# CHALICE pediatric head CT CHALICE Status: LIVE Price: $0.005 USDC `GET /api/calc/chalice` HTML: https://magentlab.com/docs/chalice Markdown: https://magentlab.com/docs/chalice.md Not a medical device. Not a diagnosis, dose, or listing recommendation. ## What it computes Apply the Dunning 2006 CHALICE rule and return whether CT is required from caller-assigned history, examination, and mechanism findings after head injury in a child younger than 16. ## When to use When an agent has caller-assigned findings after head injury in a child 0-15 years and needs the Dunning 2006 CHALICE CT rule, not PECARN, CATCH, or Canadian CT Head. ## When not to use - Not a medical device. Not a diagnosis. magent does not examine the child. - This tool is the Dunning 2006 CHALICE rule only. It is not PECARN, not CATCH, and not the Canadian CT Head Rule. - Age is integer years 0-15 (children younger than 16). GCS is an integer 3-15 as assigned by the caller. - The GCS criterion is GCS <14, or GCS <15 if age <1 year. Bruise, swelling, or laceration >5 cm requires CT only when age <1 year; the flag is parsed but does not score at age 1-15. - Mechanism findings are caller-assigned (paper: high-speed RTA >40 mph as occupant, pedestrian, or cyclist; fall >3 m; high-speed injury from a projectile or object). magent does not classify mechanism. - Suspicion of non-accidental injury is caller-assigned. magent does not diagnose NAI. ## Formula ``` CT required if any history, examination, or mechanism criterion is present; else low risk. GCS <14, or GCS <15 if age <1 year. Bruise, swelling, or laceration >5 cm only if age <1 year. Mechanism is caller-assigned. ``` ## Citation [Derivation of the children's head injury algorithm for the prediction of important clinical events decision rule for head injury in children](https://doi.org/10.1136/adc.2005.083980) Dunning J, Daly JP, Lomas JP, Lecky F, Batchelor J, Mackway-Jones K Arch Dis Child. 2006;91(11):885-891 DOI: [10.1136/adc.2005.083980](https://doi.org/10.1136/adc.2005.083980) ## Worked example ### Age 10, GCS 15, all flags false Given: `abnormal_drowsiness=false, age=10, amnesia_gt_5_min=false, basal_skull_fracture=false, bruise_swelling_laceration_gt_5cm=false, fall_gt_3m=false, focal_neurology=false, gcs=15, high_speed_projectile_or_object=false, high_speed_rta=false, loc_gt_5_min=false, penetrating_depressed_or_tense_fontanelle=false, seizure_no_epilepsy=false, suspicion_nai=false, vomits_ge_3=false` 1. Age 10 uses GCS <14; GCS 15 does not meet the GCS criterion 2. No history, examination, or mechanism flag is present 3. CHALICE low risk; CT is not required ### Age 10, GCS 13 requires CT Given: `abnormal_drowsiness=false, age=10, amnesia_gt_5_min=false, basal_skull_fracture=false, bruise_swelling_laceration_gt_5cm=false, fall_gt_3m=false, focal_neurology=false, gcs=13, high_speed_projectile_or_object=false, high_speed_rta=false, loc_gt_5_min=false, penetrating_depressed_or_tense_fontanelle=false, seizure_no_epilepsy=false, suspicion_nai=false, vomits_ge_3=false` 1. Age 10 is >=1 year, so GCS <14 meets the GCS criterion 2. CHALICE CT required ### Age 0 bruise >5 cm requires CT Given: `abnormal_drowsiness=false, age=0, amnesia_gt_5_min=false, basal_skull_fracture=false, bruise_swelling_laceration_gt_5cm=true, fall_gt_3m=false, focal_neurology=false, gcs=15, high_speed_projectile_or_object=false, high_speed_rta=false, loc_gt_5_min=false, penetrating_depressed_or_tense_fontanelle=false, seizure_no_epilepsy=false, suspicion_nai=false, vomits_ge_3=false` 1. Age 0 is <1 year, so bruise, swelling, or laceration >5 cm scores 2. CHALICE CT required ## Also searched as - CHALICE - children's head injury algorithm - Dunning 2006 - CHALICE head CT - pediatric CHALICE rule - Children's Head injury