{"uid":"cap_PMh1_g1zS55GQ1qVyXzci","slug":"rox-index-calculator-spo2-fio2-rr-24256016","name":"ROX Index Calculator (SpO2/FiO2/RR)","description":"ROX index as (SpO2 percent / FiO2) / respiratory rate in breaths/min (Roca 2016). Returns the index rounded to two decimals. Not a ventilation order. This is not the PaO2/FiO2 (P/F) ratio and not RSBI (respiratory rate / tidal volume).","url":"https://api.magentlab.com/api/calc/rox","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":["spo2_percent","fio2","respiratory_rate"],"properties":{"fio2":{"type":"number","description":"Inspired oxygen as a fraction (0.21-1.0), not a percent. Required."},"spo2_percent":{"type":"number","description":"Pulse-oximetry SpO2 as a percent (50-100)."},"respiratory_rate":{"type":"integer","description":"Respiratory rate in breaths/min (integer 4-80)."}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":{"type":"json","example":{"path":"/api/calc/rox","count":2,"items":[{"rox":22.62,"fio2":0.21,"formula":"rox","citation":{"id":"roca-2016","doi":"10.1016/j.jcrc.2016.05.022","title":"Predicting success of high-flow nasal cannula in pneumonia patients with hypoxemic respiratory failure: The utility of the ROX index","source":"J Crit Care. 2016;35:200-205","authors":"Roca O, Messika J, Caralt B, García-de-Acilu M, Sztrymf B, Ricard JD, Masclans JR"},"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.","spo2_percent":95,"respiratory_rate":20,"formula_expression":"rox = (spo2_percent / fio2) / respiratory_rate"},{"rox":22.62,"fio2":0.21,"formula":"rox","citation":{"id":"roca-2016","doi":"10.1016/j.jcrc.2016.05.022","title":"Predicting success of high-flow nasal cannula in pneumonia patients with hypoxemic respiratory failure: The utility of the ROX index","source":"J Crit Care. 2016;35:200-205","authors":"Roca O, Messika J, Caralt B, García-de-Acilu M, Sztrymf B, Ricard JD, Masclans JR"},"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.","spo2_percent":95,"respiratory_rate":20,"formula_expression":"rox = (spo2_percent / fio2) / respiratory_rate"}]}},"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_-dBJaWNRoZvqkb-N7Q19z","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 ROX index as (SpO2% / FiO2) / respiratory rate per the Roca 2016 definition, returning the result rounded to two decimals.","exampleAgentPrompt":"Calculate the ROX index for a patient with SpO2 of 94%, on 50% inspired oxygen (FiO2 0.50), and a respiratory rate of 30 breaths per minute.","exampleUseCases":[{"title":"HFNC failure risk screening in ICU","prompt":"My patient is on high-flow nasal cannula with SpO2 of 92%, FiO2 of 0.6, and breathing at 35 breaths per minute — what's their ROX index?"},{"title":"Serial ROX monitoring over a shift","prompt":"Track whether this patient is improving: their SpO2 is now 97%, FiO2 has been weaned to 0.35, and respiratory rate is 22 — compute the current ROX index."},{"title":"Respiratory triage in ED for COVID patient","prompt":"For a COVID patient in the ED with SpO2 95% on 40% oxygen (FiO2 0.40) and respiratory rate of 28, calculate their ROX index so I can assess intubation risk."}],"resultDescription":"A single numeric ROX index value rounded to two decimal places, computed as (SpO2_percent / FiO2) / respiratory_rate. No interpretation, diagnosis, or ventilation order is included — the index alone is returned.","failureModes":["Missing required parameter (spo2_percent, fio2, or respiratory_rate) returns a validation error","FiO2 provided as percent (e.g. 40) instead of fraction (0.40) will produce a nonsensical result — no server-side correction","Respiratory rate of 0 causes division-by-zero error","SpO2 or FiO2 outside valid physiological range may be rejected or return unexpected output","Payment not included or insufficient (x402) results in 402 Payment Required response"],"whenToPreferThis":"Use this endpoint when you need the Roca 2016 ROX index specifically — (SpO2/FiO2)/RR — distinct from the PaO2/FiO2 (P/F) ratio or RSBI (RR/tidal volume). Ideal for assessing HFNC success likelihood in clinical decision support agents or ICU monitoring workflows. Prefer this over manual calculation when integrating ROX scoring into automated pipelines.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-15T01:17:30.544Z","isFirstParty":false}