It doesn't have to be mentioned as a criticism...but in the spirit of continuing education.

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I couldn't agree more (which was why I had my tongue in my cheek) but I can assure you that some (not mentioning any names, but I know you know them Rashmi) always take the slightest thing as criticism (which was why I said it through gritted teeth) and would complain through Clientele (which, for those of you not familiar with this computer programme, is a way of making comments [good or bad] to the NBS, and we then have to spend hours justifying why we said or did what we said or did - and the really high up bosses see this!).

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How about discussing it with them directly- report it as a complaint to be logged in their deviation system .....it may be their chief doesn't know?

Anyway- this is distracting from my Poll !!...would you test discrepancies on each of your analysers occassionally as a consistancy check ? i'm only mentioning this because I am still having these problems, one analyser detects the -K , -E etc.. , the other one doesn't. ...occassionally. Washer changed, camera changed, PBS stored correctly etc....aaargh!!!!

Do you experience the problems (missing reactions) on the same analyzer? If so, it sounds like a problem with one of your instruments. Possibly an internal centrifuge error, or temperature error? If one instrument is missing a -K or -E, I would definitely consult the manufacturer by placing a service call immediately.

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Currently problem is with one analyser, company spent 2 days last week replacing washer, camera - so started detecting the anti-E, but this week stopped detecting the -K on old screening assay.

Checked a new screening assay that was also loaded last week- this detects the anti-K....but I need to validate it !! Also still need to assess all the detection problems for both analysers during last 16 months.

In 16 mths we have had to perform 6 validations on these analysers due to encountered problems or new software installed.Performing one validation is time consuming enough......seriously getting fed up.

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I can definitely see why you are getting fed up. That's way too much work. Can't see any time/cost savings there. Which analyzers are you using? Six validations in 16 months in outrageous - I'd be seriously complaining to the manufacturer/ sales rep for some sort of assistance.

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Another meeting with them next week, they are very nice and try to be helpful....we have just all lost confidence in solid phase, particularly with one of the analysers, and yes, the cost has been enormous.

However, the positive side is I have learnt an awful lot about validating analysers, but trying to keep on top of the papework is interesting.

Have to laugh about it ...or i'll cry!

Thanks for the comment Malcolm- you're right I will !!!!

Actually Hi-Freq- that's a good idea!

Edited by RR1
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