【Objective】 To explore the challenging blood cross-matching and resolution for multiple myeloma (MM) patients in different disease stages. 【Methods】 For a patient who was first diagnosed as MM and scheduled for blood transfusion, his blood was cross matched with donors’ blood by microcolumn gel method and tube test. When the major side of cross-matching was agglutinated, the patient’s plasma was cross matched with donors’ red blood cell (RBC) by polybrene test, then plasma dilution cross matched with donors’ RBC by microcolumn gel method. For a patient who was diagnosed as recurrent refractory MM and scheduled for blood transfusion, his blood was cross matched with donors’ blood by microcolumn gel method. 【Results】 1) Case 1 was a first-visit outpatient. The major side of microcolumn cross-match test was agglutinated with the shape of fine line. The result of tube method also showed agglutination of major sides, and the rouleaux were detected by the microscopy. Then polybrene method and microcolumn gel method (after plasma diluted) were applied for cross-matching again with the above two donors’ blood and showed compatibility. 2) Case 2 was a recurrent refractory MM patient. The major and minor sides of microcolumn cross-match test were both agglutinated with the shape of granular. The patient was treated with anti-CD38 monoclonal antibody. The RBCs, after treated with dithiothreitol (DTT) was used to cross match with patient plasma by microcolumn test, and the result was compatible. 【Conclusion】 Polybrene method and microcolumn gel method after plasma diluted are suitable for blood cross-matching of newly diagnosed MM patients, also for those treated with CD38 monoclonal antibody, as the drug interference with cross-matching can be eliminated by DTT.