# AKIN staging

AKIN

Status: LIVE
Price: $0.005 USDC
`GET /api/calc/akin`
HTML: https://magentlab.com/docs/akin
Markdown: https://magentlab.com/docs/akin.md

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

## What it computes

Apply Mehta 2007 Table 2 AKIN staging and return stage 0-3 as the worse of the creatinine and urine-output limbs, with initiated renal replacement therapy mapping to stage 3.

## When to use

When an agent already has baseline and current serum creatinine in mg/dL and a caller-assigned AKIN urine-output category (or an RRT flag) and needs the published AKIN stage. magent does not assay creatinine or measure urine. Not KDIGO 2012 and not RIFLE.

## When not to use

- Not a medical device and not a diagnosis of acute kidney injury.
- magent does not assay creatinine or measure urine. baseline_creatinine_mg_dl and current_creatinine_mg_dl are caller-supplied in mg/dL only.
- urine_output is the caller-assigned published duration category. magent does not collect weight or urine volume.
- The 48-hour window in Mehta 2007 is caller-applied; magent does not collect observation time.
- This tool is Mehta 2007 Table 2 AKIN staging only. Not KDIGO 2012 and not RIFLE. It does not report mortality bands.

## Formula

```
AKIN stage = max(creatinine_stage, urine_stage); RRT maps to stage 3. Creatinine vs baseline (unrounded mg/dL): stage 1 if increase ≥0.3 mg/dL or ratio 1.5–2.0; stage 2 if ratio >2.0 and ≤3.0; stage 3 if ratio >3.0 or (current ≥4.0 mg/dL and increase ≥0.5 mg/dL). Urine (caller-assigned): none → 0; oliguria_gt_6h → 1; oliguria_gt_12h → 2; oliguria_24h_or_anuria_12h → 3. Stage 0 if neither criterion and RRT is false (Mehta 2007 Table 2)
```

## Citation

[Acute Kidney Injury Network: report of an initiative to improve outcomes in acute kidney injury](https://doi.org/10.1186/cc5713)
Mehta RL, Kellum JA, Shah SV, et al
Crit Care. 2007;11(2):R31
DOI: [10.1186/cc5713](https://doi.org/10.1186/cc5713)

## Worked example

### No AKI: creatinine unchanged, no oliguria, no RRT

Given: `baseline_creatinine_mg_dl=1.0, current_creatinine_mg_dl=1.0, rrt=false, urine_output=none`

1. baseline 1.0 mg/dL and current 1.0 mg/dL: increase 0, ratio 1.0 → creat_stage 0
2. urine_output none → uo_stage 0
3. rrt false → stage = max(0, 0) = 0


## Also searched as

- AKIN
- AKIN staging
- Acute Kidney Injury Network
- AKIN creatinine stage
- Mehta 2007 AKI
- AKIN urine output
- AKIN RRT stage 3
- acute kidney injury stage

## Parameters

- `baseline_creatinine_mg_dl` (number, required): Baseline serum creatinine in mg/dL (0.1-20). Staging uses the unrounded value. µmol/L is not accepted on this tool. magent does not assay creatinine.
- `current_creatinine_mg_dl` (number, required): Current serum creatinine in mg/dL (0.1-20). Staging uses the unrounded value. µmol/L is not accepted on this tool. magent does not assay creatinine.
- `urine_output` (string, required): Caller-assigned AKIN urine-output category (Mehta 2007 Table 2): none (no oliguria or anuria criterion); oliguria_gt_6h (<0.5 mL/kg/h for >6 hours); oliguria_gt_12h (<0.5 mL/kg/h for >12 hours); oliguria_24h_or_anuria_12h (<0.3 mL/kg/h for 24 hours or anuria for 12 hours). Case-insensitive. magent does not collect weight or measure urine.
- `rrt` (boolean, required): Renal replacement therapy initiated as assigned by the caller. true maps to AKIN stage 3 irrespective of creatinine or urine stage (Mehta 2007). true or false.

