Neurology · LIVE

Canadian TIA Score

Compute the Perry 2021 Canadian TIA Score from caller-assigned clinical findings and investigations for subsequent 7-day stroke or carotid revascularization risk after TIA.

LIVE $0.005 USDC GET /api/calc/canadian_tia

Markdown: /docs/canadian-tia.md · Canonical: https://magentlab.com/docs/canadian-tia

Not a medical device. Not a diagnosis, dose, or listing recommendation.

What it computes

Compute the Perry 2021 Canadian TIA Score from caller-assigned clinical findings and investigations for subsequent 7-day stroke or carotid revascularization risk after TIA.

When to use

When an agent has caller-assigned ED TIA findings and needs the published Perry 2021 Table 1 total and Table 4 low/medium/high bands, without inventing ABCD2 or an admit order.

When not to use

Not a medical device. Not a stroke diagnosis, TIA diagnosis, or admit order.
This is the Canadian TIA Score (Perry 2021 Table 1), not ABCD2 and not ABCD2i.
Age is required for the adult ED cohort (18-120) and does not add points. magent does not examine the patient, read ECG or CT, or assay platelets or glucose.
Vertigo scores -3 when present (false scores 0). Dysarthria or aphasia scores 1, not 3. Glucose ≥15 mmol/L scores 3 (mg/dL converts as mmol/L = mg/dL / 18).

Formula

Canadian TIA Score = first_tia 2 + symptoms_ge_10_min 2 + carotid_stenosis 2 + on_antiplatelet 3 + gait_disturbance 1 + unilateral_weakness 1 + vertigo -3 + (diastolic_mm_hg >= 110) 3 + dysarthria_or_aphasia 1 + af_on_ecg 2 + infarct_on_ct 1 + (platelets_10e9_l >= 400) 2 + (glucose >= 15 mmol/L) 3; age 18-120 required, 0 points; total -3 to 23; tia_risk low <=3 (0.5%), medium 4-8 (2.3%), high >=9 (5.9%) 7-day stroke or carotid revascularization (Perry 2021 Table 1 / Table 4); max 23

Citation

Title: Prospective validation of Canadian TIA Score and comparison with ABCD2 and ABCD2i for subsequent stroke risk after transient ischaemic attack: multicentre prospective cohort study
Authors: Perry JJ, Sivilotti MLA, Émond M, Stiell IG, Stotts G, Lee J, Worster A, Morris J, Cheung KW, Jin AY, Oczkowski WJ, Sahlas DJ, Murray HE, Mackey A, Verreault S, Camden MC, Yip S, Teal P, Gladstone DJ, Boulos MI, Chagnon N, Shouldice E, Atzema C, Slaoui T, Teitlebaum J, Abdulaziz K, Nemnom MJ, Wells GA, Sharma M
Source: BMJ. 2021;372:n49
DOI: 10.1136/bmj.n49

Worked example

Age 70, all flags false, diastolic 80, platelets 200, glucose 5.0 mmol/L

Given: af_on_ecg=falseage=70carotid_stenosis=falsediastolic_mm_hg=80dysarthria_or_aphasia=falsefirst_tia=falsegait_disturbance=falseglucose_mmol_l=5.0infarct_on_ct=falseon_antiplatelet=falseplatelets_10e9_l=200symptoms_ge_10_min=falseunilateral_weakness=falsevertigo=false

Age 70 is required and scores 0; all clinical and investigation flags false; diastolic 80 <110; platelets 200 <400; glucose 5.0 <15
Score = 0; tia_risk low (≤3; Table 4 0.5%)

Vertigo only

vertigo true → -3; remaining items 0
Score = -3; tia_risk low

First TIA, symptoms ≥10 min, past carotid stenosis, on antiplatelet

Given: af_on_ecg=falseage=70carotid_stenosis=truediastolic_mm_hg=80dysarthria_or_aphasia=falsefirst_tia=truegait_disturbance=falseglucose_mmol_l=5.0infarct_on_ct=falseon_antiplatelet=trueplatelets_10e9_l=200symptoms_ge_10_min=trueunilateral_weakness=falsevertigo=false

first_tia 2 + symptoms_ge_10_min 2 + carotid_stenosis 2 + on_antiplatelet 3
Score = 9; tia_risk high (≥9; Table 4 5.9%)

Also searched as

Canadian TIA Score
Canadian TIA risk score
Perry TIA score
transient ischaemic attack Canadian score
subsequent stroke risk after TIA
Canadian TIA Score Perry 2021
TIA 7-day stroke risk score

Try

Opens the live endpoint. Unpaid browser requests show the paywall; agents should send Accept: application/json.

