{"data":{"id":"us/42-cfr-493.1281","jurisdiction":"us","citation":"42 CFR 493.1281","heading":"Standard: Comparison of test results.","body":"(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.\n(b) The laboratory must have a system to identify and assess patient test results that appear inconsistent with the following relevant criteria, when available:\n(1) Patient age.\n(2) Sex.\n(3) Diagnosis or pertinent clinical data.\n(4) Distribution of patient test results.\n(5) Relationship with other test parameters.\n(c) The laboratory must document all test result comparison activities.","path":["Title 42—Public Health","CHAPTER IV—CENTERS FOR MEDICARE \u0026 MEDICAID SERVICES, DEPARTMENT OF HEALTH AND HUMAN SERVICES","SUBCHAPTER G—STANDARDS AND CERTIFICATION","PART 493—LABORATORY REQUIREMENTS","Subpart K—Quality System for Nonwaived Testing"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-42.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:11Z","sha256":"52a5760c1187dc23f2276cac1126b6489f5eece5a5572c089c563fa73601becc","source_id":"us-cfr","stale":true,"prev":"us/42-cfr-493.1278","next":"us/42-cfr-493.1282"},"notice":"GroundRules: Original legal text. Not legal advice."}