# Rome IV Functional Constipation (C2) Calculator > Rome IV Functional Constipation (C2) Calculator is a paid API for AI agents from api.magentlab.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14). Evaluates nine caller-assigned boolean criteria to determine whether a patient meets the Rome IV (Mearin 2016) C2 Functional Constipation criteria, returning a true/false result and symptom count. ## Facts - Endpoint: GET https://api.magentlab.com/api/calc/rome_iv_fc - Price: $0.005/call - Payment: x402 - Status: unknown - Last checked: 2026-09-14 - Activations on Zero: 0 - Tags: x402 - Canonical page: https://www.zero.xyz/c/rome-iv-functional-constipation-c2-calculator-6b5c0137 - Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_HDz2z2s8Z9wwytYwjBZxM 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 rome-iv-functional-constipation-c2-calculator-6b5c0137 ``` Example prompt: Check if this patient meets Rome IV functional constipation criteria: symptoms present for the last 3 months with onset 6+ months ago, straining in more than 25% of defecations is true, lumpy or hard stools more than 25% is true, incomplete evacuation more than 25% is true, anorectal obstruction more than 25% is false, manual maneuvers more than 25% is false, fewer than 3 spontaneous bowel movements per week is true, loose stools are rare without laxatives is true, and insufficient criteria for IBS is true. ## When to prefer this Use this endpoint when you need a fast, deterministic, standards-compliant computation of Rome IV C2 Functional Constipation criteria per Mearin 2016, and the caller is responsible for assigning all nine clinical flags from their own assessment. Prefer this over manual rule application when integrating Rome IV FC into EHR workflows, clinical research pipelines, or decision support tools. Do not use for pediatric constipation, opioid-induced constipation, Rome IV IBS criteria, or Manning criteria — separate endpoints or tools apply to those. ## Known failure modes - Missing any of the nine required boolean query parameters returns a validation error - Invalid non-boolean values for boolean fields cause a bad request response - Payment failure or missing x402 payment header results in a 402 Payment Required response - All nine flags provided but logic edge cases (e.g. symptom_count >= 2 but other criteria not met) correctly returns rome_iv_fc = false ## How this service works Mearin 2016 Rome IV C2 FC. rome_iv_fc is true iff last-3-months criteria with 6-month onset, at least 2 of 6 symptoms (straining, lumpy/hard stools, incomplete evacuation, anorectal obstruction, manual maneuvers, fewer than 3 SBM/week), loose stools rare without laxatives, and insufficient IBS criteria. symptom_count is 0-6. Caller assigns nine flags. magent does not examine the patient. Not a diagnosis, not Rome IV IBS, not Manning, not opioid-induced or child constipation. ## Output Returns a boolean rome_iv_fc indicating whether the patient meets Rome IV C2 Functional Constipation criteria (true/false), and an integer symptom_count from 0 to 6 representing how many of the six specific C2 symptom items were flagged as true by the caller. ## 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": [ "criteria_last_3_months_onset_6_months", "straining_gt_25_percent", "lumpy_or_hard_stools_gt_25_percent", "incomplete_evacuation_gt_25_percent", "anorectal_obstruction_gt_25_percent", "manual_maneuvers_gt_25_percent", "fewer_than_3_sbm_per_week", "loose_stools_rare_without_laxatives", "insufficient_criteria_for_ibs" ], "properties": { "straining_gt_25_percent": { "type": "boolean", "description": "Straining during more than 25% of defecations (one of six C2 symptom items; at least two required). true or false as assigned by the caller. magent does not examine the patient." }, "fewer_than_3_sbm_per_week": { "type": "boolean", "description": "Fewer than three spontaneous bowel movements per week (one of six C2 symptom items; at least two required). true or false as assigned by the caller." }, "insufficient_criteria_for_ibs": { "type": "boolean", "description": "Insufficient criteria for irritable bowel syndrome, as assigned by the caller (Mearin 2016 C2 requires IBS criteria are not met). true or false. magent does not apply the IBS box." }, "manual_maneuvers_gt_25_percent": { "type": "boolean", "description": "Manual maneuvers to facilitate more than 25% of defecations (one of six C2 symptom items; at least two required). true or false as assigned by the caller." }, "lumpy_or_hard_stools_gt_25_percent": { "type": "boolean", "description": "Lumpy or hard stools (Bristol stool form types 1-2) more than 25% of defecations (one of six C2 symptom items; at least two required). true or false as assigned by the caller. magent does not inspect stool." }, "anorectal_obstruction_gt_25_percent": { "type": "boolean", "description": "Sensation of anorectal obstruction/blockage more than 25% of def … (truncated) ``` ## More - Live health (JSON, refreshed every minute): https://www.zero.xyz/c/rome-iv-functional-constipation-c2-calculator-6b5c0137/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)