sdarmor1

I think your physician's diagnosis is probably correct, as it very much looks like a "warm" auto-antibody, but you will need to ensure that there are no underlying clinically significant atypical alloantibodies.

While I am not an auditor; I would assume that from an auditor's perspective a hospital not being able to show the tracking of how, where, when and why a unit of blood disappeared from the BB inventory would be a bigger problem than verbally taking registration for a patient in transit to a different hospital or trapped in a car. 

Yikes, can't imagine.  We issue about 25k red cells a year.  I have no idea where we'd keep the returns.
We save a segment.

Our only difference was that we cut off 2 segments.  We stopped getting bags back over 25 years ago.  Hated the mess and getting them back served no real purpose.

We don't have bags returned to us.  We take off 2 segments when we retype the units and save for a month, 1 week in each bag.  It's easy to find by when it was retyped in the computer and there are only four small bags to check for the correct date.

We have yet to see a patient on daratumamab who has made an anti-K antibody after years of transfusing red cells without regard to K antigen status.  We use cord red cells in an antibody screen to rule out significant antibodies to allogeneic red cells (they are CD38 negative) as our method of dealing with this issue of pan-reactivity from daratumumab. I know this practice isn't allowed in the UK due to the over the top regulations that followed the infant parts kerfuffle.  We detect plenty of anti-K's, just NOT in patients receiving anti-B cell therapies.  In fact, I cannot recall a single new red cell alloantibody in myeloma or lymphoma patients receiving daratumumaub, rituximab, etc.  No B cells equals dramatically reduced risk of alloimmunization, so you may be worrying about something that is pretty unlikely to happen.  Just another approach.

There is a difference, I believe,  between not being able to rule out an antibody in the context that it may be there, the answer no you state above, and not being able to rule out due to the method limitations (DTT). The DTT method  limitations result in K neg units being given but once the DARA effects wears off a different, more appropriate (and better) method is used so anti-K can be ruled out and the K neg requirement dropped.      

It makes sense to have a K neg policy while the patient is on anti-CD38 therapy, i.e. K neg units are given because DTT meant Kell antibodies could not be ruled out. Once anti-CD38 therapy is finished and if the patient never had anti-K and you can rule it out I see no reason to keep giving K neg units.

We do not unless the patient has Anti-K. Darzalex is just a transient interfering substance. If there is no DTT neutralization required and no antibody detected, it is not necessary. Plus, I don't see how I can charge for the antigen typing in that scenario. I think that risks fraudulent billing.