/api/calc/canadian_tia?age=70&first_tia=false&symptoms_ge_10_min=false&carotid_stenosis=false&on_antiplatelet=false&gait_disturbance=false&unilateral_weakness=false&vertigo=false&diastolic_mm_hg=80&dysarthria_or_aphasia=false&af_on_ecg=false&infarct_on_ct=false&platelets_10e9_l=200&glucose_mmol_l=5.0

Full URL: https://api.magentlab.com/api/calc/canadian_tia?age=70&first_tia=false&symptoms_ge_10_min=false&carotid_stenosis=false&on_antiplatelet=false&gait_disturbance=false&unilateral_weakness=false&vertigo=false&diastolic_mm_hg=80&dysarthria_or_aphasia=false&af_on_ecg=false&infarct_on_ct=false&platelets_10e9_l=200&glucose_mmol_l=5.0

Call

Expect HTTP 402 until you retry with PAYMENT-SIGNATURE. Incomplete query params return HTTP 400 before any quote or charge.

curl -i -H "Accept: application/json" "https://api.magentlab.com/api/calc/canadian_tia?age=70&first_tia=false&symptoms_ge_10_min=false&carotid_stenosis=false&on_antiplatelet=false&gait_disturbance=false&unilateral_weakness=false&vertigo=false&diastolic_mm_hg=80&dysarthria_or_aphasia=false&af_on_ecg=false&infarct_on_ct=false&platelets_10e9_l=200&glucose_mmol_l=5.0"

Parameters

Name	Type	Required	Description
`age`	integer	required	Age in years (18-120). Required for the adult ED cohort. Does not add points (Perry 2021 Table 1 has no age item).
`first_tia`	boolean	required	Lifetime first TIA (Perry 2021 Table 1). true scores 2; false scores 0. Caller-assigned; magent does not take a history.
`symptoms_ge_10_min`	boolean	required	Symptoms lasting 10 minutes or longer (Perry 2021 Table 1). true scores 2; false scores 0. magent does not time the episode.
`carotid_stenosis`	boolean	required	Past history of carotid stenosis (Perry 2021 Table 1). true scores 2; false scores 0. magent does not read imaging.
`on_antiplatelet`	boolean	required	Already on antiplatelet therapy (Perry 2021 Table 1). true scores 3; false scores 0.
`gait_disturbance`	boolean	required	Gait disturbance (Perry 2021 Table 1). true scores 1; false scores 0. magent does not examine the patient.
`unilateral_weakness`	boolean	required	Unilateral weakness (Perry 2021 Table 1). true scores 1; false scores 0. magent does not examine the patient.
`vertigo`	boolean	required	Vertigo (Perry 2021 Table 1). true scores -3; false scores 0. magent does not examine the patient.
`diastolic_mm_hg`	number	required	Initial triage diastolic blood pressure in mm Hg (20-160). ≥110 scores 3; 109 scores 0 (Perry 2021 Table 1).
`dysarthria_or_aphasia`	boolean	required	Dysarthria or aphasia on history or examination (Perry 2021 Table 1). true scores 1; false scores 0. Not 3. magent does not examine the patient.
`af_on_ecg`	boolean	required	Atrial fibrillation on ECG (Perry 2021 Table 1). true scores 2; false scores 0. magent does not read the ECG.
`infarct_on_ct`	boolean	required	New or old infarction on CT (Perry 2021 Table 1). true scores 1; false scores 0. magent does not read the CT.
`platelets_10e9_l`	number	required	Platelet count ×10^9/L (1-2000). ≥400 scores 2; 399 scores 0 (Perry 2021 Table 1).
`glucose_mmol_l`	number	optional	Glucose in mmol/L (2.8-55.5). Provide this or glucose_mg_dl, not both. ≥15.0 scores 3; 14.9 scores 0 (Perry 2021 Table 1).
`glucose_mg_dl`	number	optional	Glucose in mg/dL (50-1000). Converted as mmol/L = mg/dL / 18. Provide this or glucose_mmol_l, not both. ≥15 mmol/L after conversion scores 3.

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.

