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4Ts score

Compute the Lo 2006 4Ts score as the sum of four caller-assigned integers 0-2 (thrombocytopenia, timing, thrombosis, other causes).

LIVE $0.005 USDC GET /api/calc/four_ts

Markdown: /docs/four-ts.md · Canonical: https://magentlab.com/docs/four-ts

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

What it computes

Compute the Lo 2006 4Ts score as the sum of four caller-assigned integers 0-2 (thrombocytopenia, timing, thrombosis, other causes).

When to use

When an agent has already applied the Lo 2006 table and needs the published 4Ts total and pretest-probability band, not a HIT antibody result or HEP score.

When not to use

Not a diagnosis of HIT.
This is the 4Ts score (Lo 2006), not the HEP score and not a HIT antibody result.
thrombocytopenia, timing, thrombosis, and other_causes are caller-assigned integers 0-2 using the published Lo 2006 table. magent does not grade platelet counts or day of onset.
Bands 0-3 / 4-5 / 6-8 are pretest probability groups (low / intermediate / high), not an antibody result.

Formula

4Ts = thrombocytopenia + timing + thrombosis + other_causes; each 0-2 caller-assigned from Lo 2006 table; pretest probability low 0-3, intermediate 4-5, high 6-8; max 8

Citation

Title: Evaluation of pretest clinical score (4 T's) for the diagnosis of heparin-induced thrombocytopenia in two clinical settings
Authors: Lo GK, Juhl D, Warkentin TE, Sigouin CS, Eichler P, Greinacher A
Source: J Thromb Haemost. 2006;4(4):759-765
DOI: 10.1111/j.1538-7836.2006.01787.x

Worked example

All components 0

Given: other_causes=0thrombocytopenia=0thrombosis=0timing=0

thrombocytopenia 0; timing 0; thrombosis 0; other_causes 0
Score = 0; band 0-3 (low pretest probability)

Also searched as

4Ts score
4 T's HIT
four Ts heparin
HIT pretest 4Ts
Lo 2006 4Ts
heparin-induced thrombocytopenia 4Ts
4Ts thrombocytopenia score
oTher causes HIT score

Try

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

/api/calc/four_ts?thrombocytopenia=0&timing=0&thrombosis=0&other_causes=0

Full URL: https://api.magentlab.com/api/calc/four_ts?thrombocytopenia=0&timing=0&thrombosis=0&other_causes=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/four_ts?thrombocytopenia=0&timing=0&thrombosis=0&other_causes=0"

Parameters

Name	Type	Required	Description
`thrombocytopenia`	integer	required	Caller-assigned Lo 2006 thrombocytopenia points (0, 1, or 2). magent does not grade platelet counts. 2: platelet fall >50% AND nadir >=20. 1: fall 30-50% OR nadir 10-19. 0: fall <30% OR nadir <10.
`timing`	integer	required	Caller-assigned Lo 2006 timing points (0, 1, or 2). magent does not infer day of onset. 2: clear onset days 5-10, or <=1 day with prior heparin within 30 days. 1: consistent with days 5-10 but not clear; onset after day 10; or <=1 day with heparin 30-100 days ago. 0: fall too early without recent heparin.
`thrombosis`	integer	required	Caller-assigned Lo 2006 thrombosis points (0, 1, or 2). 2: new thrombosis, skin necrosis, or acute systemic reaction after heparin bolus. 1: progressive/recurrent thrombosis, silent thrombosis, or erythematous skin lesions. 0: none.
`other_causes`	integer	required	Caller-assigned Lo 2006 other (oTher) causes of thrombocytopenia (0, 1, or 2). More points = more HIT-like. 2: no other apparent cause. 1: possible other cause. 0: definite other cause.

Bulk (POST)

POST the same path with a JSON items array. Price is n times the GET unit. Invalid items return HTTP 400 before settlement.