ALgorithm for the prediction of Important Clinical Events - CHALICE CT rule - Dunning CHALICE ## Parameters - `age` (integer, required): Age in whole years (0-15). CHALICE is for children younger than 16. Age 0 is younger than 1 year (GCS <15 and bruise >5 cm apply). Age 1-15 uses GCS <14. Age 16 is rejected. - `gcs` (integer, required): Glasgow Coma Scale total, integer 3-15 as assigned by the caller. Examination criterion: GCS <14, or GCS <15 if age <1 year. - `loc_gt_5_min` (boolean, required): Witnessed loss of consciousness >5 minutes. true or false as assigned by the caller. History criterion. magent does not take a duration integer. - `amnesia_gt_5_min` (boolean, required): Amnesia (anterograde or retrograde) >5 minutes. true or false as assigned by the caller. History criterion. magent does not take a duration integer. - `abnormal_drowsiness` (boolean, required): Abnormal drowsiness. true or false as assigned by the caller. History criterion. magent does not examine the child. - `vomits_ge_3` (boolean, required): Three or more vomits after the head injury. true or false as assigned by the caller. History criterion. - `suspicion_nai` (boolean, required): Suspicion of non-accidental injury as assigned by the caller. true or false. History criterion. magent does not diagnose NAI. - `seizure_no_epilepsy` (boolean, required): Seizure after the head injury in a child with no history of epilepsy. true or false as assigned by the caller. History criterion. - `penetrating_depressed_or_tense_fontanelle` (boolean, required): Suspicion of penetrating or depressed skull injury or tense fontanelle. true or false as assigned by the caller. Examination criterion. magent does not examine the child. - `basal_skull_fracture` (boolean, required): Signs of basal skull fracture. true or false as assigned by the caller. Examination criterion. magent does not examine the child. - `focal_neurology` (boolean, required): Positive focal neurology. true or false as assigned by the caller. Examination criterion. magent does not examine the child. - `bruise_swelling_laceration_gt_5cm` (boolean, required): Bruise, swelling, or laceration >5 cm. true or false as assigned by the caller. Examination criterion that scores only when age <1 year; parsed but not scored when age >= 1. magent does not measure the lesion. - `high_speed_rta` (boolean, required): High-speed road traffic accident as occupant, pedestrian, or cyclist as assigned by the caller (paper: speed >40 mph). true or false. Mechanism criterion. magent does not classify mechanism. - `fall_gt_3m` (boolean, required): Fall >3 m as assigned by the caller. true or false. Mechanism criterion. magent does not classify mechanism or take a height integer. - `high_speed_projectile_or_object` (boolean, required): High-speed injury from a projectile or object as assigned by the caller. true or false. Mechanism criterion. magent does not classify mechanism. ## Bulk (POST) POST the same path with a JSON items array. The first item is the GET unit; each additional item is $0.002. Invalid items return HTTP 400 before settlement. Method: `POST /api/calc/chalice` Max items: 25 Price: unit_amount + extra_item_amount * (n - 1) (unit 5000 atomic, extra 2000 atomic) Status: PREVIEW - 1 to 25 items. Each item uses the same keys as the GET query parameters. - POST of 1 item costs the same as GET. Lists longer than 25: chunk into multiple POSTs. Extra items still execute; do not pad dummy rows. - The first invalid item fails the whole request (index in the 400 JSON). You are not charged. - HTTP 200 is {count, path, items}. Each items[i] is the GET 200 body for that row. - Catalog misses (empty matches, found=false) stay paid 200s inside that slot. - x402 resource URL is this path plus n and