Centrifuge calibration: optimal spin time

[tbostock]

The procedure for centrifuge calibration, Method 7.5 in the Technical Manual:

We do this annually, and I have a question. There are the saline instructions, as well as high-protein, and Coombs/cellwashing phases. My question: we don't use albumin here, we have gel. So we do our blood typing in tube, and we use gel for antibody screens and panels. Do we still need to calibrate the centrifuge using the albumin? Or is it OK to just do the saline and Coombs/cellwashing phases?

Thanks.

[Lcsmrz]

Doing Spin Cals is an awful, time-consuming process. I would not do more than you have to: if you will never use Albumin, don't calibrate your centrifuges for it.

[kslaforce]

I agree with Lcsmrs - if you don't do the albumin phase, there is no need to calibrate for it. We are like you - we do antibody screens and panels in gel and only use the centrifuge for types so we only calibrate for saline and wash/AHG for the occasional patient that has a history of gel dependent autoantibodies.

[webersl]

We do screens in gel and types in tubes. I do what kslaforce does.

[NedB]

No; you must do the albumin calibration also. The albumin phase also represents your PreWarm screens, panels and crossmatches as well as tube tests to resolve problems, such as taking reverse typing to AHG when testing Patients with out-of-type bone marrow transplanting. The latter can be done with gel but not the PreWarms. The point is, if you use LISS or PeG, you should do the albumin calibration.

[webersl]

NedB,

My understanding is that the reason you do more than one calibration set is because of the difference in VISCOSITY of the reagents - Albumin (22%) is significantly different in viscosity from saline, therefore if you use albumin or high protein anti-D, then you DO need to do an albumin calibration. But LISS is not significantly different in viscosity from saline, and therefore wouldn't need it's own calibration. PeG is irrelevant because you are not centrifuging for agglutination with PeG in the tube - you've washed the PeG away. You are actually centrifuging with AHG, which again (at least for us) is not of a viscosity significantly different than saline. What do I use my serofuge for? Test systems with a viscocity not significantly different from saline, and washing. Washing would be a separate calibration because of the huge difference in saline volume...

So, that's why we just do the saline style cal, and a wash cal. What are your thoughts on that line of logic?

[David Saikin]

If you don't use any high protein reagents, you don't need to validate spin times for them. Your serofuge only needs to be calibrated upon receipt and after "major repairs". If your cell buttons remain consistent and resuspension is not a problem, you are not required to perform this calibration except as indicated above. You are required to check the rpms "periodically".

[NedB]

We do the albumin calibration, partly because we always have. Since centrifuges have gotten so consistent, and we have our spin times down to 7 to 10 seconds versus the 15 to 20 we used to see, we probably don't need to do all three phases anymore. But the thinking here seems flawed. Yes, we spin in LISS and don't spin with PeG, but in each of these we have serum (or plasma) - that's what the albumin represents. By keeping LISS and PeG I infer you are doing some tube testing with serum (7-10% protein) like the albumin in the calibration. You need to do saline phase because this represents ABO and Rh reagent testing. You obviously need to do AHG phase. But the check that has creeped up on us is the washing. One of two serofuges bought at the same time is now showing poor washing at the earlier determined time of 30 seconds. We now must use 45 seconds. I will replace both serofuges and will check my wash times more frequently in the future.

[tbostock]

Alas, I live in NY State, which requires it to be done annually as well as initially and after repair. New Hampshire is starting to look really good....

[crldehart]

I found this discussion while searching for a reference to cite requiring that optimum spin times be performed semiannually. I could not locate a requirement in the CAP Transfusion Medicine Checklist. (Speed & timers are required, but functional calibration is not mentioned). I also could not locate the requirement in the standards.

Does anyone have a source/reference for the specific requirement of performing functional calibration, "spin times" for serological centrifuges? Thanks.

The procedure for centrifuge calibration, Method 7.5 in the Technical Manual:

We do this annually, and I have a question. There are the saline instructions, as well as high-protein, and Coombs/cellwashing phases. My question: we don't use albumin here, we have gel. So we do our blood typing in tube, and we use gel for antibody screens and panels. Do we still need to calibrate the centrifuge using the albumin? Or is it OK to just do the saline and Coombs/cellwashing phases?

Thanks.

[L106]

crldehart - AABB Technical Manual, 16th edition, 2008, Page 980, states:

"Each centrifuge should be calibrated upon receipt, after adjustments or repairs, and periodically. Calibration evaluates the behavior of red cells in solutions of different viscosities, not the reactivity of different antibodies."

[khalidm3]

It is not a mandatory requirement, it is required to meet the requirement of equipment calibration. Inspector's ask about these things and they check the logs. We have time to time visits from WHO/Local authorities/consultancies to improve our centres, and these people ask such work. I do not mean this particular albumin calibration, I wrote it generally. We try to complete all that is mentioned in QC Manual from AABB. I have an old edition, shall get latest soon.

[Eagle Eye]

Technical manual gives guide line it is not a requirement. As long as we follow manuf. requirement we should be OK.

crldehart - AABB Technical Manual, 16th edition, 2008, Page 980, states:

"Each centrifuge should be calibrated upon receipt, after adjustments or repairs, and periodically. Calibration evaluates the behavior of red cells in solutions of different viscosities, not the reactivity of different antibodies."

[LisaZ]

We use gel for blood typing and antibody screens and antibody IDs but perform tube crossmatches, and tube method is our backup. If we use saline for our centrifuge calibrations, is this enough?

[David Saikin]

2 hours ago, LisaZ said:

We use gel for blood typing and antibody screens and antibody IDs but perform tube crossmatches, and tube method is our backup. If we use saline for our centrifuge calibrations, is this enough?

I would say you only need to calibrate what you are going to use your centrifuge for.  No high viscosity reagents, no need to calibrate for them (if you don't have them, how are you going to calibrate them?).   I only do saline, wash times, and ahg testing calibrations.