# POSSUM Surgical Risk Calculator (Copeland 1991) > POSSUM Surgical Risk Calculator (Copeland 1991) is a paid API for AI agents from api.magentlab.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-15). Computes Copeland 1991 POSSUM physiologic and operative scores, then returns estimated morbidity and mortality percentages from the unrounded logit equations. ## Facts - Endpoint: GET https://api.magentlab.com/api/calc/possum - Price: $0.005/call - Payment: x402 - Status: unknown - Last checked: 2026-09-15 - Activations on Zero: 0 - Tags: x402 - Canonical page: https://www.zero.xyz/c/possum-surgical-risk-calculator-copeland-1991-329253dd - Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_JGNUczM5Xy4hvPUdWwAkI Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently. ## How to call it through Zero Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`): ```sh zero fetch --capability possum-surgical-risk-calculator-copeland-1991-329253dd ``` Example prompt: Run a POSSUM surgical risk calculation for a 72-year-old patient with no cardiac failure, mild COPD, systolic BP 130, pulse 88, GCS 15, hemoglobin 11.2 g/dL, WBC 9.4, urea 7.1 mmol/L, sodium 138, potassium 4.1, ECG normal, major operative severity, no multiple procedures, blood loss under 100 mL, no peritoneal soiling, benign malignancy status, and elective surgery — what are the physiologic score, operative score, and estimated morbidity and mortality? ## When to prefer this Use this endpoint when you need the original Copeland 1991 POSSUM formulation — specifically when the caller has already assigned the discretized physiologic and operative item values and wants the unrounded logit-based morbidity and mortality estimates. Prefer this over P-POSSUM (Whiteley) when the standard POSSUM mortality equation (not the Portsmouth modification) is required for audit benchmarking or research replication against the original 1991 paper. Do not use for pediatric patients, purely diagnostic questions, or as a substitute for clinical evaluation. ## Known failure modes - Missing required query parameters returns a 400 error - Out-of-range numeric values (e.g. GCS outside 3-15, pulse outside 20-250) may return validation errors - Invalid enum strings for categorical fields (cardiac, ecg, operative_severity, etc.) cause request rejection - Payment failure or insufficient USDC balance results in 402 response - Extreme physiologic values may produce logit-derived probabilities approaching 0% or 100% but remain mathematically valid ## How this service works Copeland 1991 POSSUM surgical audit: 12 physiologic and 6 operative 1/2/4/8 items (age has no 8; ECG has no 2). Returns physiologic_score, operative_score, and estimated morbidity and mortality percents from the unrounded Copeland logits. Not P-POSSUM (Whiteley), not a diagnosis, not operative consent. magent does not examine the patient. ## Output Returns a JSON object with physiologic_score (integer sum of 12 physiologic items, each 1/2/4/8), operative_score (integer sum of 6 operative items), estimated_morbidity_percent (floating-point percent derived from the unrounded Copeland logit), and estimated_mortality_percent (floating-point percent from the Copeland logit). These are statistical estimates from the 1991 Copeland derivation dataset, not clinical diagnoses or consent documents. ## Request schema (JSON Schema) ```json { "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": [ "age_years", "cardiac", "respiratory", "systolic_bp_mm_hg", "pulse", "gcs", "hemoglobin_g_dl", "wbc_k_ul", "urea_mmol_l", "sodium_mmol_l", "potassium_mmol_l", "ecg", "operative_severity", "multiple_procedures", "blood_loss_ml", "peritoneal_soiling", "malignancy", "mode_of_surgery" ], "properties": { "ecg": { "enum": [ "normal", "atrial_fibrillation_60_90", "other_abnormal_or_ectopics_or_q_st_t" ], "type": "string", "description": "Copeland 1991 electrocardiogram as assigned by the caller: normal (1); atrial_fibrillation_60_90 (4); other_abnormal_or_ectopics_or_q_st_t (8). No 2-point cell. magent does not interpret a tracing." }, "gcs": { "type": "integer", "description": "Glasgow Coma Scale total as assigned by the caller, integer 3-15. 15 → 1; 12-14 → 2; 9-11 → 4; ≤8 → 8. magent does not examine the patient." }, "pulse": { "type": "integer", "description": "Pulse in beats/min, integer 20-250. 50-80 → 1; 81-100 → 2; 40-49 or 101-120 → 4; ≤39 or ≥121 → 8. magent does not measure pulse." }, "cardiac": { "enum": [ "no_failure", "diuretic_digoxin_antianginal_or_hypertensive", "peripheral_edema_warfarin_or_borderline_cardiomegaly", "raised_jvp_or_cardiomegaly" ], "type": "string", "description": "Copeland 1991 cardiac signs as assigned by the caller: no_failure (1); diuretic_digoxin_antianginal_or_hypertensive (2); peripheral_edema_warfarin_or_borderline_cardiomegaly (4); raised_jvp_or_cardiomegaly (8). magent does not examine the patient." }, "wbc_k_ul": { "type": "number", "description": "White cell count in ×10^9/L (0.1-100). 4.0-10.0 → 1; 10.1-20.0 or 3.1-3.9 → 2; ≥20.1 → 4; … (truncated) ``` ## More - Live health (JSON, refreshed every minute): https://www.zero.xyz/c/possum-surgical-risk-calculator-copeland-1991-329253dd/health.json - [Zero catalog index](https://www.zero.xyz/llms.txt) - [Other services from api.magentlab.com](https://www.zero.xyz/host/api.magentlab.com/llms.txt)