# TIMI risk index

TIMI risk index

Status: LIVE
Price: $0.005 USDC
`GET /api/calc/timi_risk_index`
HTML: https://magentlab.com/docs/timi-risk-index
Markdown: https://magentlab.com/docs/timi-risk-index.md

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

## What it computes

Compute the Morrow 2001 TIMI risk index HR × (age/10)^2 / SBP and the InTIME-II five-group cutpoints.

## When to use

When an agent needs the published STEMI triage index and must not invent a reperfusion or fibrinolytic decision.

## When not to use

- Not a reperfusion, fibrinolytic, or triage-center order. Groups are Morrow 2001 InTIME-II cutpoints, not a diagnosis.
- Derivation excluded HR <50 or >150 and SBP <60 or >200 mm Hg. magent still returns the arithmetic outside those windows.
- This is the three-variable risk index (Lancet 2001), not the eight-item TIMI STEMI score.

## Formula

```
timi_risk_index = heart_rate_bpm * (age_years / 10)^2 / systolic_mm_hg
```

## Citation

[A simple risk index for rapid initial triage of patients with ST-elevation myocardial infarction: an InTIME II substudy](https://doi.org/10.1016/S0140-6736(01)06649-1)
Morrow DA, Antman EM, Giugliano RP, et al.
Lancet. 2001;358(9293):1571-1575
DOI: [10.1016/S0140-6736(01)06649-1](https://doi.org/10.1016/S0140-6736(01)06649-1)

## Worked example

### Age 65, HR 80, SBP 120

Given: `age=65, heart_rate_bpm=80, systolic_mm_hg=120`

1. (age/10)^2 = 42.25
2. TRI = 80 × 42.25 / 120 = 28.2
3. group 4 (>22.5 to 30)


### Age 40, HR 60, SBP 140

Given: `age=40, heart_rate_bpm=60, systolic_mm_hg=140`

1. TRI = 60 × 16 / 140 = 6.9
2. group 1 (≤12.5)


## Also searched as

- TIMI risk index
- Morrow risk index
- InTIME II risk index
- TRI STEMI
- simple STEMI risk index

## Parameters

- `age` (integer, required): Age in years (18-120).
- `heart_rate_bpm` (integer, required): Admission heart rate in beats per minute (integer 30-220). Morrow 2001 excluded HR <50 or >150 from derivation; magent still computes the index.
- `systolic_mm_hg` (number, required): Admission systolic blood pressure in mm Hg (50-250). Morrow 2001 excluded SBP <60 or >200 from derivation; magent still computes the index.

## 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/timi_risk_index`
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": [
    {
      "age": "65",
      "heart_rate_bpm": "80",
      "systolic_mm_hg": "120"
    },
    {
      "age": "65",
      "heart_rate_bpm": "80",
      "systolic_mm_hg": "120"
    }
  ]
}
```

Human paywall (two-item fixture): https://api.magentlab.com/paywall/bulk/timi-risk-index

Example 200:

```json
{
  "count": 2,
  "path": "/api/calc/timi_risk_index",
  "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": "Morrow DA, Antman EM, Giugliano RP, et al.",
        "doi": "10.1016/S0140-6736(01)06649-1",
        "id": "morrow-2001",
        "source": "Lancet. 2001;358(9293):1571-1575",
        "title": "A simple risk index for rapid initial triage of patients with ST-elevation myocardial infarction: an InTIME II substudy"
      },
      "formula": "timi_risk_index",
      "formula_expression": "timi_risk_index = heart_rate_bpm * (age_years / 10)^2 / systolic_mm_hg",
      "age_years": 65,
      "systolic_mm_hg": 120.0,
      "heart_rate_bpm": 80,
      "risk_group": 4,
      "timi_risk_index": 28.2
    },
    {
      "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": "Morrow DA, Antman EM, Giugliano RP, et al.",
        "doi": "10.1016/S0140-6736(01)06649-1",
        "id": "morrow-2001",
        "source": "Lancet. 2001;358(9293):1571-1575",
        "title": "A simple risk index for rapid initial triage of patients with ST-elevation myocardial infarction: an InTIME II substudy"
      },
      "formula": "timi_risk_index",
      "formula_expression": "timi_risk_index = heart_rate_bpm * (age_years / 10)^2 / systolic_mm_hg",
      "age_years": 65,
      "systolic_mm_hg": 120.0,
      "heart_rate_bpm": 80,
      "risk_group": 4,
      "timi_risk_index": 28.2
    }
  ]
}
```

## Response fields

- `formula` (string): timi_risk_index
- `formula_expression` (string): Exact expression used
- `age_years` (integer): Age used
- `heart_rate_bpm` (integer): Heart rate used, bpm
- `systolic_mm_hg` (number): Systolic pressure used, mm Hg
- `timi_risk_index` (number): HR × (age/10)^2 / SBP, 1 decimal
- `risk_group` (integer): Morrow 2001 InTIME-II group: 1 if ≤12.5; 2 if >12.5–17.5; 3 if >17.5–22.5; 4 if >22.5–30; 5 if >30. A band, not a reperfusion order.
- `citation` (object): Morrow et al. Lancet 2001 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": "Morrow DA, Antman EM, Giugliano RP, et al.",
    "doi": "10.1016/S0140-6736(01)06649-1",
    "id": "morrow-2001",
    "source": "Lancet. 2001;358(9293):1571-1575",
    "title": "A simple risk index for rapid initial triage of patients with ST-elevation myocardial infarction: an InTIME II substudy"
  },
  "formula": "timi_risk_index",
  "formula_expression": "timi_risk_index = heart_rate_bpm * (age_years / 10)^2 / systolic_mm_hg",
  "age_years": 65,
  "systolic_mm_hg": 120.0,
  "heart_rate_bpm": 80,
  "risk_group": 4,
  "timi_risk_index": 28.2
}
```

## Errors

- HTTP 400 `invalid_age`: age must be an integer from 18 to 120 Returned before settlement; you are not charged.
- HTTP 400 `invalid_heart_rate`: heart_rate_bpm must be an integer from 30 to 220 Returned before settlement; you are not charged.
- HTTP 400 `invalid_systolic_bp`: systolic_mm_hg or systolic_bp_mm_hg must be a number from 50 to 250. 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

- [TIMI risk score for STEMI](https://magentlab.com/docs/timi-stemi) — Compute the TIMI risk score for ST-elevation myocardial infarction from published bedside factors at presentation.
- [TIMI UA/NSTEMI](https://magentlab.com/docs/timi-ua-nstemi) — Compute the TIMI risk score for unstable angina / NSTEMI from age and six caller-assigned flags.
- [HEART score](https://magentlab.com/docs/heart) — Compute the HEART score as age points plus caller-assigned history, ECG, risk factors, and troponin (each 0-2).

## 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 echoing accepted, payload, and extensions when present).
- 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.