Phenotyping Cells

[Brenda K Hutson]

I am asking this quesiton on behalf of someone else (but then I don't know the answer either).

Manufacturer's Inserts for various rare antisera, specify the age of the specimen that should be used for typing. Someone at this other Hospital was asked to perform a complete phenotype on a specimen that was 40 days old; he did not want to do it because it went against the Manufacturer's Inserts. However, they then responded to him that after all, we type segments from units that are in an anticoagulant, so why not these patient cells that were suspended in Alsevers.

Any thoughts?

Thanks

Brenda Hutson, CLS(ASCP)SBB

[Brenda K Hutson]

Well, I am going to respond to my own question as I looked further at Manufacturer's Inserts. They state specific limitations for specimens, but say that donor units can be tested until expiration. I do see a comment in relation to possible bacterial contamination causing false test results; so perhaps I have answered my own question.

Brenda

[Malcolm Needs ☆]

Well, I am going to respond to my own question as I looked further at Manufacturer's Inserts. They state specific limitations for specimens, but say that donor units can be tested until expiration. I do see a comment in relation to possible bacterial contamination causing false test results; so perhaps I have answered my own question.

Brenda

Well you have, but there is also the difference in the anticoagulant, the preservative, the controlled storage of the unit, compared to that of the sample (often, initially, kept at sub-optimal temperatures for some time after drawing) etc, etc, so the two are not comparable anyway.

[SMW]

I would want additional information. If the sample does not meet manufacturer's testing requirements I would obtain an authorization to deviate from procedure before performing testing. This process would/should include the justification for deviation, e.g., pre-transfusion sample on a patient now presenting with positive antibody screen, positive DAT, evidence of delayed or serologic transfusion reaction, missing person...... I would then perform testing, with controls as appropriate as possible, report results obtained with appropriate disclaimer(s) and evaluate/interpret findings relative to the big picture. Just as all the red cells do not die at midnight on the day of a product's expiration date, all the antigens do not implode at x days and depending on the circumstances, valuable information may be obtained from a 40-day old sample. But then there's the Murphy's Law of Sample Retention........no matter how long you hold your samples, the one you wish you had today is the one that was discarded yesterday.

[Eagle Eye]

I agree with SMW. You always run across cases where you need to do differently then your routine procedure...but I would document the approval from Medical director and would do it using appropriate controls.