Gel vs.Tube Sensitivity and specificity

[cassinnc]

If you have performed studies to correlate the tube and gel methods, did you determine the sensitivity and specificity for the individual methods? If so, how did you perform the calculations? If you did not determine the sensitivity and specificity of the methods, how did you state your conclusion at the end of your correlation studies?

We do not have a transfusion medicine pathologist and I want to make sure my statements are clear in my validation summary.

We are switching from Immucor to Biotest in the tube for back-up, from serum to plasma, and from tube to Gel as our primary test method for antibody screens and identifications. Any help with this is greatly appreciated!

[tbostock]

We just switched from Immucor to Biotest tube reagents last year; here is a section from my validation, hope it's helpful:

To ensure that the new reagents are capable of consistently meeting expectations compared to the reagents in use (Immucor). Because Blood Bank reagents undergo intensive testing by the manufacturer to qualify for FDA licensing, it is not necessary for the end user to repeat this level of testing unless used in a manner that is not consistent with the manufacturer’s instructions. For blood typing reagents 20 samples will be used of various ABO/Rh types. For antibody detection and identification, the specificity and sensitivity of the method will be calculated and compared to the previous method. 20 samples will be used for antibody detection, and 10 samples will be used for antibody identification (varied alloantibodies) at the Horton Campus, and 5 samples for antibody identification at the Arden Hill Campus. The antisera will be tested using known homozygous positive, heterozygous positive and negative cells. See attached sheets for testing results.

Sensitivity = True Pos ÷ (True Pos + False Neg) X 100

Specificity = True Neg ÷ (True Neg + False Pos) X 100

All package inserts will be reviewed and any necessary changes will be made to procedures. Blood Bank techs will be advised of any significant changes as needed.

Expected Outcomes:

ABO/Rh typing reagents: 100% agreement

Antibody detection and identification: at least 95% sensitivity and 95% specificity

Antisera reagents: 100% agreement with at least 1+ reactivity.

[cassinnc]

Thanks Terri! This is the same formula I have with similar sensitivity and specificity expectations.