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Martin estimated LDL-C

Martin LDL-C

Estimate LDL-C from total cholesterol, HDL, and triglycerides using Martin 2013: non-HDL-C minus triglycerides divided by the published 180-cell TG:VLDL-C factor (mg/dL).

LIVE $0.005 USDC GET /api/calc/martin_ldl

Markdown: /docs/martin-ldl.md · Canonical: https://magentlab.com/docs/martin-ldl

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

What it computes

Estimate LDL-C from total cholesterol, HDL, and triglycerides using Martin 2013: non-HDL-C minus triglycerides divided by the published 180-cell TG:VLDL-C factor (mg/dL).

When to use

When an agent needs Martin 2013 LDL arithmetic from a standard lipid panel in mg/dL and must not apply Friedewald TG/5 or Sampson 2020.

When not to use

  • Not a medical device, not a diagnosis, and not a statin order. Direct LDL assay is out of scope.
  • mg/dL only. magent does not convert mmol/L.
  • Not Friedewald (fixed factor 5) and not Sampson 2020.
  • Triglycerides below 7 or at 400 mg/dL or higher are rejected. The table's first TG row starts at 7; the paper's primary concordance analysis is triglycerides lower than 400 mg/dL.
  • The paper notes remaining TG:VLDL-C variance unexplained by the standard lipid profile, and limited performance in severe hypertriglyceridemia and type III Fredrickson-Levy dyslipidemia.

Formula

ldl_c_mg_dl = (total_cholesterol_mg_dl - hdl_mg_dl) - (triglycerides_mg_dl / factor); factor is the Martin 2013 180-cell median TG:VLDL-C ratio by non-HDL-C and TG strata (mg/dL); not Friedewald factor 5

Citation

Title
Comparison of a novel method vs the Friedewald equation for estimating low-density lipoprotein cholesterol
Authors
Martin SS, Blaha MJ, Elshazly MB, et al.
Source
JAMA. 2013;310(19):2061-2068
DOI
10.1001/jama.2013.280532

Worked example

TC 200, HDL 50, TG 150 mg/dL

Given: hdl_mg_dl=50total_cholesterol_mg_dl=200triglycerides_mg_dl=150

  1. non-HDL-C = 200 - 50 = 150 mg/dL (non-HDL-C stratum 130-159)
  2. TG 150 mg/dL is TG stratum 147-154; Martin 2013 factor = 5.7
  3. LDL-C = 150 - (150 / 5.7) = 123.7 mg/dL

Also searched as

  • Martin equation LDL
  • Martin 2013 LDL-C
  • adjustable factor LDL
  • TG VLDL-C ratio table
  • novel method vs Friedewald
  • estimated LDL cholesterol Martin

Try

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

/api/calc/martin_ldl?total_cholesterol_mg_dl=200&hdl_mg_dl=50&triglycerides_mg_dl=150

Full URL: https://api.magentlab.com/api/calc/martin_ldl?total_cholesterol_mg_dl=200&hdl_mg_dl=50&triglycerides_mg_dl=150

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/martin_ldl?total_cholesterol_mg_dl=200&hdl_mg_dl=50&triglycerides_mg_dl=150"

Parameters

Name Type Required Description
total_cholesterol_mg_dl number required Total cholesterol in mg/dL (50-500). mg/dL only; magent does not convert mmol/L.
hdl_mg_dl number required HDL cholesterol in mg/dL (5-150). Must be less than total cholesterol so non-HDL-C is positive.
triglycerides_mg_dl number required Triglycerides in mg/dL (7-399). The Martin 2013 table first TG row starts at 7. Values of 400 or higher are rejected; that is the paper's primary analysis cut.

