{"data":{"id":"us/42-cfr-493.931","jurisdiction":"us","citation":"42 CFR 493.931","heading":"Routine chemistry.","body":"(a) Program content and frequency of challenge. To be approved for proficiency testing for routine chemistry, 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 specimens 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 listed below is five serum, plasma or blood samples.\nTable 1 to Paragraph (b)—Analyte or Test Procedure\nAlanine aminotransferase (ALT/SGPT).\nAlbumin.\nAlkaline phosphatase.\nAmylase.\nAspartate aminotransferase (AST/SGOT).\nBilirubin, total.\nBlood gas (pH, pO2, and pCO2).\nB-natriuretic peptide (BNP).\nproBNP.\nCalcium, total.\nCarbon dioxide.\nChloride.\nCholesterol, total.\nCholesterol, high density lipoprotein.\nCholesterol, low density lipoprotein, (direct measurement).\nCreatine kinase (CK).\nCK-MB isoenzymes.\nCreatinine.\nFerritin.\nGamma glutamyl transferase.\nGlucose (Excluding measurements on devices cleared by FDA for home use).\nHemoglobin A1c.\nIron, total.\nLactate dehydrogenase (LDH).\nMagnesium.\nPhosphorus.\nPotassium.\nProstate specific antigen (PSA), total.\nSodium.\nTotal iron binding capacity (TIBC) (direct measurement).\nTotal Protein.\nTriglycerides.\nTroponin I.\nTroponin T.\nUrea Nitrogen.\nUric Acid.\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 chemistry tests or analytes, the 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 chemistry 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 (SD) 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\nAlanine aminotransferase (ALT/SGPT) Target value ±15% or ±6 U/L (greater).\nAlbumin Target value ±8%.\nAlkaline phosphatase Target value ±20%.\nAmylase Target value ±20%.\nAspartate aminotransferase (AST/SGOT) Target value ±15% or ±6 U/L (greater).\nBilirubin, total Target value ±20% or ±0.4 mg/dL (greater).\nBlood gas pCO2 Target value ±8% or ±5 mm Hg (greater).\nBlood gas pO2 Target value ±15% or ±15 mmHg (greater).\nBlood gas pH Target value ±0.04.\nB-natriuretic peptide (BNP) Target value ±30%.\nPro B-natriuretic peptide (proBNP) Target value ±30%.\nCalcium, total Target value ±1.0 mg/dL.\nCarbon dioxide Target value ±20%.\nChloride Target value ±5%.\nCholesterol, total Target value ±10%.\nCholesterol, high density lipoprotein (HDL) Target value ±20% or ±6 mg/dL (greater).\nCholesterol, low density lipoprotein (LDL), direct measurement Target value ±20%.\nCreatine kinase (CK) Target value ±20%.\nCK-MB isoenzymes Target value ± 25% or ±3 ng/mL (greater) or MB elevated (presence or absence).\nCreatinine Target value ±10% or ±0.2 mg/dL (greater).\nFerritin Target value ±20%.\nGamma glutamyl transferase Target value ±15% or ±5 U/L (greater).\nGlucose (excluding measurements devices cleared by FDA for home use.) Target value ±8% or ±6 mg/dL (greater).\nHemoglobin A1c Target value ±8%.\nIron, total Target value ±15%.\nLactate dehydrogenase (LDH) Target value ±15%.\nMagnesium Target value ±15%.\nPhosphorus Target value ± 10% or ±0.3 mg/dL (greater).\nPotassium Target value ±0.3 mmol/L.\nProstate Specific Antigen, total Target value ±20% or ±0.2 ng/mL (greater).\nSodium Target value ±4 mmol/L.\nTotal Iron Binding Capacity (TIBC). (direct measurement) Target value ±20%.\nTotal Protein Target value ±8%.\nTriglycerides Target value ±15%.\nTroponin I Target value ± 30% or ±0.9 ng/mL (greater).\nTroponin T Target value ±30% or ±0.2 ng/mL (greater).\nUrea nitrogen Target value ±9% or ±2 mg/dL (greater).\nUric acid Target value ±10%.\n(3) The criterion for acceptable performance for qualitative routine chemistry 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":"5f0b5f65313f7e6b0c669ce5c2914d7c052dab54694c833eee548fce0f31f362","source_id":"us-cfr","stale":true,"prev":"us/42-cfr-493.929","next":"us/42-cfr-493.933"},"notice":"GroundRules: Original legal text. Not legal advice."}