## 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.

Method: `POST /api/calc/akin`
Max items: 25
Price: unit_amount + extra_item_amount * (n - 1) (unit 5000 atomic, extra 2000 atomic)
Status: 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:

```json
{
  "items": [
    {
      "baseline_creatinine_mg_dl": "1.0",
      "current_creatinine_mg_dl": "1.0",
      "rrt": "false",
      "urine_output": "none"
    },
    {
      "baseline_creatinine_mg_dl": "1.0",
      "current_creatinine_mg_dl": "1.0",
      "rrt": "false",
      "urine_output": "none"
    }
  ]
}
```

Human paywall (two-item fixture): https://api.magentlab.com/paywall/bulk/akin

Example 200:

```json
{
  "count": 2,
  "path": "/api/calc/akin",
  "items": [
    {
      "components": [
        {
          "value": 0,
          "factor": "creat_stage",
          "met": false
        },
        {
          "value": 0,
          "factor": "uo_stage",
          "met": false
        }
      ],
      "stage": 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": "Mehta RL, Kellum JA, Shah SV, et al",
        "doi": "10.1186/cc5713",
        "id": "mehta-2007",
        "pmid": "17331245",
        "source": "Crit Care. 2007;11(2):R31",
        "title": "Acute Kidney Injury Network: report of an initiative to improve outcomes in acute kidney injury"
      },
      "formula": "akin",
      "formula_expression": "AKIN stage = max(creatinine_stage, urine_stage); RRT maps to stage 3. Creatinine vs baseline (unrounded mg/dL): stage 1 if increase ≥0.3 mg/dL or ratio 1.5–2.0; stage 2 if ratio >2.0 and ≤3.0; stage 3 if ratio >3.0 or (current ≥4.0 mg/dL and increase ≥0.5 mg/dL). Urine (caller-assigned): none → 0; oliguria_gt_6h → 1; oliguria_gt_12h → 2; oliguria_24h_or_anuria_12h → 3. Stage 0 if neither criterion and RRT is false (Mehta 2007 Table 2)",
      "baseline_creatinine_mg_dl": 1.0,
      "creat_stage": 0,
      "current_creatinine_mg_dl": 1.0,
      "rrt": false,
      "uo_stage": 0,
      "urine_output": "none"
    },
    {
      "components": [
        {
          "value": 0,
          "factor": "creat_stage",
          "met": false
        },
        {
          "value": 0,
          "factor": "uo_stage",
          "met": false
        }
      ],
      "stage": 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": "Mehta RL, Kellum JA, Shah SV, et al",
        "doi": "10.1186/cc5713",
        "id": "mehta-2007",
        "pmid": "17331245",
        "source": "Crit Care. 2007;11(2):R31",
        "title": "Acute Kidney Injury Network: report of an initiative to improve outcomes in acute kidney injury"
      },
      "formula": "akin",
      "formula_expression": "AKIN stage = max(creatinine_stage, urine_stage); RRT maps to stage 3. Creatinine vs baseline (unrounded mg/dL): stage 1 if increase ≥0.3 mg/dL or ratio 1.5–2.0; stage 2 if ratio >2.0 and ≤3.0; stage 3 if ratio >3.0 or (current ≥4.0 mg/dL and increase ≥0.5 mg/dL). Urine (caller-assigned): none → 0; oliguria_gt_6h → 1; oliguria_gt_12h → 2; oliguria_24h_or_anuria_12h → 3. Stage 0 if neither criterion and RRT is false (Mehta 2007 Table 2)",
      "baseline_creatinine_mg_dl": 1.0,
      "creat_stage": 0,
      "current_creatinine_mg_dl": 1.0,
      "rrt": false,
      "uo_stage": 0,
      "urine_output": "none"
    }
  ]
}
```

## Response fields

- `formula` (string): akin
- `formula_expression` (string): Published Mehta 2007 Table 2 AKIN staging rule
- `baseline_creatinine_mg_dl` (number): Echo of baseline creatinine in mg/dL
- `current_creatinine_mg_dl` (number): Echo of current creatinine in mg/dL
- `urine_output` (string): Canonical urine-output token: none, oliguria_gt_6h, oliguria_gt_12h, or oliguria_24h_or_anuria_12h
- `rrt` (boolean): Echo of the caller-assigned RRT flag
- `creat_stage` (integer): AKIN creatinine limb stage 0-3 before RRT override
- `uo_stage` (integer): AKIN urine-output limb stage 0-3 before RRT override
- `stage` (integer): Final AKIN stage 0-3: max(creat_stage, uo_stage), or 3 when rrt is true. 0 is no AKI by AKIN. Not a diagnosis.
- `components` (array): Rows for creat_stage and uo_stage with factor, met, and value (the limb stage)
- `citation` (object): Mehta 2007 Crit Care citation
- `disclaimer` (string): Not-a-device notice

