ABSTRACT: Leukocyte‐depleted components are being used more frequently. Quantitation of residual WBCs is needed for quality control and for establishing the critical level required to prevent alloimmunization. Electronic counting is not accurate at WBC levels below 100/μL (1) and previously proposed techniques are either tedious or require sophisticated equipment. We describe a simple hemacytometer procedure using Türks solution that gives 87–93% recovery at WBC levels below 40/μL.