{"uid":"cap_FAljCnpsqDKKzf0mAA4vS","slug":"apri-calculator-ast-to-platelet-ratio-index-13e62d99","name":"APRI Calculator (AST-to-Platelet Ratio Index)","description":"Wai 2003 AST to platelet ratio index (APRI) from AST, laboratory AST ULN, and platelet count. Returns APRI to two decimals plus published training-set cut-offs for significant fibrosis (Ishak ≥3) and cirrhosis. ULN is required; magent does not assume 40 U/L. Not a diagnosis, not FIB-4, and not a biopsy.","url":"https://api.magentlab.com/api/calc/apri","method":"GET","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method"],"properties":{"type":{"type":"string","const":"http"},"method":{"enum":["GET","HEAD","DELETE"],"type":"string"},"headers":{"type":"object","additionalProperties":{"type":"string"}},"queryParams":{"type":"object","required":["ast_u_l","ast_uln_u_l","platelets_10e9_l"],"properties":{"ast_u_l":{"type":"number","description":"Aspartate aminotransferase in U/L (1-10000)."},"ast_uln_u_l":{"type":"number","description":"Laboratory AST upper limit of normal in U/L (5-200). Required; magent does not assume 40."},"platelets_10e9_l":{"type":"number","description":"Platelet count in 10^9/L (1-2000)."}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":{"type":"json","example":{"path":"/api/calc/apri","count":2,"items":[{"apri":1.67,"ast_u_l":90,"formula":"apri","citation":{"id":"wai-2003","doi":"10.1053/jhep.2003.50346","title":"A simple noninvasive index can predict both significant fibrosis and cirrhosis in patients with chronic hepatitis C","source":"Hepatology. 2003;38(2):518-526","authors":"Wai CT, Greenson JK, Fontana RJ, et al."},"disclaimer":"Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.","ast_uln_u_l":45,"platelets_10e9_l":120,"wai_fibrosis_band":"high","formula_expression":"APRI = ((AST / AST_ULN) / platelet_count_10e9_L) * 100","wai_cirrhosis_band":"indeterminate"},{"apri":1.67,"ast_u_l":90,"formula":"apri","citation":{"id":"wai-2003","doi":"10.1053/jhep.2003.50346","title":"A simple noninvasive index can predict both significant fibrosis and cirrhosis in patients with chronic hepatitis C","source":"Hepatology. 2003;38(2):518-526","authors":"Wai CT, Greenson JK, Fontana RJ, et al."},"disclaimer":"Not a medical device. Deterministic published-formula or published-code output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.","ast_uln_u_l":45,"platelets_10e9_l":120,"wai_fibrosis_band":"high","formula_expression":"APRI = ((AST / AST_ULN) / platelet_count_10e9_L) * 100","wai_cirrhosis_band":"indeterminate"}]}},"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.005","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.005/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.005","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.005","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_UK9GQD_o0REgyFbYb-5kL","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.005","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Calculates the Wai 2003 AST-to-Platelet Ratio Index (APRI) from AST, lab-specific AST ULN, and platelet count, returning the score plus published cut-offs for significant fibrosis and cirrhosis.","exampleAgentPrompt":"Calculate the APRI score for a patient with an AST of 72 U/L, a lab ULN of 35 U/L, and a platelet count of 110 × 10⁹/L — and tell me whether the result crosses the published cut-offs for significant fibrosis or cirrhosis.","exampleUseCases":[{"title":"Hepatitis C fibrosis staging support","prompt":"My hepatitis C patient has an AST of 95 U/L, the lab ULN here is 40 U/L, and platelets are 130 × 10⁹/L. What's their APRI score and does it suggest significant fibrosis or cirrhosis?"},{"title":"Non-alcoholic fatty liver disease monitoring","prompt":"I'm tracking a NAFLD patient over time — today's AST is 58 U/L, our institution's ULN is 35 U/L, and platelets are 210 × 10⁹/L. Compute the APRI so I can compare it to last quarter's result."},{"title":"Pre-treatment cirrhosis risk triage","prompt":"Before starting antiviral therapy, I need a quick APRI on this patient: AST 140 U/L, the lab's ULN is 45 U/L, platelets 88 × 10⁹/L. Flag if it hits the cirrhosis threshold."}],"resultDescription":"Returns the APRI score rounded to two decimal places, along with the Wai 2003 published training-set cut-offs for significant fibrosis (Ishak ≥3) and cirrhosis, and an indication of whether the patient's score meets or exceeds those thresholds. Does not return a clinical diagnosis.","failureModes":["Missing required parameter (ast_u_l, ast_uln_u_l, or platelets_10e9_l) returns a 400-level error","Values outside accepted ranges (e.g. platelets <1 or >2000, AST ULN <5 or >200) may be rejected or return a validation error","Payment failure (x402) if USDC balance is insufficient","Network timeout on slow connections"],"whenToPreferThis":"Use this endpoint when you need a fast, formula-based APRI calculation that correctly uses the caller-supplied lab ULN rather than assuming 40 U/L — critical when integrating with labs that use non-standard reference ranges. Prefer this over FIB-4 when platelet count and AST are available but patient age is not, or when the clinical question is specifically framed around the Wai 2003 APRI cut-offs rather than FIB-4 thresholds.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-15T01:05:08.522Z","isFirstParty":false}