POST /api/calc/canadian_tia Max 25 unit_amount + extra_item_amount * (n - 1) extra $0.002 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 (fixture)

{
  "items": [
    {
      "af_on_ecg": "false",
      "age": "70",
      "carotid_stenosis": "false",
      "diastolic_mm_hg": "80",
      "dysarthria_or_aphasia": "false",
      "first_tia": "false",
      "gait_disturbance": "false",
      "glucose_mmol_l": "5.0",
      "infarct_on_ct": "false",
      "on_antiplatelet": "false",
      "platelets_10e9_l": "200",
      "symptoms_ge_10_min": "false",
      "unilateral_weakness": "false",
      "vertigo": "false"
    },
    {
      "af_on_ecg": "false",
      "age": "70",
      "carotid_stenosis": "false",
      "diastolic_mm_hg": "80",
      "dysarthria_or_aphasia": "false",
      "first_tia": "false",
      "gait_disturbance": "false",
      "glucose_mmol_l": "5.0",
      "infarct_on_ct": "false",
      "on_antiplatelet": "false",
      "platelets_10e9_l": "200",
      "symptoms_ge_10_min": "false",
      "unilateral_weakness": "false",
      "vertigo": "false"
    }
  ]
}

Open bulk paywall →

Opens a two-item fixture on the API host. Unpaid browsers get the same MetaMask paywall as GET; Pay retries POST with those items.

Example 200 (fixture)

