exlimey

It must be a very interesting policy/procedure that allows falsification of information.

Agreed. It is very easy to fall down the "What if?" rabbit hole and get lost in the details. Complicated systems lend themselves to failures and unofficial shortcuts. The various regulatory agencies were supposed to be incorporating a risk-based approach to their inspections. One could argue that it worked for a while, but now in the absence of big issues, the inspectors are back to the minutiae.

Since anti-A1 lectin is used to differentiate between A1 and A2 (plus other weak subgroups), I would think it important to prove that the reagent does that. Question: Do you use group O cells as the negative control for anti-A and/or anti-B ?

Are you talking about "vacuum" blood collection tubes or just regular test tubes ?

Just to clarify......you have "validated" test tubes ? What was involved ?

I don't know if/how silica might affect testing, but I think that might only apply to the stopper, not the tube proper. You could certainly use regular 16 x 100mm (borosilicate) tubes, rather than the "vacuum" versions. We get generic tubes from VWR, cat # 47729-576.

An excellent question. In theory, there is no such thing as "too cold" for a freezer, so the low temp. alarm setting seems to be pointless. However, if such a unit does activate a low temp. alarm, it may indicate that the unit is malfunctioning in some way. It might just give you time to intervene before the unit goes "bang". I hope I've sufficiently emphasized the low probabilities of the above happening. Our facility still checks the low alarm points for our walk-in freezers (-20 C). Luckily, we have access to liquid nitrogen (LN2) which is very convenient and quick. In the past, we've very awkwardly used a sludge of alcohol and dry-ice to get a very low temperature (-60 C), but this doesn't help with ultra-colds (-80 C). For physical science reasons, we are unable to activate the low alarm on our liquid nitrogen tank !!!! We actually had an inspector challenge us on this issue a number of years ago.

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The Rh typing reagents are designed to react that way. These days, the reagents are monoclonal, IgM in nature and give direct agglutination in a very short amount of time (similar to anti-A and other ABO reagents). Centrifugation is also usually part of the process. Antibodies to Rh antigens in patients (or donors) are typically IgG and require incubation and an antiglobulin phase. Most manual tube testing systems these days also use a potentiator to enhance reactivity and/or reduce incubation times. In the "bad-old-days", Rh typing reagents were human-source, IgG in nature and usually required incubation and an antiglobulin phase.

I like that ! None of this wishy-washy, barely reactive stuff.

I agree with Malcolm. In theory, there may be examples of anti-K that only react with K+k- cells, but in practice it's a very rare event. One of my former colleagues/mentors once said that one shouldn't worry about missing a weak antibody. If the patient were unfortunate to be transfused antigen-positive blood, the former weak antibody would be super-strong next time around !!! Problem solved.

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It sounds as if the "real", actionable result is the 24-hour reading - this should be recorded in the medical files. The "quick-and-dirty" initial test, while not very sensitive, may still be useful in some cases of extreme contamination. It may give the physicians a leg up on treatment. Perhaps a two-field record could be designed? Test #1 = Immediate; Test #2: 24-hr. The interpretation algorithm would include both results.

It's probably all tangled-up in training, competency and proficiency. Maybe an administrative nightmare?

Yeah, I know. I was just being silly, pointing out that sometimes what sounds like a reasonable idea is often impractical and mostly useless. Proposed new policy: Type them once every week for the duration.

Very good point. One could argue that ALL pregnant women should be phenotyped specifically to look for mixed fields.

Concur.

I'm assuming....yes, that gets me into trouble all the time......that you're worried about antigen suppression in pregnant women? Antisera licensed in the USA should have been tested extensively with samples from such patients. If they were unable to correctly phenotype samples from pregnant women, it's unlikely that they would have been approved. As Malcolm points out, the only real troublemakers are the Lewis antigens.

Eek ! I don't like the sound of that. Ethylene oxide (ETO) is a gas used to sterilize materials that can't tolerate other processes (heat/radiation).

I'm certainly not a regulatory expert, but if it is indeed a requirement, I would think that a general "other antigen typing" proficiency would cover you. I can't imagine why one would need proficiency testing for one, or each, typing antiserum.

That was the formaldehyde solution that was used to sterilize reusable dialysis machines in situ. The patients would often make an anti-N-like antibody ("N") that could cause trouble in the AbScr and XM. In the old days, dialysis patients used a LOT of blood. Now, with EPO, they hardly use any. Technically, they didn't have an allergy to the plastics/materials, but rather, as you pointed out, the sterilizing agent. However, it would not surprise me if some patients do develop allergies to today's materials. It seems that everyone is allergic to everything, these days.

Just wondering......several contributors have used the term "direct observation". What would be involved in "indirect observation" ?? Mirrors ? Peripheral vision ? CCTV ?

Fair enough. I thought you meant actual duplicate testing.