# Age-adjusted D-dimer cutoff (ADJUST-PE)

Age-adjusted D-dimer cutoff

Status: LIVE
Price: $0.005 USDC
`GET /api/calc/age_adjusted_dimer`
HTML: https://magentlab.com/docs/age-adjusted-dimer
Markdown: https://magentlab.com/docs/age-adjusted-dimer.md

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

## What it computes

Apply the Righini 2014 ADJUST-PE age-adjusted D-dimer cutoff and return whether PE is excluded at the published FEU threshold.

## When to use

When an agent has caller-assigned age and a D-dimer in ng/mL FEU and needs the published PE-excluded or CTPA-indicated result.

## When not to use

- Not a diagnosis of pulmonary embolism or VTE. Age-adjusted D-dimer is a rule-out cutoff, not a PE confirmation.
- Not the YEARS algorithm and not the Wells PE score. Do not substitute those tools.
- D-dimer is ng/mL fibrinogen-equivalent units (FEU) only, not DDU. magent does not convert units.
- PE/VTE is excluded only when D-dimer is strictly below the age-adjusted cutoff: 500 ng/mL FEU when age < 50, or age × 10 when age ≥ 50. Equality is not excluded.
- The caller assigns age and D-dimer. magent does not examine the patient.

## Formula

```
PE excluded iff d_dimer_ng_ml < (500 if age < 50 else age * 10); D-dimer is ng/mL FEU; equality is not excluded
```

## Citation

[Age-adjusted D-dimer cutoff levels to rule out pulmonary embolism: the ADJUST-PE study](https://doi.org/10.1001/jama.2014.2135)
Righini M, Van Es J, Den Exter PL, et al.
JAMA. 2014;311(11):1117-1124
DOI: [10.1001/jama.2014.2135](https://doi.org/10.1001/jama.2014.2135)

## Worked example

### Age 40, D-dimer 499 ng/mL FEU

Given: `age=40, d_dimer_ng_ml=499`

1. Age 40 < 50 → threshold is 500 ng/mL FEU
2. 499 < 500 → PE excluded; CTPA not indicated


### Age 40, D-dimer equal to 500 is not excluded

Given: `age=40, d_dimer_ng_ml=500`

1. Age 40 < 50 so the threshold is 500
2. 500 is not < 500 → PE not excluded; CTPA indicated


## Also searched as

- age-adjusted D-dimer
- ADJUST-PE
- Righini D-dimer
- age adjusted dimer cutoff
- age-adjusted D-dimer PE
- ADJUST PE study

## Parameters

- `age` (integer, required): Age in years (18-120). Cutoff is 500 ng/mL FEU when age < 50; age × 10 when age ≥ 50 (age 50 → 500).
- `d_dimer_ng_ml` (number, required): D-dimer in ng/mL fibrinogen-equivalent units (FEU) as in Righini 2014 (0-20000). PE excluded only when strictly below the age-adjusted cutoff. Equality is not excluded. DDU and other units are not this tool.

## 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/age_adjusted_dimer`
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": "40",
      "d_dimer_ng_ml": "499"
    },
    {
      "age": "40",
      "d_dimer_ng_ml": "499"
    }
  ]
}
```

Human paywall (two-item fixture): https://api.magentlab.com/paywall/bulk/age-adjusted-dimer

Example 200:

