MAGENT

Neonatal · LIVE

Intrauterine RBC transfusion volume

Compute Mandelbrot 1988 intrauterine RBC transfusion volume from caller-assigned estimated fetal weight and initial, target, and donor hematocrits. Hematocrit arm only.

LIVE $0.005 USDC GET /api/calc/intrauterine_rbc

Markdown: /docs/intrauterine-rbc.md · Canonical: https://magentlab.com/docs/intrauterine-rbc

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

What it computes

Compute Mandelbrot 1988 intrauterine RBC transfusion volume from caller-assigned estimated fetal weight and initial, target, and donor hematocrits. Hematocrit arm only.

When to use

When an agent already has estimated fetal weight and hematocrits and needs the published Mandelbrot 1988 hematocrit-arm volume, not a platelet intrauterine transfusion, a biometry-derived weight, or a transfusion order.

When not to use

  • Not a medical device. Not a transfusion order.
  • Hematocrit arm only. Mandelbrot 1988 also allowed a platelet-count variant; magent does not implement platelets.
  • magent does not estimate fetal weight from biometry. estimated_fetal_weight_g is caller-assigned.

Formula

fetoplacental_volume_ml = 1.046 + estimated_fetal_weight_g * 0.14; volume_ml = fetoplacental_volume_ml * (hct_final_percent - hct_initial_percent) / hct_donor_percent

Citation

Title
Assessment of fetal blood volume for computer-assisted management of in utero transfusion
Authors
Mandelbrot L, Daffos F, Forestier F, MacAleese J, Descombey D
Source
Fetal Ther. 1988;3(1-2):60-66
DOI
10.1159/000263335

Worked example

EFW 1000 g, hematocrit 20 to 40, donor 80

Given: estimated_fetal_weight_g=1000hct_donor_percent=80hct_final_percent=40hct_initial_percent=20

  1. fetoplacental_volume_ml = 1.046 + 1000 * 0.14 = 141.046 → 141.0
  2. volume_ml = 141.046 * (40 - 20) / 80 = 35.2615 → 35.3

EFW 2500 g, hematocrit 20 to 40, donor 80

Given: estimated_fetal_weight_g=2500hct_donor_percent=80hct_final_percent=40hct_initial_percent=20

  1. fetoplacental_volume_ml = 1.046 + 2500 * 0.14 = 351.046 → 351.0
  2. volume_ml = 351.046 * (40 - 20) / 80 = 87.7615 → 87.8

Also searched as

  • intrauterine RBC transfusion
  • intrauterine transfusion volume
  • Mandelbrot fetal transfusion
  • IUT hematocrit
  • fetoplacental volume
  • in utero transfusion volume
  • fetal RBC transfusion volume

Try

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

/api/calc/intrauterine_rbc?estimated_fetal_weight_g=1000&hct_initial_percent=20&hct_final_percent=40&hct_donor_percent=80

Full URL: https://api.magentlab.com/api/calc/intrauterine_rbc?estimated_fetal_weight_g=1000&hct_initial_percent=20&hct_final_percent=40&hct_donor_percent=80

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/intrauterine_rbc?estimated_fetal_weight_g=1000&hct_initial_percent=20&hct_final_percent=40&hct_donor_percent=80"

Parameters

Name Type Required Description
estimated_fetal_weight_g number required Caller-assigned estimated fetal weight in grams (200-4000). Required. magent does not estimate fetal weight from biometry.
hct_initial_percent number required Initial fetal hematocrit as a percent (5-50). Must be strictly less than hct_final_percent.
hct_final_percent number required Target fetal hematocrit as a percent (20-60). Must be strictly greater than hct_initial_percent and strictly less than hct_donor_percent.
hct_donor_percent number required Donor unit hematocrit as a percent (60-90). Must be strictly greater than hct_final_percent.