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/martin_ldl 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": [
    {
      "hdl_mg_dl": "50",
      "total_cholesterol_mg_dl": "200",
      "triglycerides_mg_dl": "150"
    },
    {
      "hdl_mg_dl": "50",
      "total_cholesterol_mg_dl": "200",
      "triglycerides_mg_dl": "150"
    }
  ]
}

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/martin_ldl",
  "items": [
    {
      "factor": 5.7,
      "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": "Martin SS, Blaha MJ, Elshazly MB, et al.",
        "doi": "10.1001/jama.2013.280532",
        "id": "martin-2013",
        "pmid": "24240933",
        "source": "JAMA. 2013;310(19):2061-2068",
        "title": "Comparison of a novel method vs the Friedewald equation for estimating low-density lipoprotein cholesterol"
      },
      "formula": "martin",
      "formula_expression": "ldl_c_mg_dl = (total_cholesterol_mg_dl - hdl_mg_dl) - (triglycerides_mg_dl / factor); factor is the Martin 2013 180-cell median TG:VLDL-C ratio by non-HDL-C and TG strata (mg/dL); not Friedewald factor 5",
      "hdl_mg_dl": 50.0,
      "triglycerides_mg_dl": 150.0,
      "total_cholesterol_mg_dl": 200.0,
      "ldl_c_mg_dl": 123.7,
      "non_hdl_c_mg_dl": 150.0
    },
    {
      "factor": 5.7,
      "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": "Martin SS, Blaha MJ, Elshazly MB, et al.",
        "doi": "10.1001/jama.2013.280532",
        "id": "martin-2013",
        "pmid": "24240933",
        "source": "JAMA. 2013;310(19):2061-2068",
        "title": "Comparison of a novel method vs the Friedewald equation for estimating low-density lipoprotein cholesterol"
      },
      "formula": "martin",
      "formula_expression": "ldl_c_mg_dl = (total_cholesterol_mg_dl - hdl_mg_dl) - (triglycerides_mg_dl / factor); factor is the Martin 2013 180-cell median TG:VLDL-C ratio by non-HDL-C and TG strata (mg/dL); not Friedewald factor 5",
      "hdl_mg_dl": 50.0,
      "triglycerides_mg_dl": 150.0,
      "total_cholesterol_mg_dl": 200.0,
      "ldl_c_mg_dl": 123.7,
      "non_hdl_c_mg_dl": 150.0
    }
  ]
}

Response

Field Type Description
formula string martin
formula_expression string Martin 2013 expression with table factor
total_cholesterol_mg_dl number Input total cholesterol in mg/dL
hdl_mg_dl number Input HDL cholesterol in mg/dL
triglycerides_mg_dl number Input triglycerides in mg/dL
non_hdl_c_mg_dl number Total cholesterol minus HDL, 1 decimal
factor number Martin 2013 180-cell TG:VLDL-C median for the specimen's strata
ldl_c_mg_dl number Estimated LDL-C in mg/dL, 1 decimal
citation object Martin JAMA 2013 citation
disclaimer string Not-a-device notice

Example JSON

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

{
  "factor": 5.7,
  "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": "Martin SS, Blaha MJ, Elshazly MB, et al.",
    "doi": "10.1001/jama.2013.280532",
    "id": "martin-2013",
    "pmid": "24240933",
    "source": "JAMA. 2013;310(19):2061-2068",
    "title": "Comparison of a novel method vs the Friedewald equation for estimating low-density lipoprotein cholesterol"
  },
  "formula": "martin",
  "formula_expression": "ldl_c_mg_dl = (total_cholesterol_mg_dl - hdl_mg_dl) - (triglycerides_mg_dl / factor); factor is the Martin 2013 180-cell median TG:VLDL-C ratio by non-HDL-C and TG strata (mg/dL); not Friedewald factor 5",
  "hdl_mg_dl": 50.0,
  "triglycerides_mg_dl": 150.0,
  "total_cholesterol_mg_dl": 200.0,
  "ldl_c_mg_dl": 123.7,
  "non_hdl_c_mg_dl": 150.0
}

Client errors (HTTP 400)

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

HTTP Code When
400 invalid_martin_ldl Martin LDL-C needs total cholesterol, HDL, and triglycerides in published mg/dL ranges (Martin 2013). 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

  • Friedewald LDL-C — Estimate LDL-C from total cholesterol, HDL, and triglycerides using Friedewald 1972.
  • Sampson LDL-C — Estimate LDL-C from total cholesterol, HDL, and triglycerides using Sampson 2020.

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.