26 pages. Answers the question asked at most inspections and documented at few, which is how the quality control frequency was decided. A five step method maps the testing process, identifies thirty failure modes across consumables, device, operator, specimen and reporting, establishes which are already controlled, scores the residual risk and derives frequency, control levels, internal check reliance and lockout settings from it. Built on two positions: the interval between controls is the size of the recall, and control detects only failures on the path the control material travels. Includes a full assessment worksheet