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Antibody Titers


KTUCK

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My facility does has a lot of Ob patients that end up having Antibodies. We send Titers out to our reference lab to be done. I was wondering how many of you do these Titers in house and how complicated it might be for me to just get them started at our facility, or would it even be worth it, from a patient care perspective..???

 

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While I agree that parallel testing of a previous sample and a current sample will potentially even-out the intrinsic variation in antigen expression of test cells, I would hope that a well-trained cadre of operators following a good SOP would get the same titration results (end-point) when testing the same sample time after time.

A vague, musty memory suggests to me that there are proficiencies along those lines - independent samples to be titrated, tested and the results reported. Perhaps that has gone the way of the dinosaurs?

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27 minutes ago, exlimey said:

While I agree that parallel testing of a previous sample and a current sample will potentially even-out the intrinsic variation in antigen expression of test cells, I would hope that a well-trained cadre of operators following a good SOP would get the same titration results (end-point) when testing the same sample time after time.

A vague, musty memory suggests to me that there are proficiencies along those lines - independent samples to be titrated, tested and the results reported. Perhaps that has gone the way of the dinosaurs?

I agree, BUT, if the antibody identified in the previous sample has, for example, a specificity of anti-E, and you titrate using r"r red cells and get a titre of, for example, 64, and then the next sample gives a titre of 4, what do you do?  At this stage, you have no idea whether the original titre of 64, or this titre of 4, is correct.  It could be that there is a second specificity present (say an anti-Swa) and it just so happened that the original r"r red cells also expressed the Swa antigen.  Now, I will readily admit that both anti-Swa and the antigen Swa are exceedingly rare, so these were probably not a great example, but, supposing it was an anti-E and an anti-Kpa?

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You will have to perform Ab titer surveys. CAP surveys for titers are rather pricey.

Most of the patient results are more of a followup thing - important, but generally not emergent. The vast majority will not need same day turn around, so as long as your reference lab can give you results in a day or 2, that shouldn't be a problem. All titers we did or that we send out are done in parallel with the previous specimen, if sufficient specimen is available. Malcolm has given a great explanation as to why that is important. We stopped doing titers several years ago. We had plenty of work without bogging down our day with titers, the surveys were expensive, the reference charge was/is reasonable - doing them just wasn't worth it. If we need results quickly, we have the option of requesting them STAT. No complaints from physicians about our turn around times. Our OB docs order titers on their patients at each monthly visit unless the titer skyrockets - at that point they stop the titers and refer them to specialists at a major medical center for monitoring.

 

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21 hours ago, Malcolm Needs said:

I agree, BUT, if the antibody identified in the previous sample has, for example, a specificity of anti-E, and you titrate using r"r red cells and get a titre of, for example, 64, and then the next sample gives a titre of 4, what do you do?  At this stage, you have no idea whether the original titre of 64, or this titre of 4, is correct.

A valid position, BUT, how often is such a large discordance seen ? Probably not often. I'm sure there are statistics out in the ether somewhere.

Perhaps storing the previous sample, or series of samples would be useful - this would allow a logical investigation of any anomalous results. Repeating the titration every time is extra work and in most cases, of little value. 

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29 minutes ago, exlimey said:

A valid position, BUT, how often is such a large discordance seen ? Probably not often. I'm sure there are statistics out in the ether somewhere.

Perhaps storing the previous sample, or series of samples would be useful - this would allow a logical investigation of any anomalous results. Repeating the titration every time is extra work and in most cases, of little value. 

You are ABSOLUTELY correct in every aspect exlimey and I have to admit (and this shows me up as a COMPLETE idiot), I had never even thought of only doing the previous titration again if there was such a big difference.  I BOW TO YOUR BETTER LOGIC!!!!!!!!!!!!

I also apologise to all of the staff who have worked under me, who have done countless titrations of previous samples for no logical reason.

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I was always taught that you titer the previous specimen in parallel to help eliminate tech variability.  What you are really looking for is a significant increase in titer from one month to the next.  The previous titer may have been 4 by that tech and 8 by this tech.  The current titer may be 64 if tested by the previous tech and 128 when tested by the current tech.  Either way, that is an increase, regardless of the actual number, and the doc should probably be concerned.

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I was taught that testing titers in parallel with the previous specimen is primarily done so that any change in titer can be objectively compared; you are using the same cell of the same age with both specimens at the same time with the same tech. The secondary reason was to monitor and so minimize tech variability i.e. plus or minus one titer from the last techs results.

