(a) If a laboratory performs the same test using different methodologies or instruments, or performs the same test at multiple testing sites, the laboratory must have a system that twice a year evaluates and defines the relationship between test results using the different methodologies, instruments, or testing sites.
(b) The laboratory must have a system to identify and assess patient test results that appear inconsistent with the following relevant criteria, when available:
(1) Patient age.
(3) Diagnosis or pertinent clinical data.
(4) Distribution of patient test results.
(5) Relationship with other test parameters.
(c) The laboratory must document all test result comparison activities.