body_sha256. Browsers that prefer text/html get the same paywall as GET; Pay retries POST with the same items. Example request: ```json { "items": [ { "abnormal_drowsiness": "false", "age": "10", "amnesia_gt_5_min": "false", "basal_skull_fracture": "false", "bruise_swelling_laceration_gt_5cm": "false", "fall_gt_3m": "false", "focal_neurology": "false", "gcs": "15", "high_speed_projectile_or_object": "false", "high_speed_rta": "false", "loc_gt_5_min": "false", "penetrating_depressed_or_tense_fontanelle": "false", "seizure_no_epilepsy": "false", "suspicion_nai": "false", "vomits_ge_3": "false" }, { "abnormal_drowsiness": "false", "age": "10", "amnesia_gt_5_min": "false", "basal_skull_fracture": "false", "bruise_swelling_laceration_gt_5cm": "false", "fall_gt_3m": "false", "focal_neurology": "false", "gcs": "15", "high_speed_projectile_or_object": "false", "high_speed_rta": "false", "loc_gt_5_min": "false", "penetrating_depressed_or_tense_fontanelle": "false", "seizure_no_epilepsy": "false", "suspicion_nai": "false", "vomits_ge_3": "false" } ] } ``` Human paywall (two-item fixture): https://api.magentlab.com/paywall/bulk/chalice Example 200: ```json { "count": 2, "path": "/api/calc/chalice", "items": [ { "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.", "citation": { "authors": "Dunning J, Daly JP, Lomas JP, Lecky F, Batchelor J, Mackway-Jones K", "doi": "10.1136/adc.2005.083980", "id": "dunning-2006", "pmid": "17056862", "source": "Arch Dis Child. 2006;91(11):885-891", "title": "Derivation of the children's head injury algorithm for the prediction of important clinical events decision rule for head injury in children" }, "formula": "chalice", "formula_expression": "CT required if any history, examination, or mechanism criterion is present; else low risk. GCS <14, or GCS <15 if age <1 year. Bruise, swelling, or laceration >5 cm only if age <1 year. Mechanism is caller-assigned.", "age_years": 10, "criteria": [ { "factor": "loc_gt_5_min", "met": false }, { "factor": "amnesia_gt_5_min", "met": false }, { "factor": "abnormal_drowsiness", "met": false }, { "factor": "vomits_ge_3", "met": false }, { "factor": "suspicion_nai", "met": false }, { "factor": "seizure_no_epilepsy", "met": false }, { "value": 15, "factor": "gcs_criterion", "met": false }, { "factor": "penetrating_depressed_or_tense_fontanelle", "met": false }, { "factor": "basal_skull_fracture", "met": false }, { "factor": "focal_neurology", "met": false }, { "value": 10, "factor": "bruise_swelling_laceration_gt_5cm", "met": false }, { "factor": "high_speed_rta", "met": false }, { "factor": "fall_gt_3m", "met": false }, { "factor": "high_speed_projectile_or_object", "met": false } ], "chalice_ct_required": false, "chalice_low_risk": true, "gcs": 15 }, { "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.", "citation": { "authors": "Dunning J, Daly JP, Lomas JP, Lecky F, Batchelor J, Mackway-Jones K", "doi": "10.1136/adc.2005.083980", "id": "dunning-2006", "pmid": "17056862", "source": "Arch Dis Child. 2006;91(11):885-891", "title": "Derivation of the children's head injury algorithm for the prediction of important clinical events decision rule for head injury in children" }, "formula": "chalice", "formula_expression": "CT required if any history, examination, or mechanism criterion is present; else low risk. GCS <14, or GCS <15 if age <1 year. Bruise, swelling, or laceration >5 cm only if age <1 year. Mechanism is caller-assigned.", "age_years": 10, "criteria": [ { "factor": "loc_gt_5_min", "met": false }, { "factor": "amnesia_gt_5_min", "met": false }, { "factor": "abnormal_drowsiness", "met": false }, { "factor": "vomits_ge_3", "met": false }, { "factor": "suspicion_nai", "met": false }, { "factor": "seizure_no_epilepsy", "met": false }, { "value": 