{
  "count": 2,
  "path": "/api/calc/canadian_tia",
  "items": [
    {
      "components": [
        {
          "factor": "first_tia",
          "points": 0,
          "present": false
        },
        {
          "factor": "symptoms_ge_10_min",
          "points": 0,
          "present": false
        },
        {
          "factor": "carotid_stenosis",
          "points": 0,
          "present": false
        },
        {
          "factor": "on_antiplatelet",
          "points": 0,
          "present": false
        },
        {
          "factor": "gait_disturbance",
          "points": 0,
          "present": false
        },
        {
          "factor": "unilateral_weakness",
          "points": 0,
          "present": false
        },
        {
          "factor": "vertigo",
          "points": 0,
          "present": false
        },
        {
          "value": 80.0,
          "factor": "diastolic_mm_hg",
          "points": 0,
          "present": false
        },
        {
          "factor": "dysarthria_or_aphasia",
          "points": 0,
          "present": false
        },
        {
          "factor": "af_on_ecg",
          "points": 0,
          "present": false
        },
        {
          "factor": "infarct_on_ct",
          "points": 0,
          "present": false
        },
        {
          "value": 200.0,
          "factor": "platelets_10e9_l",
          "points": 0,
          "present": false
        },
        {
          "value": 5.0,
          "factor": "glucose",
          "points": 0,
          "present": false
        }
      ],
      "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": "Perry JJ, Sivilotti MLA, Émond M, Stiell IG, Stotts G, Lee J, Worster A, Morris J, Cheung KW, Jin AY, Oczkowski WJ, Sahlas DJ, Murray HE, Mackey A, Verreault S, Camden MC, Yip S, Teal P, Gladstone DJ, Boulos MI, Chagnon N, Shouldice E, Atzema C, Slaoui T, Teitlebaum J, Abdulaziz K, Nemnom MJ, Wells GA, Sharma M",
        "doi": "10.1136/bmj.n49",
        "id": "perry-2021",
        "pmid": "33541890",
        "source": "BMJ. 2021;372:n49",
        "title": "Prospective validation of Canadian TIA Score and comparison with ABCD2 and ABCD2i for subsequent stroke risk after transient ischaemic attack: multicentre prospective cohort study"
      },
      "formula": "canadian_tia",
      "formula_expression": "Canadian TIA Score = first_tia 2 + symptoms_ge_10_min 2 + carotid_stenosis 2 + on_antiplatelet 3 + gait_disturbance 1 + unilateral_weakness 1 + vertigo -3 + (diastolic_mm_hg >= 110) 3 + dysarthria_or_aphasia 1 + af_on_ecg 2 + infarct_on_ct 1 + (platelets_10e9_l >= 400) 2 + (glucose >= 15 mmol/L) 3; age 18-120 required, 0 points; total -3 to 23; tia_risk low <=3 (0.5%), medium 4-8 (2.3%), high >=9 (5.9%) 7-day stroke or carotid revascularization (Perry 2021 Table 1 / Table 4); max 23",
      "diastolic_mm_hg": 80.0,
      "age_years": 70,
      "max_score": 23,
      "score": 0,
      "platelets_10e9_l": 200.0,
      "glucose_mmol_l": 5.0,
      "tia_risk": "low"
    },
    {
      "components": [
        {
          "factor": "first_tia",
          "points": 0,
          "present": false
        },
        {
          "factor": "symptoms_ge_10_min",
          "points": 0,
          "present": false
        },
        {
          "factor": "carotid_stenosis",
          "points": 0,
          "present": false
        },
        {
          "factor": "on_antiplatelet",
          "points": 0,
          "present": false
        },
        {
          "factor": "gait_disturbance",
          "points": 0,
          "present": false
        },
        {
          "factor": "unilateral_weakness",
          "points": 0,
          "present": false
        },
        {
          "factor": "vertigo",
          "points": 0,
          "present": false
        },
        {
          "value": 80.0,
          "factor": "diastolic_mm_hg",
          "points": 0,
          "present": false
        },
        {
          "factor": "dysarthria_or_aphasia",
          "points": 0,
          "present": false
        },
        {
          "factor": "af_on_ecg",
          "points": 0,
          "present": false
        },
        {
          "factor": "infarct_on_ct",
          "points": 0,
          "present": false
        },
        {
          "value": 200.0,
          "factor": "platelets_10e9_l",
          "points": 0,
          "present": false
        },
        {
          "value": 5.0,
          "factor": "glucose",
          "points": 0,
          "present": false
        }
      ],
      "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": "Perry JJ, Sivilotti MLA, Émond M, Stiell IG, Stotts G, Lee J, Worster A, Morris J, Cheung KW, Jin AY, Oczkowski WJ, Sahlas DJ, Murray HE, Mackey A, Verreault S, Camden MC, Yip S, Teal P, Gladstone DJ, Boulos MI, Chagnon N, Shouldice E, Atzema C, Slaoui T, Teitlebaum J, Abdulaziz K, Nemnom MJ, Wells GA, Sharma M",
        "doi": "10.1136/bmj.n49",
        "id": "perry-2021",
        "pmid": "33541890",
        "source": "BMJ. 2021;372:n49",
        "title": "Prospective validation of Canadian TIA Score and comparison with ABCD2 and ABCD2i for subsequent stroke risk after transient ischaemic attack: multicentre prospective cohort study"
      },
      "formula": "canadian_tia",
      "formula_expression": "Canadian TIA Score = first_tia 2 + symptoms_ge_10_min 2 + carotid_stenosis 2 + on_antiplatelet 3 + gait_disturbance 1 + unilateral_weakness 1 + vertigo -3 + (diastolic_mm_hg >= 110) 3 + dysarthria_or_aphasia 1 + af_on_ecg 2 + infarct_on_ct 1 + (platelets_10e9_l >= 400) 2 + (glucose >= 15 mmol/L) 3; age 18-120 required, 0 points; total -3 to 23; tia_risk low <=3 (0.5%), medium 4-8 (2.3%), high >=9 (5.9%) 7-day stroke or carotid revascularization (Perry 2021 Table 1 / Table 4); max 23",
      "diastolic_mm_hg": 80.0,
      "age_years": 70,
      "max_score": 23,
      "score": 0,
      "platelets_10e9_l": 200.0,
      "glucose_mmol_l": 5.0,
      "tia_risk": "low"
    }
  ]
}

Response

Field	Type	Description
`formula`	string	canadian_tia
`formula_expression`	string	Exact expression used
`score`	integer	Canadian TIA Score total from -3 to 23
`max_score`	integer	Always 23
`tia_risk`	string	low (score ≤3, 0.5%), medium (4-8, 2.3%), or high (≥9, 5.9%) 7-day stroke or carotid revascularization observed risk (Perry 2021 Table 4)
`age_years`	integer	Age used for the adult clamp; not a Table 1 point item
`diastolic_mm_hg`	number	Initial triage diastolic blood pressure used for the ≥110 item
`platelets_10e9_l`	number	Platelet count used for the ≥400 item (×10^9/L)
`glucose_mmol_l`	number	Glucose in mmol/L (mg/dL inputs converted /18) used for the ≥15 item
`components`	array	Per-factor points
`citation`	object	Perry 2021 BMJ citation
`disclaimer`	string	Not-a-device notice

Example JSON

Machine form of the same example. Frozen fixture. Not a live lookup.

