TRM.44900 states in the Note section that at least 90% of platelet units tested must have maintained appropriate counts and pH during storage. Our transfusion service collects >400 platelet products each month, many of which are doubles but are only testing 4 units from each instrument type to satisfy this requirement. I know CFR21 340.25 specifies that 4 units must be tested monthly but that number seems very low to me in order to reach the 90% confidence level for >400 units of platelets. Any feedback is appreciated.

4 units or 1% percent whichever is greater. Our center does 400 units in two days or about 4000 a month at the most. We usually submit 3 to 5 units a week for QC.