{"data":{"id":"us/42-cfr-493.933","jurisdiction":"us","citation":"42 CFR 493.933","heading":"Endocrinology.","body":"(a) Program content and frequency of challenge. To be approved for proficiency testing for endocrinology, a program must provide a minimum of five samples per testing event. There must be at least three testing events at approximately equal intervals per year. The annual program must provide samples that cover the clinically relevant range of values that would be expected in patient specimens. The samples may be provided through mailed shipments.\n(b) Challenges per testing event. The minimum number of challenges per testing event a program must provide for each analyte or test procedure is five serum, plasma, blood, or urine samples.\nTable 1 to Paragraph (b)—Analyte or Test\nCancer antigen (CA) 125.\nCarcinoembryonic antigen (CEA).\nCortisol.\nEstradiol.\nFolate, serum.\nFollicle stimulating hormone.\nFree thyroxine.\nHuman chorionic gonadotropin (HCG) (excluding urine pregnancy tests done by visual color comparison categorized as waived tests).\nLuteinizing hormone.\nParathyroid hormone.\nProgesterone.\nProlactin.\nTestosterone.\nT3 Uptake.\nTriiodothyronine.\nThyroid-stimulating hormone.\nThyroxine.\nVitamin B12.\n(c) Evaluation of a laboratory's analyte or test performance. HHS approves only those programs that assess the accuracy of a laboratory's responses in accordance with paragraphs (c)(1) through (5) of this section.\n(1) To determine the accuracy of a laboratory's response for qualitative and quantitative endocrinology tests or analytes, a program must compare the laboratory's response for each analyte with the response that reflects agreement of either 80 percent or more of 10 or more referee laboratories or 80 percent or more of all participating laboratories. Both methods must be attempted before the program can choose to not grade a PT sample.\n(2) For quantitative endocrinology tests or analytes, the program must determine the correct response for each analyte by the distance of the response from the target value. After the target value has been established for each response, the appropriateness of the response must be determined by using either fixed criteria based on the percentage difference from the target value or the number of standard deviations (SDs) the response differs from the target value.\nTable 2 to Paragraph (c)(2)-Criteria for Acceptable Performance\nThe criteria for acceptable performance are— Analyte or test Criteria for acceptable performance\nCancer antigen (CA) 125 Target value ±20%.\nCarcinoembryonic antigen (CEA) Target value ±15% or ±1 ng/mL (greater).\nCortisol Target value ±20%.\nEstradiol Target value ±30%.\nFolate, serum Target value ±30% or ±1 ng/mL (greater).\nFollicle stimulating hormone Target value ±18% or ±2 IU/L (greater).\nFree thyroxine Target value or ±15% or ±0.3 ng/dL (greater).\nHuman chorionic Target value ±18% or ±3\ngonadotropin (excluding urine pregnancy tests done by visual color comparison categorized as waived tests) mIU/mL (greater) or positive or negative.\nLuteinizing hormone Target value ±20%.\nParathyroid hormone Target value ±30%.\nProgesterone Target value ±25%.\nProlactin Target value ±20%.\nTestosterone Target value ±30% or ±20 ng/dL (greater).\nT3 uptake Target value ±18%.\nTriiodothyronine Target value ±30%.\nThyroid-stimulating hormone Target value ±20% or ±0.2 mIU/L (greater).\nThyroxine Target value ±20% or ±1.0 mcg/dL (greater).\nVitamin B12 Target value ±25% or ±30 pg/mL (greater).\n(3) The criterion for acceptable performance for qualitative endocrinology tests is positive or negative.\n(4) To determine the analyte testing event score, the number of acceptable analyte responses must be averaged using the following formula:\n(5) To determine the overall testing event score, the number of correct responses for all analytes must be averaged using the following formula:","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 I—Proficiency Testing Programs 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":"369ab9470be74f74ac0db005d23dfe03e79e206f066b88580a3e4c52c2eacad0","source_id":"us-cfr","stale":true,"prev":"us/42-cfr-493.931","next":"us/42-cfr-493.937"},"notice":"GroundRules: Original legal text. Not legal advice."}