{
  "components": [
    {
      "factor": "first_tia",
      "points": 0,
      "present": false
    },
    {
      "factor": "symptoms_ge_10_min",
      "points": 0,
      "present": false
    },
    {
      "factor": "carotid_stenosis",
      "points": 0,
      "present": false
    },
    {
      "factor": "on_antiplatelet",
      "points": 0,
      "present": false
    },
    {
      "factor": "gait_disturbance",
      "points": 0,
      "present": false
    },
    {
      "factor": "unilateral_weakness",
      "points": 0,
      "present": false
    },
    {
      "factor": "vertigo",
      "points": 0,
      "present": false
    },
    {
      "value": 80.0,
      "factor": "diastolic_mm_hg",
      "points": 0,
      "present": false
    },
    {
      "factor": "dysarthria_or_aphasia",
      "points": 0,
      "present": false
    },
    {
      "factor": "af_on_ecg",
      "points": 0,
      "present": false
    },
    {
      "factor": "infarct_on_ct",
      "points": 0,
      "present": false
    },
    {
      "value": 200.0,
      "factor": "platelets_10e9_l",
      "points": 0,
      "present": false
    },
    {
      "value": 5.0,
      "factor": "glucose",
      "points": 0,
      "present": false
    }
  ],
  "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": "Perry JJ, Sivilotti MLA, Émond M, Stiell IG, Stotts G, Lee J, Worster A, Morris J, Cheung KW, Jin AY, Oczkowski WJ, Sahlas DJ, Murray HE, Mackey A, Verreault S, Camden MC, Yip S, Teal P, Gladstone DJ, Boulos MI, Chagnon N, Shouldice E, Atzema C, Slaoui T, Teitlebaum J, Abdulaziz K, Nemnom MJ, Wells GA, Sharma M",
    "doi": "10.1136/bmj.n49",
    "id": "perry-2021",
    "pmid": "33541890",
    "source": "BMJ. 2021;372:n49",
    "title": "Prospective validation of Canadian TIA Score and comparison with ABCD2 and ABCD2i for subsequent stroke risk after transient ischaemic attack: multicentre prospective cohort study"
  },
  "formula": "canadian_tia",
  "formula_expression": "Canadian TIA Score = first_tia 2 + symptoms_ge_10_min 2 + carotid_stenosis 2 + on_antiplatelet 3 + gait_disturbance 1 + unilateral_weakness 1 + vertigo -3 + (diastolic_mm_hg >= 110) 3 + dysarthria_or_aphasia 1 + af_on_ecg 2 + infarct_on_ct 1 + (platelets_10e9_l >= 400) 2 + (glucose >= 15 mmol/L) 3; age 18-120 required, 0 points; total -3 to 23; tia_risk low <=3 (0.5%), medium 4-8 (2.3%), high >=9 (5.9%) 7-day stroke or carotid revascularization (Perry 2021 Table 1 / Table 4); max 23",
  "diastolic_mm_hg": 80.0,
  "age_years": 70,
  "max_score": 23,
  "score": 0,
  "platelets_10e9_l": 200.0,
  "glucose_mmol_l": 5.0,
  "tia_risk": "low"
}

Client errors (HTTP 400)

Invalid params return 400 without charge. Shared HTTP 402 and 503 meanings: Payments.

HTTP	Code	When
400	`invalid_age`	age must be an integer from 18 to 120 Returned before settlement; you are not charged.
400	`invalid_flag`	boolean clinical flags must be true or false Returned before settlement; you are not charged.
400	`invalid_diastolic_bp`	diastolic_mm_hg must be a number from 20 to 160. Returned before settlement; you are not charged.
400	`invalid_platelets`	platelets_10e9_l must be a number from 1 to 2000 Returned before settlement; you are not charged.
400	`invalid_glucose`	glucose_mg_dl (50-1000) or glucose_mmol_l (2.8-55.5) is required Returned before settlement; you are not charged.
400	`invalid_items`	POST body must be a JSON object with only an items array Returned before settlement; you are not charged.
400	`invalid_item_count`	items must be an array of 1 to 25 objects Returned before settlement; you are not charged.
400	`invalid_item`	each items entry must be a JSON object Returned before settlement; you are not charged.

Related tools

ABCD2 score — Compute the ABCD2 score as age, blood pressure, caller-assigned clinical features, symptom duration, and diabetes.

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. Unpaid valid requests return HTTP 402 with a base64 PAYMENT-REQUIRED header. HTTP 503 is not a new quote: retry the same PAYMENT-SIGNATURE. Full handshake and shared payment errors: Payments. Stdio MCP: /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. HTTP 402 never includes the tool JSON.
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.