Defects and countermeasures in laboratory diagnosis of rare IgE multiple myeloma

•IgE multiple myeloma is a rare subtype of MM that is easily misdiagnosed or missed diagnosis.•Application of the SLiM-CRAB criteria to screen high-risk SMM patients could achieve good therapeutic effect.•The lytic bands produced by high macromolecule aggregation in IF are easily misdiagnosed as false negatives.