## Example JSON

Frozen fixture. Not a live lookup.

```json
{
  "components": [
    {
      "value": 0,
      "factor": "creat_stage",
      "met": false
    },
    {
      "value": 0,
      "factor": "uo_stage",
      "met": false
    }
  ],
  "stage": 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": "Mehta RL, Kellum JA, Shah SV, et al",
    "doi": "10.1186/cc5713",
    "id": "mehta-2007",
    "pmid": "17331245",
    "source": "Crit Care. 2007;11(2):R31",
    "title": "Acute Kidney Injury Network: report of an initiative to improve outcomes in acute kidney injury"
  },
  "formula": "akin",
  "formula_expression": "AKIN stage = max(creatinine_stage, urine_stage); RRT maps to stage 3. Creatinine vs baseline (unrounded mg/dL): stage 1 if increase ≥0.3 mg/dL or ratio 1.5–2.0; stage 2 if ratio >2.0 and ≤3.0; stage 3 if ratio >3.0 or (current ≥4.0 mg/dL and increase ≥0.5 mg/dL). Urine (caller-assigned): none → 0; oliguria_gt_6h → 1; oliguria_gt_12h → 2; oliguria_24h_or_anuria_12h → 3. Stage 0 if neither criterion and RRT is false (Mehta 2007 Table 2)",
  "baseline_creatinine_mg_dl": 1.0,
  "creat_stage": 0,
  "current_creatinine_mg_dl": 1.0,
  "rrt": false,
  "uo_stage": 0,
  "urine_output": "none"
}
```

## Errors

- HTTP 400 `invalid_creatinine`: creatinine_mg_dl (0.1-20) or creatinine_umol_l (9-1768) is required Returned before settlement; you are not charged.
- HTTP 400 `invalid_flag`: boolean clinical flags must be true or false Returned before settlement; you are not charged.
- HTTP 400 `invalid_akin`: each AKIN 2007 staging input must be a published value for that field. Returned before settlement; you are not charged.
- HTTP 400 `invalid_items`: POST body must be a JSON object with only an items array Returned before settlement; you are not charged.
- HTTP 400 `invalid_item_count`: items must be an array of 1 to 25 objects Returned before settlement; you are not charged.
- HTTP 400 `invalid_item`: each items entry must be a JSON object Returned before settlement; you are not charged.

Shared HTTP 402 and 503: https://magentlab.com/docs/payments

## Related tools

- [Cockcroft–Gault CrCl](https://magentlab.com/docs/crcl) — Compute Cockcroft–Gault creatinine clearance in mL/min using total body weight.

## 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.

- GET the tool with Accept: application/json (do not send Accept: text/html unless you want the human paywall).
- HTTP 402 means you have not paid. Decode the base64 PAYMENT-REQUIRED header. HTTP 503 is not a new quote.
- Sign accepts[0] (exact, EIP-3009) with validBefore = now + maxTimeoutSeconds (600 seconds), or accepts[1] (batch-settlement deposit/voucher) on product GET. Ping and POST {items} stay exact. Magent retries transient facilitator 429/5xx before answering.
- Retry the same URL with PAYMENT-SIGNATURE (base64 JSON of accepted and payload). Magent attaches canonical extensions.bazaar on CDP verify/settle; echoing 402 bazaar is optional.
- Success is HTTP 200 JSON plus PAYMENT-RESPONSE. exact settles before the tool. batch-settlement verifies (and deposit-settles) before the tool and commits the charge after HTTP 2xx. HTTP 503: retry the same PAYMENT-SIGNATURE. Mint a new exact nonce only after a new HTTP 402.

- offered `exact` on eip155:8453: Fixed-price USDC on Base. The buyer authorizes the advertised amount (EIP-3009). magent settles before the tool runs (paymentFlow upfront). extra.assetTransferMethod=eip3009 extra.paymentFlow=upfront.
- offered `batch-settlement` on eip155:8453: Payment-channel vouchers claimed later in batches. Exact stays accepts[0]. Same-path POST {items} is still exact. extra.assetTransferMethod=eip3009 extra.paymentFlow=authorization.

- not offered `upto`: Not offered. Usage-based: buyer authorizes a ceiling, seller settles the actual amount after work. Reserved for a future metered tool. Not for current calculators or code search.

Same-path POST {items} is still scheme exact: one EIP-3009 authorization for GET unit plus $0.002 per extra item. That is not x402 batch-settlement (payment channels / vouchers).

Shared HTTP 402 and 503 table: https://magentlab.com/docs/payments

Stdio MCP (one process per host): https://magentlab.com/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.