Loony

We sometimes find them negative in PEG.  If that or a DTT treated screen is negative, we give units as electronic crossmatched (K matched if DTT used).  Anti-CD38 is not a clinically significant antibody, and we have a negative DTT screen we can turn out which makes the computer happy. 

@Bet'naSBB Thank you. This is what I think our workflow should be as well. I’ll consult with management.

My experience with DARA patients is panagglutination with tube testing, both in LISS and PEG. This may be manufacturer dependent. For a first time patient we need to serologically explain the gel reactivity even if the tube was negative. For subsequent visits negative reactivity in tube would be sufficient. I suggest you discuss with your pathologist to see what they are willing to accept. Other BB have different policies with regards to DARA patients, which I hope will be described.    

We have educated our multiple myeloma specialists to send a type and screen before administering the first dose of a daratumumab (Darzalex).  Our standard operating procedure is to have a panel of three cord blood cells (we have a large OB service) that is a laboratory developed test of sorts.  Cord cells do not express CD38 at interfering levels.
As it turns out we have made more of an issue of this than it warrants.  Patients who have negative antibody screens essentially never develop new antibodies to red cells after being started on daratumumab probably because it potential inhibits B cells function.  Minimal B cell function apparently yields little ability to make antibodies to red cell antigens, which are relatively weak alloantigens, especially when there is no adjuvant or inflammation in the recipient.  That said, a manufacturer is making a soluble CD38  analog that will inhibit the anti-CD38 activity and make testing easier from what I've read.  DTT treatment is also reasonable.  But the good news is that patients on this drug do not make new antibodies. There are literature references to this, and we have probably tested about 500 patients with no new alloantibodies. Mostly non-transfused patients, obviously.