Why is a type and crossmatch needed before starting patients on treatment with daratumumab (Darzalex)?

Daratumumab is a monoclonal antibody used as monotherapy or in combination with other treatments to treat multiple myeloma. The agent is targeted to CD-38, which is also expressed on red blood cells. This can cause erratic false positives in the blood antibody screening and crossmatching performed prior to a transfusion.

Although the patient’s ABO and Rh blood type are not affected, detection of minor antibodies is affected. Due to the long lifespan of red blood cells, the effects of daratumumab on crossmatching can last up to 6 months after completion of therapy.

Specific techniques can be used to complete blood compatibility testing, but these can require additional time. The laboratory performing the crossmatching should also be informed in advance that the patient is on daratumumab to facilitate proper testing. Type and screen of patients prior to starting daratumumab is recommended to prevent delays in transfusion crossmatching. 

See also: Value of Type and Crossmatch Prior to Daratumumab Administration