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/intrauterine_rbc 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": [
    {
      "estimated_fetal_weight_g": "1000",
      "hct_donor_percent": "80",
      "hct_final_percent": "40",
      "hct_initial_percent": "20"
    },
    {
      "estimated_fetal_weight_g": "1000",
      "hct_donor_percent": "80",
      "hct_final_percent": "40",
      "hct_initial_percent": "20"
    }
  ]
}

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/intrauterine_rbc",
  "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": "Mandelbrot L, Daffos F, Forestier F, MacAleese J, Descombey D",
        "doi": "10.1159/000263335",
        "id": "mandelbrot-1988",
        "pmid": "3257068",
        "source": "Fetal Ther. 1988;3(1-2):60-66",
        "title": "Assessment of fetal blood volume for computer-assisted management of in utero transfusion"
      },
      "formula": "mandelbrot_hct",
      "formula_expression": "fetoplacental_volume_ml = 1.046 + estimated_fetal_weight_g * 0.14; volume_ml = fetoplacental_volume_ml * (hct_final_percent - hct_initial_percent) / hct_donor_percent",
      "volume_ml": 35.3,
      "hct_initial_percent": 20.0,
      "estimated_fetal_weight_g": 1.0e3,
      "fetoplacental_volume_ml": 141.0,
      "hct_donor_percent": 80.0,
      "hct_final_percent": 40.0
    },
    {
      "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": "Mandelbrot L, Daffos F, Forestier F, MacAleese J, Descombey D",
        "doi": "10.1159/000263335",
        "id": "mandelbrot-1988",
        "pmid": "3257068",
        "source": "Fetal Ther. 1988;3(1-2):60-66",
        "title": "Assessment of fetal blood volume for computer-assisted management of in utero transfusion"
      },
      "formula": "mandelbrot_hct",
      "formula_expression": "fetoplacental_volume_ml = 1.046 + estimated_fetal_weight_g * 0.14; volume_ml = fetoplacental_volume_ml * (hct_final_percent - hct_initial_percent) / hct_donor_percent",
      "volume_ml": 35.3,
      "hct_initial_percent": 20.0,
      "estimated_fetal_weight_g": 1.0e3,
      "fetoplacental_volume_ml": 141.0,
      "hct_donor_percent": 80.0,
      "hct_final_percent": 40.0
    }
  ]
}

Response

Field Type Description
formula string mandelbrot_hct
formula_expression string Exact expression used
estimated_fetal_weight_g number Caller-assigned estimated fetal weight in grams
hct_initial_percent number Initial fetal hematocrit percent used
hct_final_percent number Target fetal hematocrit percent used
hct_donor_percent number Donor unit hematocrit percent used
fetoplacental_volume_ml number Mandelbrot 1988 fetoplacental volume in mL, 1 decimal
volume_ml number Intrauterine RBC transfusion volume in mL, 1 decimal
citation object Mandelbrot et al. Fetal Ther 1988 citation
disclaimer string Not-a-device notice

Example JSON

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

{
  "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": "Mandelbrot L, Daffos F, Forestier F, MacAleese J, Descombey D",
    "doi": "10.1159/000263335",
    "id": "mandelbrot-1988",
    "pmid": "3257068",
    "source": "Fetal Ther. 1988;3(1-2):60-66",
    "title": "Assessment of fetal blood volume for computer-assisted management of in utero transfusion"
  },
  "formula": "mandelbrot_hct",
  "formula_expression": "fetoplacental_volume_ml = 1.046 + estimated_fetal_weight_g * 0.14; volume_ml = fetoplacental_volume_ml * (hct_final_percent - hct_initial_percent) / hct_donor_percent",
  "volume_ml": 35.3,
  "hct_initial_percent": 20.0,
  "estimated_fetal_weight_g": 1.0e3,
  "fetoplacental_volume_ml": 141.0,
  "hct_donor_percent": 80.0,
  "hct_final_percent": 40.0
}

Client errors (HTTP 400)

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

HTTP Code When
400 invalid_iut Intrauterine transfusion inputs must match Mandelbrot 1988 estimated fetal weight and hematocrit window from that paper. 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

  • RhIG vials — Compute ACOG Practice Bulletin 181 RhD immune globulin vial count from caller-assigned fetal-cell percent and maternal blood volume using AABB Technical Manual rounding of FMH/30.
  • Plasma starting dose — Compute the BSH Green 2018 starting plasma volume from body weight: 15 mL/kg in the absence of major bleeding. Adult starting dose only.
  • Neonatal partial-exchange volume — Compute the Kumar 2004 partial-exchange transfusion volume from actual hematocrit and caller-assigned blood volume, using the trial's printed desired hematocrit of 55 percent.

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.