```json
{
  "count": 2,
  "path": "/api/calc/age_adjusted_dimer",
  "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": "Righini M, Van Es J, Den Exter PL, et al.",
        "doi": "10.1001/jama.2014.2135",
        "id": "righini-2014",
        "source": "JAMA. 2014;311(11):1117-1124",
        "title": "Age-adjusted D-dimer cutoff levels to rule out pulmonary embolism: the ADJUST-PE study"
      },
      "formula": "age_adjusted_dimer",
      "formula_expression": "PE excluded iff d_dimer_ng_ml < (500 if age < 50 else age * 10); D-dimer is ng/mL FEU; equality is not excluded",
      "age_years": 40,
      "criteria": [
        {
          "value": 40,
          "factor": "age_ge_50",
          "met": false
        }
      ],
      "ctpa_indicated": false,
      "d_dimer_ng_ml": 499.0,
      "d_dimer_threshold_ng_ml": 500.0,
      "pe_excluded": true
    },
    {
      "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": "Righini M, Van Es J, Den Exter PL, et al.",
        "doi": "10.1001/jama.2014.2135",
        "id": "righini-2014",
        "source": "JAMA. 2014;311(11):1117-1124",
        "title": "Age-adjusted D-dimer cutoff levels to rule out pulmonary embolism: the ADJUST-PE study"
      },
      "formula": "age_adjusted_dimer",
      "formula_expression": "PE excluded iff d_dimer_ng_ml < (500 if age < 50 else age * 10); D-dimer is ng/mL FEU; equality is not excluded",
      "age_years": 40,
      "criteria": [
        {
          "value": 40,
          "factor": "age_ge_50",
          "met": false
        }
      ],
      "ctpa_indicated": false,
      "d_dimer_ng_ml": 499.0,
      "d_dimer_threshold_ng_ml": 500.0,
      "pe_excluded": true
    }
  ]
}
```

## Response fields

- `formula` (string): age_adjusted_dimer
- `formula_expression` (string): Age-adjusted D-dimer cutoff with a strict less-than FEU threshold
- `age_years` (integer): Caller age in years
- `d_dimer_ng_ml` (number): Caller D-dimer in ng/mL FEU
- `d_dimer_threshold_ng_ml` (number): 500.0 when age < 50; age × 10.0 when age ≥ 50
- `pe_excluded` (boolean): true only when D-dimer is strictly below the age-adjusted cutoff. Not a diagnosis.
- `ctpa_indicated` (boolean): true when PE is not excluded (not pe_excluded)
- `criteria` (array): age_ge_50 row with factor, met, and value (age)
- `citation` (object): Righini 2014 JAMA ADJUST-PE 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": "Righini M, Van Es J, Den Exter PL, et al.",
    "doi": "10.1001/jama.2014.2135",
    "id": "righini-2014",
    "source": "JAMA. 2014;311(11):1117-1124",
    "title": "Age-adjusted D-dimer cutoff levels to rule out pulmonary embolism: the ADJUST-PE study"
  },
  "formula": "age_adjusted_dimer",
  "formula_expression": "PE excluded iff d_dimer_ng_ml < (500 if age < 50 else age * 10); D-dimer is ng/mL FEU; equality is not excluded",
  "age_years": 40,
  "criteria": [
    {
      "value": 40,
      "factor": "age_ge_50",
      "met": false
    }
  ],
  "ctpa_indicated": false,
  "d_dimer_ng_ml": 499.0,
  "d_dimer_threshold_ng_ml": 500.0,
  "pe_excluded": true
}
```

## Errors

- HTTP 400 `invalid_age`: age must be an integer from 18 to 120 Returned before settlement; you are not charged.
- HTTP 400 `invalid_d_dimer`: d_dimer_ng_ml must be a number from 0 to 20000. 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

- [YEARS algorithm](https://magentlab.com/docs/years) — Apply the van der Hulle 2017 YEARS algorithm: count three caller-assigned items and return whether PE is excluded at the published D-dimer threshold.
- [PERC rule](https://magentlab.com/docs/perc) — Apply the Kline 2004 eight-factor pulmonary embolism rule-out criteria and return whether all eight are met (PERC-negative).

## Payment

Required query parameters must be present and valid. 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 EIP-3009 (scheme exact, assetTransferMethod eip3009) with validBefore = now + accepts[0].maxTimeoutSeconds (600 seconds). That window starts when you sign and must cover wallet confirmation plus CDP verify and settle. Magent retries transient facilitator 429/5xx before answering. Do not send upto or batch-settlement payloads; magent does not offer those schemes.
- Retry the same URL with PAYMENT-SIGNATURE (base64 JSON echoing accepted, payload, and extensions when present).
- Success is HTTP 200 JSON plus PAYMENT-RESPONSE. Settlement happens before the tool runs. HTTP 503 settlement_uncertain or settle_failed: retry the same PAYMENT-SIGNATURE. Mint a new 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.

- 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.
- not offered `batch-settlement`: Not offered. Payment-channel vouchers claimed later in batches. Not the same as POST {items} bulk (that is still exact).

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

- Invalid query parameters return HTTP 400 before settlement. You are not charged.
- Settlement finishes before the tool executes (paymentFlow upfront). 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.