POST /api/calc/four_ts Max 25 unit_amount * n PREVIEW

1 to 25 items. Each item uses the same keys as the GET query parameters.
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": [
    {
      "other_causes": "0",
      "thrombocytopenia": "0",
      "thrombosis": "0",
      "timing": "0"
    },
    {
      "other_causes": "0",
      "thrombocytopenia": "0",
      "thrombosis": "0",
      "timing": "0"
    }
  ]
}

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/four_ts",
  "items": [
    {
      "components": [
        {
          "value": 0,
          "factor": "thrombocytopenia",
          "points": 0,
          "present": false
        },
        {
          "value": 0,
          "factor": "timing",
          "points": 0,
          "present": false
        },
        {
          "value": 0,
          "factor": "thrombosis",
          "points": 0,
          "present": false
        },
        {
          "value": 0,
          "factor": "other_causes",
          "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": "Lo GK, Juhl D, Warkentin TE, Sigouin CS, Eichler P, Greinacher A",
        "doi": "10.1111/j.1538-7836.2006.01787.x",
        "id": "lo-2006",
        "source": "J Thromb Haemost. 2006;4(4):759-765",
        "title": "Evaluation of pretest clinical score (4 T's) for the diagnosis of heparin-induced thrombocytopenia in two clinical settings"
      },
      "formula": "four_ts",
      "formula_expression": "4Ts = thrombocytopenia + timing + thrombosis + other_causes; each 0-2 caller-assigned from Lo 2006 table; pretest probability low 0-3, intermediate 4-5, high 6-8; max 8",
      "max_score": 8,
      "score": 0,
      "four_ts_band": "0-3"
    },
    {
      "components": [
        {
          "value": 0,
          "factor": "thrombocytopenia",
          "points": 0,
          "present": false
        },
        {
          "value": 0,
          "factor": "timing",
          "points": 0,
          "present": false
        },
        {
          "value": 0,
          "factor": "thrombosis",
          "points": 0,
          "present": false
        },
        {
          "value": 0,
          "factor": "other_causes",
          "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": "Lo GK, Juhl D, Warkentin TE, Sigouin CS, Eichler P, Greinacher A",
        "doi": "10.1111/j.1538-7836.2006.01787.x",
        "id": "lo-2006",
        "source": "J Thromb Haemost. 2006;4(4):759-765",
        "title": "Evaluation of pretest clinical score (4 T's) for the diagnosis of heparin-induced thrombocytopenia in two clinical settings"
      },
      "formula": "four_ts",
      "formula_expression": "4Ts = thrombocytopenia + timing + thrombosis + other_causes; each 0-2 caller-assigned from Lo 2006 table; pretest probability low 0-3, intermediate 4-5, high 6-8; max 8",
      "max_score": 8,
      "score": 0,
      "four_ts_band": "0-3"
    }
  ]
}

Response

Field	Type	Description
`formula`	string	four_ts
`formula_expression`	string	Exact expression used
`score`	integer	Total points 0-8
`max_score`	integer	Always 8
`four_ts_band`	string	0-3, 4-5, or 6-8 (Lo 2006 pretest probability groups)
`components`	array	Per-factor 0-2 points
`citation`	object	Lo 2006 citation
`disclaimer`	string	Not-a-device notice

Example JSON

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

{
  "components": [
    {
      "value": 0,
      "factor": "thrombocytopenia",
      "points": 0,
      "present": false
    },
    {
      "value": 0,
      "factor": "timing",
      "points": 0,
      "present": false
    },
    {
      "value": 0,
      "factor": "thrombosis",
      "points": 0,
      "present": false
    },
    {
      "value": 0,
      "factor": "other_causes",
      "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": "Lo GK, Juhl D, Warkentin TE, Sigouin CS, Eichler P, Greinacher A",
    "doi": "10.1111/j.1538-7836.2006.01787.x",
    "id": "lo-2006",
    "source": "J Thromb Haemost. 2006;4(4):759-765",
    "title": "Evaluation of pretest clinical score (4 T's) for the diagnosis of heparin-induced thrombocytopenia in two clinical settings"
  },
  "formula": "four_ts",
  "formula_expression": "4Ts = thrombocytopenia + timing + thrombosis + other_causes; each 0-2 caller-assigned from Lo 2006 table; pretest probability low 0-3, intermediate 4-5, high 6-8; max 8",
  "max_score": 8,
  "score": 0,
  "four_ts_band": "0-3"
}

Client errors (HTTP 400)

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

HTTP	Code	When
400	`invalid_four_ts_component`	thrombocytopenia, timing, thrombosis, and other_causes must each be 0, 1, or 2. 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

ANC — Compute absolute neutrophil count from WBC and neutrophil plus band percents, plus a Bodey 1966 granulocyte band.

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. 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

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.