Code of Federal Regulations Title 42. Public Health § 42.493.1281 Standard:  Comparison of test results

(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:

(c) The laboratory must document all test result comparison activities.