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Beware of using reagent antisera to do your QC. The buffers in the reagents can interact with the buffers in the cells and, if using anything other than tube, the buffers in the support medium. You may get false positive results

We used to do weak D tests with post-partum RhIG workups because we did a full blood type and antibody screen with them to make sure mom was a candidate. (Also, to look for massive FMH that would cause an Rh neg mom to look like a weak D but that was before the Fetal Screen/rosette test was invented.) In those days, weak D pos moms were not RhIG candidates, but they are now. With modern reagents, those who react only at AHG anti-D testing are likely to be partial D VI and more likely to make an anti-D. We would rather not find them and just call them Rh negative from the IS test so we don't do weak D testing routinely on obstetric patients. We all dropped the antibody screen when we started using sensitive techniques like gel that picked up the 28 week RhIG dose at the time of delivery. If the screen was negative, you gave RhIG; if the screen was positive with anti-D (unless it was super strong) you still gave RhIG so why do the test if it won't change the treatment? Now we do weak D tests only if the Fetal Screen is "diffusely positive" to understand if a weak D is causing it. We get surprisingly few of them. Of course we do weak D tests on the babies of Rh neg moms.

Chhibber V et al. Is group A plasma suitable as the first option for emergency release transfusion? Transfusion 2014;54:1751-5. Cooling L. Going from A to B: The safety of incompatible group A plasma for emergency release in trauma and massive transfusion patients. Transfusion 2014;54:1695-1697. Isaak EJ, et al. Challenging dogma-Group A donors as universal plasma in massive transfusion protocols. Immunohematology 2011;27:61-65 (NOTE: Free pdf download of full issue). Mehr CR, Gupta R, von Recklinghausen FM, et al. Balancing risk and benefit: maintenance of a thawed group A plasma inventory for trauma patients requiring massive transfusion. J Trauma Acute Care Surg 2013;74:1425-31. Zielinski MD et al. Emergency use of prethawed group A plasma in trauma patients. J Trauma Acute Care Surg 2013;74:69-75 Some of these are several years old. A quick search will literally provide dozens of articles. It was well publicized @ AABB 2018 and the Blood Bank Guy has a podcast from August 2017 that provides more info.

Plus we should remember the goal of each test. In the case of prenatal Rh typing, identifying the patient who should get RhIG to prevent possibly making anti-D whenever possible is the goal, not generating a binary pos/neg answer. Unfortunately the reagents available aren't perfect for this but we need to be able to defend our decisions to the woman who makes anti-D and never has another healthy pregnancy.

I used to be competent in Hemo/Coag/UA/Serology, but as things got busier and more complicated in Blood Bank, I dropped out.

I've used 9 segments from an Rh neg unit plus 1 segment from an Rh pos unit with about 6-8 drops of anti-D. Let that concoction incubate at 37 C for 15 or 20 minutes. I washed the sample once or twice to remove some of the anti-D, then handed it off to the student. When they followed our SOP, the sample worked just fine. I'm sure you could do something similar w/ different antisera, but I've never tried. I just needed to teach the method, not evaluate for a competency.

PERHAPS weak D was included because a positive weak D would alert you to a possible false positive fetal screen.