CD14 and mast cell neoplasm: There are also disease states or known infrequent variants in the population where the assay would be expected to have difficulty, examples being paroxysmal nocturnal hemoglobinuria due to loss of GPI‐linked proteins (CD14, CD16), CD16 polymorphisms on neutrophils (one example seen in the present study), plasma cell neoplasms, and mast cell neoplasms.