Kidney · LIVE

Kt/V

Compute the Daugirdas 1993 second-generation logarithmic single-pool variable-volume Kt/V from pre- and post-dialysis BUN, session length, ultrafiltration volume, and post-dialysis weight.

LIVE $0.005 USDC GET /api/calc/kt_v

Markdown: /docs/kt-v.md · Canonical: https://magentlab.com/docs/kt-v

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

What it computes

Compute the Daugirdas 1993 second-generation logarithmic single-pool variable-volume Kt/V from pre- and post-dialysis BUN, session length, ultrafiltration volume, and post-dialysis weight.

When to use

When an agent needs the published 1993 logarithmic Kt/V and must not invent adequacy targets, substitute equilibrated eKt/V or stdKt/V, or compute a urea reduction ratio.

When not to use

• Not a medical device.
• Not a dialysis prescription.
• Daugirdas 1993 second-generation single-pool variable-volume Kt/V only. This is not equilibrated eKt/V, not stdKt/V, and not a urea-reduction-ratio tool.
• Does not assign KDOQI or other adequacy targets. Those cuts are not in Daugirdas 1993.
• Weight is post-dialysis body weight (W). magent does not estimate urea distribution volume.

Formula

Kt/V = -ln(R - 0.008 * t) + (4 - 3.5 * R) * UF / W

Citation

Title

Second generation logarithmic estimates of single-pool variable volume Kt/V: an analysis of error

Authors

Daugirdas JT

Source

J Am Soc Nephrol. 1993;4(5):1205-1213

DOI

10.1681/ASN.V451205

Worked example

Also searched as

• Kt/V
• Daugirdas Kt/V
• single-pool Kt/V
• spKt/V
• hemodialysis Kt/V
• variable-volume Kt/V
• Daugirdas 1993 Kt/V
• urea kinetic Kt/V

Try

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

/api/calc/kt_v?pre_bun_mg_dl=80&post_bun_mg_dl=24&session_hours=4&uf_l=2&weight_kg=70

Full URL: https://api.magentlab.com/api/calc/kt_v?pre_bun_mg_dl=80&post_bun_mg_dl=24&session_hours=4&uf_l=2&weight_kg=70

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/kt_v?pre_bun_mg_dl=80&post_bun_mg_dl=24&session_hours=4&uf_l=2&weight_kg=70"

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/kt_v 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": [
    {
      "post_bun_mg_dl": "24",
      "pre_bun_mg_dl": "80",
      "session_hours": "4",
      "uf_l": "2",
      "weight_kg": "70"
    },
    {
      "post_bun_mg_dl": "24",
      "pre_bun_mg_dl": "80",
      "session_hours": "4",
      "uf_l": "2",
      "weight_kg": "70"
    }
  ]
}

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/kt_v",
  "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": "Daugirdas JT",
        "doi": "10.1681/ASN.V451205",
        "id": "daugirdas-1993",
        "pmid": "8305648",
        "source": "J Am Soc Nephrol. 1993;4(5):1205-1213",
        "title": "Second generation logarithmic estimates of single-pool variable volume Kt/V: an analysis of error"
      },
      "formula": "daugirdas_1993",
      "formula_expression": "Kt/V = -ln(R - 0.008 * t) + (4 - 3.5 * R) * UF / W",
      "weight_kg": 70.0,
      "kt_v": 1.4,
      "post_bun_mg_dl": 24.0,
      "pre_bun_mg_dl": 80.0,
      "session_hours": 4.0,
      "uf_l": 2.0
    },
    {
      "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": "Daugirdas JT",
        "doi": "10.1681/ASN.V451205",
        "id": "daugirdas-1993",
        "pmid": "8305648",
        "source": "J Am Soc Nephrol. 1993;4(5):1205-1213",
        "title": "Second generation logarithmic estimates of single-pool variable volume Kt/V: an analysis of error"
      },
      "formula": "daugirdas_1993",
      "formula_expression": "Kt/V = -ln(R - 0.008 * t) + (4 - 3.5 * R) * UF / W",
      "weight_kg": 70.0,
      "kt_v": 1.4,
      "post_bun_mg_dl": 24.0,
      "pre_bun_mg_dl": 80.0,
      "session_hours": 4.0,
      "uf_l": 2.0
    }
  ]
}

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": "Daugirdas JT",
    "doi": "10.1681/ASN.V451205",
    "id": "daugirdas-1993",
    "pmid": "8305648",
    "source": "J Am Soc Nephrol. 1993;4(5):1205-1213",
    "title": "Second generation logarithmic estimates of single-pool variable volume Kt/V: an analysis of error"
  },
  "formula": "daugirdas_1993",
  "formula_expression": "Kt/V = -ln(R - 0.008 * t) + (4 - 3.5 * R) * UF / W",
  "weight_kg": 70.0,
  "kt_v": 1.4,
  "post_bun_mg_dl": 24.0,
  "pre_bun_mg_dl": 80.0,
  "session_hours": 4.0,
  "uf_l": 2.0
}

Client errors (HTTP 400)

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

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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.
• 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.