John Hansen

I just answered this question. My Score PASS  

I just answered this question. My Score FAIL  

My current lab is not accredited by CAP, so I don't know if CAP has changed requirements. In 2024, when I was working at a CAP accredited lab, we would mostly use our calibrations to verify the AMR. We'd keep printouts of calibrations for each analyte to show that the AMR was verified by those calibrators. We had some analytes where the calibrators did not span the full range of the AMR. We'd usually get calibration verification samples from Maine Standards for those. I also had an analyzer that did 2-point calibrations, and the manufacturer had a kit for verifying AMR that we would purchase. For the analytes that needed additional samples, Maine Standards would statistically analyze our results and send those back to us, and the ones I got from the manufacturer, I'd put in Excel and graph them with a best fit line to show me slope, bias, and correlation factor.

You verify linearity by testing a low, mid, and high value along the AMR. What I've seen on the job is a low point needs to be within 50% of the low end of AMR and the high point needs to be within 10% of the high end of AMR. Those requirements are developed by the lab prior to verification, and are up to the pathologist. Many times, calibrators satisfy this requirement if there are 3+ levels of calibrator. However, I've had some calibrators that do not sufficiently cover the AMR. I've either had to use additional samples to verify linearity in those cases, or you can change AMR to fit with what the calibrators can verify.

The titer was 1, which means that none of the dilutions had 1+ activity. The original poster never said what the reactions were. I'm assuming that the reaction on tube one was only 1+, and then it is very possible that further dilutions had +/- activity. The 4+ came from Malcolm theorizing another situation that might give a high score.

It won't tell you there is mixed field. I think the best it would do is flag reactions that are weak, and it won't interpret reactions that don't make sense. It may also depend on facility protocol. We visually examine the pictures of the test wells before accepting results. Also, I was wondering if you are referring to testing ABO/Rh in solid phase or in micro-wells? The Echo tests this with microwells and liquid reagent instead, so it is just like reading a mini-test tube.

I know this post is super old, but I think I know what happened. Maybe this information will still be useful to you. I just learned about titer scores in some continuing education, and then found it in my AABB technical manual in the methods section. You get scores for all positive reactions. Each strength of reaction gets a different score. In my continuing ed from the American Red Cross, they gave the scores as: 4+ is 12, 3+ is 10, 2+ is 8, 1+ is 5, and +/- is 2. The score is measured differently than the titer. The titer is the reciprocal of the highest dilution showing 1+ reactivity, which would be tube one in your case. But the score is measured out all the way to the endpoint. If this patient had 1+ on tube one, but weak reactions out to the 1:8 dilution, it would give you a score of 13 (5+2+2+2+2). Hope that helps in the future.

We run an Echo in our lab. We haven't had problems with it. I haven't had much experience with gel, but I work with techs that have, and they have no complaints with the Echo. The nonspecific reactions I have seen are rare. The only times we waste test strips are when we have very low volumes of patients. In addition, the turn around times seem much better than the Provue. From receipt to result, I routinely have my type and screens done within 35 minutes. If you do larger batches, that would increase to maybe 40-45 minutes. My only complaint would be the way it processes blood types when you do a type and screen. It will start the antibody screen, then it will wait ten minutes or so before starting the blood type. I'm unaware of any issue other than software preventing quicker testing. Still, it has the blood type resulted about 8 minutes before the antibody screen. Our solution is if we want the blood type quickly, we do it by tube. No big deal. I am also pleased with the many tests it can perform. It's saved us a ton of manual work we used to have to do.

We report the screen as positive, do a mini or full panel (up to the technologist) and report that the anti-D is most likely due to RhoGam. I think this is to cover our butts if the anti-D was actually from mom. As far as the computer goes, we have a different result code for RhoGam anti-D, and we will deactivate the antibody as soon as we have a negative screen again.

We do the KB stain in blood bank

My mind was fixated on the antibody screen and didn't fully answer the original question. We also do a D type unless there are two previous types on file.

We used to do an antibody screen at 28 weeks, but that was recently modified. If the patient has had a screen during their pregnancy, it is not done again at 28 weeks unless the doctor orders it. Most of the time, it means we still do it, but there has been two instances where the mom had either been in the ER early in pregnancy, or had a prenatal workup done early on. Didn't sit well with any of us.

I know it can seem insulting when they call you asking if a unit is compatible, but at least it is some reassurance that they are actually looking at the unit's and patient's blood types before transfusion. Not all in blood bank do a good job, and even the ones that know what they are doing can make mistakes.

We use FFP and 24 hour plasma as equivalent. We have moved to thawed plasma with a 5 day outdate. We are using that as equivalent as well (although it is usually used within a 24 hour period anyways).

Don't forget that the minor mismatch is very minor in the case of a neonate, since a neonoate should not have an appreciable titer of A or B antibodies until later in life, and may have little to none of Mom's antibodies