When facilities are cited for the STEP test, what corrective actions by the facility are deemed adequate?
First, if the STEP test fails, the inspector should repeat the test for verification. If the STEP test fails again, the facility will need to respond to FDA or the Certifying State Agency. Any subsequent action by the facility that results in a documented improvement in its processing will be considered an adequate response. The facility may use the process described in Reference Information for Facilities – the STEP Test found elsewhere in the PGHS to determine whether the processing speed has returned to acceptable limits.
The following tests should not be done by the inspector, but are rather the responsibility of the facility.
If adhering to film manufacturer's written recommendations, i.e., known processor, known chemistry, and correct developer temperature, then each of the critical parameters needs to be verified. Usually this will be performed by a technical representative or the medical physicist.
- Accuracy of the developer temperature using an accurate thermometer.
- Accuracy of the development time.
- Correct replenishment rates.
Hybrid Chemistry-Processor System
If the chemistry-processor system consists of a hybrid system (i.e., manufacturer A's processor, manufacturer B's chemistry, and manufacturer C's film), and there is no available film manufacturer guidance addressing this hybrid situation, then manufacturer C's film needs to be sensitometrically equivalent to manufacturer C's film when the film is developed according to manufacturer C's recommended processing condition.
The facility can demonstrate "equivalent film performance" for its chemistry-processing system by comparing sensitometric curves. These curves must be generated with the facility's mammography film developed in the (1) facility's processor, and (2) in a chemistry-processor system known to be operating according to the film manufacturer's specifications. The same sensitometer and densitometer must be used for this comparison. . 21 C.F.R. 900.12(e)(1).
It is critical that the films used to compare the different processors be from the same emulsion batch, not simply the same type of film.