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9 minutes ago, Ensis01 said:

I was taught that testing titers in parallel with the previous specimen is primarily done so that any change in titer can be objectively compared; you are using the same cell of the same age with both specimens at the same time with the same tech. The secondary reason was to monitor and so minimize tech variability i.e. plus or minus one titer from the last techs results.

True, but as exlimey said, if there is a difference, you still have the opportunity to defrost the previous sample, titrate it in parallel with the present sample, using the same test cell and the same tech.  What I was doing was asking/ordering my staff to do this every time, even when the results of the present sample were identical to the previous sample - which was over the top.

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11 hours ago, Ensis01 said:

Agreed Malcolm; much more efficient. That being said, if titers are few and far between in the lab testing in parallel may be easier to monitor and review.

 

Agree too Ensis01, although, as a Reference Laboratory, we were doing something like 15 samples a day (30 with the previous samples), so it would have been more sensible not to titre every single one of those in parallel.  If only I had seen the light earlier in my career!

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Just to bring patient variability back into this conversation - we were repeating the antibody ID on a new titer specimen to see if the antibody remained the same (anti-E)  - our current procedure.  This time around the pt also appears to have an anti-Dia too - not always detectable on our current screens and panels.  Testing of the current and previous specimen showed that the anti-Dia was there last time too and was even higher than the anti-E titer (4 for anti-Dia and 1 for anti-E) for both specimens.

Fun with patients every day.

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On ‎1‎/‎5‎/‎2017 at 9:47 AM, KTUCK said:

My facility does has a lot of Ob patients that end up having Antibodies. We send Titers out to our reference lab to be done. I was wondering how many of you do these Titers in house and how complicated it might be for me to just get them started at our facility, or would it even be worth it, from a patient care perspective..???

 

Titers are time consuming as SMILLER stated.  Also, some of my dedicated BB staff had difficulty with titers when we first brought them in.   It did get better but if I had my druthers I would let a reference lab handle them. 

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19 hours ago, cswickard said:

Just to bring patient variability back into this conversation - we were repeating the antibody ID on a new titer specimen to see if the antibody remained the same (anti-E)  - our current procedure.  This time around the pt also appears to have an anti-Dia too - not always detectable on our current screens and panels.  Testing of the current and previous specimen showed that the anti-Dia was there last time too and was even higher than the anti-E titer (4 for anti-Dia and 1 for anti-E) for both specimens.

Fun with patients every day.

You were unlucky tripping over an antibody to a to a low incidence antigen. Sometimes the fancy commercial panels are too fancy. Some of the antibodies to low incidence antigens are quite common and only remain undetected because regular red cell panels do not have the corresponding antigens.

In this situation, I would make every effort the get a blood sample from the putative father - a sometimes awkward and emotionally-charged situation. Test the father for Dia (and E while you're at it) and if negative, you don't have to continue to evaluate the potency of the antibody(ies).

Getting a sample doesn't always work, of course and there's always a risk that the "father" is not THE father.

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  • 3 months later...

Hi All, to add to this antibody discussion a bit further - we test in parallel for reasons above (ie to rule out tech variability - detect a difference in titration which is the most important for the clinician) however, I am curious to know how blood banks titer when there are multiple antibodies present. We have a mom with 3 antibodies showing and one historical not showing and it's proving extremely difficult to separate out the different antigens using our 4 in date panels to do the titer studies. Should we just use one or two cells with the antigens and try to be consistent when the mom comes back in for titers (they are monitoring every 4 weeks right now) or try to divide out as best we can? what do you all recommend?!?! 

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3 hours ago, MeganPLT said:

Hi All, to add to this antibody discussion a bit further - we test in parallel for reasons above (ie to rule out tech variability - detect a difference in titration which is the most important for the clinician) however, I am curious to know how blood banks titer when there are multiple antibodies present. We have a mom with 3 antibodies showing and one historical not showing and it's proving extremely difficult to separate out the different antigens using our 4 in date panels to do the titer studies. Should we just use one or two cells with the antigens and try to be consistent when the mom comes back in for titers (they are monitoring every 4 weeks right now) or try to divide out as best we can? what do you all recommend?!?! 

It would very much depend on the specificity of the antibodies, and their historic (by that, I mean overall, not the history of this lady's previous pregnancies) ability to cause clinically significant HDFN.  Unless I know the specificities, I can't really comment.

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