# IV alteplase dose (NINDS)

Alteplase stroke dose

Status: LIVE
Price: $0.005 USDC
`GET /api/calc/alteplase_stroke`
HTML: https://magentlab.com/docs/alteplase-stroke
Markdown: https://magentlab.com/docs/alteplase-stroke.md

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

## What it computes

Compute NINDS 1995 intravenous alteplase milligrams from weight: 0.9 mg/kg capped at 90 mg, with 10% as a bolus and the remainder over 60 minutes.

## When to use

When an agent needs published NINDS 1995 alteplase milligram arithmetic and must not invent eligibility, door-to-needle time, blood-pressure targets, or a tenecteplase dose.

## When not to use

- Not a medical device. A licensed clinician remains responsible for the prescription and administration.
- Not a prescription and not an eligibility screen. magent does not encode NINDS exclusion criteria, door-to-needle time, or blood-pressure targets.
- Alteplase milligrams only. Not tenecteplase.

## Formula

```
total_mg = min(0.9 * weight_kg, 90.0); bolus_mg = 0.10 * total_mg; infusion_mg = 0.90 * total_mg; infusion_minutes = 60
```

## Citation

[Tissue plasminogen activator for acute ischemic stroke](https://doi.org/10.1056/NEJM199512143332401)
National Institute of Neurological Disorders and Stroke rt-PA Stroke Study Group
N Engl J Med. 1995;333(24):1581-1587
DOI: [10.1056/NEJM199512143332401](https://doi.org/10.1056/NEJM199512143332401)

## Worked example

### 80 kg, below the 90 mg cap

Given: `weight_kg=80`

1. total_mg = min(0.9 × 80, 90) = 72.0 mg
2. bolus_mg = 0.10 × 72.0 = 7.2 mg
3. infusion_mg = 0.90 × 72.0 = 64.8 mg over 60 minutes
4. capped = false


### 120 kg, 90 mg cap

Given: `weight_kg=120`

1. 0.9 × 120 = 108.0 mg, so total_mg = 90.0 mg
2. bolus_mg = 0.10 × 90.0 = 9.0 mg
3. infusion_mg = 0.90 × 90.0 = 81.0 mg over 60 minutes
4. capped = true


## Also searched as

- alteplase dose
- IV alteplase milligrams
- NINDS alteplase dose
- stroke alteplase weight
- alteplase bolus infusion
- 0.9 mg/kg alteplase
- alteplase 90 mg cap

## Parameters

- `weight_kg` (number, required): Weight in kilograms (1-500). NINDS 1995 dose is 0.9 mg/kg, maximum 90 mg. magent clamp, not an eligibility band.

## 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/alteplase_stroke`
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": [
    {
      "weight_kg": "80"
    },
    {
      "weight_kg": "80"
    }
  ]
}
```

Human paywall (two-item fixture): https://api.magentlab.com/paywall/bulk/alteplase-stroke

Example 200:

```json
{
  "count": 2,
  "path": "/api/calc/alteplase_stroke",
  "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": "National Institute of Neurological Disorders and Stroke rt-PA Stroke Study Group",
        "doi": "10.1056/NEJM199512143332401",
        "id": "ninds-1995",
        "pmid": "7477192",
        "source": "N Engl J Med. 1995;333(24):1581-1587",
        "title": "Tissue plasminogen activator for acute ischemic stroke"
      },
      "formula": "alteplase_stroke",
      "formula_expression": "total_mg = min(0.9 * weight_kg, 90.0); bolus_mg = 0.10 * total_mg; infusion_mg = 0.90 * total_mg; infusion_minutes = 60",
      "weight_kg": 80.0,
      "bolus_mg": 7.2,
      "capped": false,
      "infusion_mg": 64.8,
      "infusion_minutes": 60,
      "total_mg": 72.0
    },
    {
      "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": "National Institute of Neurological Disorders and Stroke rt-PA Stroke Study Group",
        "doi": "10.1056/NEJM199512143332401",
        "id": "ninds-1995",
        "pmid": "7477192",
        "source": "N Engl J Med. 1995;333(24):1581-1587",
        "title": "Tissue plasminogen activator for acute ischemic stroke"
      },
      "formula": "alteplase_stroke",
      "formula_expression": "total_mg = min(0.9 * weight_kg, 90.0); bolus_mg = 0.10 * total_mg; infusion_mg = 0.90 * total_mg; infusion_minutes = 60",
      "weight_kg": 80.0,
      "bolus_mg": 7.2,
      "capped": false,
      "infusion_mg": 64.8,
      "infusion_minutes": 60,
      "total_mg": 72.0
    }
  ]
}
```

## Response fields

- `formula` (string): alteplase_stroke
- `formula_expression` (string): Exact NINDS 1995 expression
- `weight_kg` (number): Input weight in kg
- `total_mg` (number): Total alteplase milligrams, min(0.9 × weight_kg, 90), 1 decimal
- `bolus_mg` (number): 10 percent bolus milligrams, 1 decimal
- `infusion_mg` (number): Remainder milligrams over 60 minutes, 1 decimal
- `infusion_minutes` (integer): Infusion duration in minutes (60)
- `capped` (boolean): True when 0.9 × weight_kg exceeds 90 mg
- `citation` (object): NINDS 1995 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": "National Institute of Neurological Disorders and Stroke rt-PA Stroke Study Group",
    "doi": "10.1056/NEJM199512143332401",
    "id": "ninds-1995",
    "pmid": "7477192",
    "source": "N Engl J Med. 1995;333(24):1581-1587",
    "title": "Tissue plasminogen activator for acute ischemic stroke"
  },
  "formula": "alteplase_stroke",
  "formula_expression": "total_mg = min(0.9 * weight_kg, 90.0); bolus_mg = 0.10 * total_mg; infusion_mg = 0.90 * total_mg; infusion_minutes = 60",
  "weight_kg": 80.0,
  "bolus_mg": 7.2,
  "capped": false,
  "infusion_mg": 64.8,
  "infusion_minutes": 60,
  "total_mg": 72.0
}
```

## Errors

- HTTP 400 `invalid_alteplase`: Alteplase dose inputs must match the NINDS 1995 weight window from that trial protocol. 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

- [NIHSS](https://magentlab.com/docs/nihss) — Sum Brott 1989 NIH stroke scale points from 15 caller-assigned examination integers, including pupillary response and plantar reflex. Weaker-limb motor arm and leg. Does not apply later total-score severity bands.
- [LAMS](https://magentlab.com/docs/lams) — Sum Llanes 2004 LAMS points from caller-assigned facial droop, arm drift, and grip (LAPSS motor items).
- [ABCD2 score](https://magentlab.com/docs/abcd2) — 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.

- 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. 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.