Titration Controls

[KathleenSL]

We recently had a CMS/CLIA inspection for our transfusion service (new CLIA number). The assessor told them that they needed to run positive controls with their Anti-A and Anti-B titration procedure [CFR 493.1256]. Our current isohemagglutinin and prenatal titration procedures do not include a control antibody(s). Do you run controls? If yes, what do you use?

[Malcolm Needs ☆]

Never heard anything so stupid. NEGATIVE controls yes, but positive controls?

If there are no reactions at all, then I might worry, but if this doesn't happen..............

[Eagle Eye]

Never heard anything so stupid. NEGATIVE controls yes, but positive controls?

If there are no reactions at all, then I might worry, but if this doesn't happen..............

Agree with you Malcolm....I always do agree with you

[carolyn swickard]

What could possibly be used as positive controls - some kind of home brew that you just freeze and keep rechecking aliquots of? What functions as a negative control? Showing my ignorance here, but I can't even come up with something for that. And no - we haven't been running controls either on our prenantal titrations - but we do freeze and run prior specimens in parallel with the new specimens. Does that count?

[Malcolm Needs ☆]

Well, for example, as a negative control, we run one tube of group A1 and one of group O when we are titrating an anti-B, when we are running an anti-K titration, we run one tube of K-k+, and so on.

BUT A POSITIVE CONTROL...............???????????????!!!!!!!!!!!! UTTER NONSENSE.

[Bill]

We do the same and have even told inspectors that it is our control to ensure consistant reactivity of the "test system."

What could possibly be used as positive controls - some kind of home brew that you just freeze and keep rechecking aliquots of? What functions as a negative control? Showing my ignorance here, but I can't even come up with something for that. And no - we haven't been running controls either on our prenantal titrations - but we do freeze and run prior specimens in parallel with the new specimens. Does that count?

[KathleenSL]

The specific CFR section cited in our Transfusion Service assessment was 42 CFR 493.1256 (3) (iii):

(3) At least once each day patient specimens are assayed or examined perform the following for -

(iii) Test procedures producing graded or titered results, include a negative control material and

a control material with graded or titered reactivity, respectively.

We also run the previous (base line) sample with our prenatal titers and we could argue that it is the "positive contorl material". We would still be out of compliance for the initial prenatal titer or for the isohemagglutinin titers.

[Malcolm Needs ☆]

The specific CFR section cited in our Transfusion Service assessment was 42 CFR 493.1256 (3) (iii):

(3) At least once each day patient specimens are assayed or examined perform the following for -

(iii) Test procedures producing graded or titered results, include a negative control material and

a control material with graded or titered reactivity, respectively.

We also run the previous (base line) sample with our prenatal titers and we could argue that it is the "positive contorl material". We would still be out of compliance for the initial prenatal titer or for the isohemagglutinin titers.

I agree entirely with running the previous sample with the present sample, but this is, as much as anything, to show that there is no operator bias. However, I agree with you entirely, that this also acts as an internal positive control.

I disagree that you would be out of compliance by not using another positive control, unless you were doing an initial prenatal titre or an isohaemagglutinin titre in isolation. Under such conditions, surely you could (if you must!) run a stored sample at the same time - but I repeat that I think that this is total and utter overkill.

The mere fact that you have identified a specific antibody in the initial sample gives you a positive control. It is then only a question of diluting this plasma in saline, or whatever, and adding specific red cells.