Transiently pink-tinged serum in a patient with multiple myeloma and anemia undergoing lenalidomide treatment

Objectives: While in vitro hemolysis is a preanalytical interferent, in vivo hemolysis is a pathologic process requiring investigation. We present a case of an anemic patient with multiple myeloma undergoing chemotherapy with lenalidomide who had multiple serum samples drawn before and after chemotherapy treatment. Some of these samples showed hemolysis. This triggered further investigations to differentiate the cause of the hemolysis. Methods: Various laboratory tests and additional investigations were necessary to establish the root of the hemolytic process. Results: Multiple laboratory tests and a rigorous review of the samples, time of collection, and laboratory results revealed that only samples collected shortly after lenalidomide administration showed hemolysis. This indicates that the chemotherapeutic agent itself was most likely the proximate cause of the in vivo hemolysis in a non- immune-mediated manner. Conclusions: Upon administration, chemotherapeutic agents, such as lenalidomide, can immediately induce transient hemolysis, which can be visualized as transiently pink-tinged serum samples.