I can't think of a single regulatory requirement that says the Anti-D reagent has to be tested against a Weak D positive Cell so this would be subject to local regulations and Medical Director preference. Immucor package insert for Anti-D Series 4 and corQC attached for reference.corQC; 381-6.pdfAnti-D (Series 4) 336-9.pdf
Personally, I like the idea expanding our QC of Anti-D reagent with a cell that is known to be non-reactive at the immediate spin phase and reactive at the IAT phase. But, this is just extra cost and is not required.
Deep Dive Question: Should we be thinking on a more fundamental level with this QC than what some have suggested?
There are two clones of Anti-D in most reagents used for bench testing: an IgM clone and an IgG clone. When testing controls at the immediate spin phase we are verifying the reactivity of the IgM clone. Taking cells through the weak D phase should provide adequate control for the reactivity of the IgG clone. IAT testing should be performed on both positive and negative cells.
Analogous Example:
With Polyspecific AHG reagent there are 2 different clones present: an anti-IgG clone and an anti-complement clone. QC is not accomplished through testing with IgG check cells and a negative control with unsensitized cells, a QC test must be performed for the anti-complement reactivity as well.