FDA prohibits sampling and testing with the goal of achieving a specific result or to
overcome an unacceptable result (e.g., testing different samples until the desired passing
result is obtained). This practice, also referred to as testing into compliance, is not
consistent with CGMP (see the guidance for industry Investigating Out-of-Specification
(OOS) Test Results for Pharmaceutical Production). In some situations, use of actual
samples to perform system suitability testing has been used as a means of testing into
compliance. We would consider it a violative practice to use an actual sample in test,
prep, or equilibration runs as a means of disguising testing into compliance.
According to the United States Pharmacopeia (USP), system suitability tests should
include replicate injections of a standard preparation or other standard solutions to
determine if requirements for precision are satisfied (see USP General Chapter <621>
Chromatography). System suitability tests, including the identity of the preparation to be
injected and the rationale for its selection, should be performed according to the firm’s
established written procedures and the approved application or applicable compendial
monograph (§§ 211.160 and 212.60).
If an actual sample is to be used for system suitability testing, it should be a properly
characterized secondary standard, written procedures should be established and followed,
and the sample should be from a different batch than the sample(s) being tested (§§
211.160, 211.165, and 212.60). All data should be included in the record that is retained
and subject to review unless there is documented scientific justification for its exclusion.