Fluids · LIVE

Net fluid balance (I/O)

Compute net fluid balance in mL as caller-assigned total intake minus total output over the same interval, with a positive, negative, or zero label from the sign of that difference.

LIVE $0.005 USDC GET /api/calc/fluid_io

Markdown: /docs/fluid-io.md · Canonical: https://magentlab.com/docs/fluid-io

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

What it computes

Compute net fluid balance in mL as caller-assigned total intake minus total output over the same interval, with a positive, negative, or zero label from the sign of that difference.

When to use

When an agent needs Acheampong 2015 net fluid balance (total intake minus total output) from caller-assigned volumes and must not invent insensible-loss estimates, a resuscitation bolus, or a diuretic order.

When not to use

• Not a medical device. Not a resuscitation or diuretic order. Not a fluid prescription.
• magent does not measure intake or output. Caller assigns volumes over the same interval.
• Does not estimate insensible losses (Acheampong 2015 excluded them as unreliable). Does not apply third-space coefficients or weight-based TBW.

Formula

net_balance_ml = total_intake_ml - total_output_ml

Citation

Title

A positive fluid balance is an independent prognostic factor in patients with sepsis

Authors

Acheampong A, Vincent JL

Source

Crit Care. 2015;19(1):251

DOI

10.1186/s13054-015-0970-1

Worked example

Also searched as

• net fluid balance
• I/O balance
• fluid intake output
• cumulative fluid balance
• Acheampong fluid balance
• daily fluid balance
• intake minus output

Try

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

/api/calc/fluid_io?total_intake_ml=2500&total_output_ml=1800

Full URL: https://api.magentlab.com/api/calc/fluid_io?total_intake_ml=2500&total_output_ml=1800

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/fluid_io?total_intake_ml=2500&total_output_ml=1800"

Parameters

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/fluid_io 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": [
    {
      "total_intake_ml": "2500",
      "total_output_ml": "1800"
    },
    {
      "total_intake_ml": "2500",
      "total_output_ml": "1800"
    }
  ]
}

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/fluid_io",
  "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": "Acheampong A, Vincent JL",
        "doi": "10.1186/s13054-015-0970-1",
        "id": "acheampong-2015",
        "pmid": "26073560",
        "source": "Crit Care. 2015;19(1):251",
        "title": "A positive fluid balance is an independent prognostic factor in patients with sepsis"
      },
      "formula": "acheampong_2015",
      "formula_expression": "net_balance_ml = total_intake_ml - total_output_ml",
      "balance_label": "positive",
      "net_balance_ml": 700,
      "total_intake_ml": 2500,
      "total_output_ml": 1800
    },
    {
      "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": "Acheampong A, Vincent JL",
        "doi": "10.1186/s13054-015-0970-1",
        "id": "acheampong-2015",
        "pmid": "26073560",
        "source": "Crit Care. 2015;19(1):251",
        "title": "A positive fluid balance is an independent prognostic factor in patients with sepsis"
      },
      "formula": "acheampong_2015",
      "formula_expression": "net_balance_ml = total_intake_ml - total_output_ml",
      "balance_label": "positive",
      "net_balance_ml": 700,
      "total_intake_ml": 2500,
      "total_output_ml": 1800
    }
  ]
}

Response

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": "Acheampong A, Vincent JL",
    "doi": "10.1186/s13054-015-0970-1",
    "id": "acheampong-2015",
    "pmid": "26073560",
    "source": "Crit Care. 2015;19(1):251",
    "title": "A positive fluid balance is an independent prognostic factor in patients with sepsis"
  },
  "formula": "acheampong_2015",
  "formula_expression": "net_balance_ml = total_intake_ml - total_output_ml",
  "balance_label": "positive",
  "net_balance_ml": 700,
  "total_intake_ml": 2500,
  "total_output_ml": 1800
}

Client errors (HTTP 400)

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

Related tools

• NICE adult IV maintenance — Compute NICE CG174 adult hospital routine maintenance water (20, 25, or 30 mL/kg/day), approximately 1 mmol/kg/day sodium, potassium, and chloride each, and the fixed 50–100 g/day glucose range.
• Parkland formula — Compute adult Parkland 24-hour crystalloid volume from weight and percent TBSA, with half allotted to the first 8 hours from the time of burn.
• Maintenance fluids — Compute Holliday–Segar 1957 daily maintenance water from weight, plus the corresponding hourly milliliters.

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.