15, "factor": "gcs_criterion", "met": false }, { "factor": "penetrating_depressed_or_tense_fontanelle", "met": false }, { "factor": "basal_skull_fracture", "met": false }, { "factor": "focal_neurology", "met": false }, { "value": 10, "factor": "bruise_swelling_laceration_gt_5cm", "met": false }, { "factor": "high_speed_rta", "met": false }, { "factor": "fall_gt_3m", "met": false }, { "factor": "high_speed_projectile_or_object", "met": false } ], "chalice_ct_required": false, "chalice_low_risk": true, "gcs": 15 } ] } ``` ## Response fields - `formula` (string): chalice - `formula_expression` (string): Dunning 2006 CHALICE any-criterion CT rule - `age_years` (integer): Age in years used for age-gated criteria - `gcs` (integer): GCS total used for the GCS criterion - `chalice_ct_required` (boolean): true when any published CHALICE criterion is met. Not a diagnosis and not an order for CT. - `chalice_low_risk` (boolean): true when no published CHALICE criterion is met (the negation of chalice_ct_required) - `criteria` (array): Per-factor rows with factor and met. gcs_criterion is computed from age and GCS. bruise_swelling_laceration_gt_5cm is met only when age <1 year and the flag is true. - `citation` (object): Dunning 2006 Arch Dis Child citation - `disclaimer` (string): Not-a-device notice ## Example JSON Frozen fixture. Not a live lookup. ```json { "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.", "citation": { "authors": "Dunning J, Daly JP, Lomas JP, Lecky F, Batchelor J, Mackway-Jones K", "doi": "10.1136/adc.2005.083980", "id": "dunning-2006", "pmid": "17056862", "source": "Arch Dis Child. 2006;91(11):885-891", "title": "Derivation of the children's head injury algorithm for the prediction of important clinical events decision rule for head injury in children" }, "formula": "chalice", "formula_expression": "CT required if any history, examination, or mechanism criterion is present; else low risk. GCS <14, or GCS <15 if age <1 year. Bruise, swelling, or laceration >5 cm only if age <1 year. Mechanism is caller-assigned.", "age_years": 10, "criteria": [ { "factor": "loc_gt_5_min", "met": false }, { "factor": "amnesia_gt_5_min", "met": false }, { "factor": "abnormal_drowsiness", "met": false }, { "factor": "vomits_ge_3", "met": false }, { "factor": "suspicion_nai", "met": false }, { "factor": "seizure_no_epilepsy", "met": false }, { "value": 15, "factor": "gcs_criterion", "met": false }, { "factor": "penetrating_depressed_or_tense_fontanelle", "met": false }, { "factor": "basal_skull_fracture", "met": false }, { "factor": "focal_neurology", "met": false }, { "value": 10, "factor": "bruise_swelling_laceration_gt_5cm", "met": false }, { "factor": "high_speed_rta", "met": false }, { "factor": "fall_gt_3m", "met": false }, { "factor": "high_speed_projectile_or_object", "met": false } ], "chalice_ct_required": false, "chalice_low_risk": true, "gcs": 15 } ``` ## Errors - HTTP 400 `invalid_chalice_age`: age must be an integer from 0 to 15 (Dunning 2006 CHALICE, children younger than 16). Returned before settlement; you are not charged. - HTTP 400 `invalid_gcs_total`: gcs must be an integer from 3 to 15. Returned before settlement; you are not charged. - HTTP 400 `invalid_flag`: boolean clinical flags must be true or false Returned before settlement; you are not charged. - HTTP 400 `invalid_items`: POST body must be a JSON object with only an items array Returned before settlement; you are not charged. - HTTP 400 `invalid_item_count`: items must be an array of 1 to 25 objects Returned before settlement; you are not charged. - HTTP 400 `invalid_item`: each items entry must be a JSON object Returned before settlement; you are not charged. Shared HTTP 402 and 503: https://magentlab.com/docs/payments ## Related tools - [PECARN pediatric head CT](https://magentlab.com/docs/pecarn-head) — Apply the Kuppermann 2009 PECARN prediction trees and return high, intermediate, or low risk of clinically important brain injury from caller-assigned findings after pediatric head trauma. - [CATCH](https://magentlab.com/docs/catch) — Apply the Osmond 2010 CATCH derivation and return high, medium, or low risk plus whether CT of the head is indicated from seven caller-assigned findings after pediatric minor head injury. - [Canadian CT Head Rule](https://magentlab.com/docs/canadian-ct-head) — Apply the Stiell 2001 Canadian CT Head Rule and return whether CT is indicated from caller-assigned high-risk and medium-risk findings after minor blunt head injury. ## Payment Unpaid requests return HTTP 402 even if query parameters or POST items are missing or invalid, so CDP and agents can index the path. After a PAYMENT-SIGNATURE, invalid params return HTTP 400 JSON before settlement. magent does not charge. Fix the params, then request a new 402 quote for that complete URL. Catalog misses (empty matches, found=false) are valid paid 200s. - GET the tool with Accept: application/json (do not send Accept: text/html unless you want the human paywall). - HTTP 402 means you have not paid. Decode the base64 PAYMENT-REQUIRED header. HTTP 503 is not a new quote. - Sign accepts[0] (exact, EIP-3009) with validBefore = now + maxTimeoutSeconds (600 seconds), or accepts[1] (batch-settlement deposit/voucher) on product GET. Ping and POST {items} stay exact. Magent retries transient facilitator 429/5xx before answering. - Retry the same URL with PAYMENT-SIGNATURE (base64 JSON of accepted and payload). Magent attaches canonical extensions.bazaar on CDP verify/settle; echoing 402 bazaar is optional. - Success is HTTP 200 JSON plus PAYMENT-RESPONSE. exact settles before the tool. batch-settlement verifies (and deposit-settles) before the tool and commits the charge after HTTP 2xx. HTTP 503: retry the same PAYMENT-SIGNATURE. Mint a new exact nonce only after a new HTTP 402. - offered `exact` on eip155:8453: Fixed-price USDC on Base. The buyer authorizes the advertised amount (EIP-3009). magent settles before the tool runs (paymentFlow upfront). extra.assetTransferMethod=eip3009 extra.paymentFlow=upfront. - offered `batch-settlement` on eip155:8453: Payment-channel vouchers claimed later in batches. Exact stays accepts[0]. Same-path POST {items} is still exact. extra.assetTransferMethod=eip3009 extra.paymentFlow=authorization. - not offered `upto`: Not offered. Usage-based: buyer authorizes a ceiling, seller settles the actual amount after work. Reserved for a future metered tool. Not for current calculators or code search. Same-path POST {items} is still scheme exact: one EIP-3009 authorization for GET unit plus $0.002 per extra item. That is not x402 batch-settlement (payment channels / vouchers). Shared HTTP 402 and 503 table: https://magentlab.com/docs/payments Stdio MCP (one process per host): https://magentlab.com/docs/mcp ## Guarantees - HTTP 402 is unpaid, including a missing query. After PAYMENT-SIGNATURE, invalid parameters return HTTP 400 before settlement. You are not charged. - exact: settlement finishes before the tool (paymentFlow upfront). batch-settlement: verify/deposit before the tool; chargedCumulativeAmount commits after HTTP 2xx. Uncertain or failed settlement fails closed (HTTP 503). Retry the same PAYMENT-SIGNATURE. - HTTP 402 is unpaid only. Do not sign a second authorization because of a 503. - Execution is timeout-bounded and concurrency-capped. - Calculator inputs are stored encrypted for allowlisted operators (Magent Console). They are not in public logs, SSH lookups, catalog, or rollups. Request logs store path without query.