# Corrected calcium

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

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

## What it computes

Compute Payne albumin-corrected calcium from total calcium and albumin.

## When to use

When an agent needs albumin-corrected calcium arithmetic and must not apply a guessed factor.

## When not to use

- Not a treatment recommendation and not an ionized-calcium substitute.
- Uses albumin 4.0 g/dL as the Payne reference. Does not accept ionized calcium or alternative coefficients.

## Formula

```
corrected_ca_mg_dl = calcium_mg_dl + 0.8 * (4.0 - albumin_g_dl)
```

## Citation

Interpretation of serum calcium in patients with abnormal serum proteins
Payne RB, Little AJ, Williams RB, Milner JR
Br Med J. 1973;4(5893):643-646
DOI: [10.1136/bmj.4.5893.643](https://doi.org/10.1136/bmj.4.5893.643)

## Worked example

### Ca 8.0, albumin 3.0

Given: `albumin_g_dl=3.0, calcium_mg_dl=8.0`

1. corrected = 8.0 + 0.8 * (4.0 - 3.0) = 8.8 mg/dL


## Parameters

- `calcium_mg_dl` (number, optional): Total calcium in mg/dL (4-16). Provide this or calcium_mmol_l.
- `calcium_mmol_l` (number, optional): Total calcium in mmol/L. Converted as mg/dL = mmol/L * 4.0.
- `albumin_g_dl` (number, optional): Albumin in g/dL (1-6). Provide this or albumin_g_l.
- `albumin_g_l` (number, optional): Albumin in g/L. Converted as g/dL = g/L / 10.

## Bulk (POST)

POST the same path with a JSON items array. Price is n times the GET unit. Invalid items return HTTP 400 before settlement.

Method: `POST /api/calc/corrected_calcium`
Max items: 25
Price: unit_amount * n (unit 5000 atomic)
Status: PREVIEW

- 1 to 25 items. Each item uses the same keys as the GET query parameters.
- 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. HTML paywall is GET only.

Example request:

```json
{
  "items": [
    {
      "albumin_g_dl": "3.0",
      "calcium_mg_dl": "8.0"
    },
    {
      "albumin_g_dl": "3.0",
      "calcium_mg_dl": "8.0"
    }
  ]
}
```

Example 200:

```json
{
  "count": 2,
  "path": "/api/calc/corrected_calcium",
  "items": [
    {
      "disclaimer": "Not a medical device. Deterministic published-formula or coded-ontology output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
      "citation": {
        "authors": "Payne RB, Little AJ, Williams RB, Milner JR",
        "doi": "10.1136/bmj.4.5893.643",
        "id": "payne-1973",
        "source": "Br Med J. 1973;4(5893):643-646",
        "title": "Interpretation of serum calcium in patients with abnormal serum proteins"
      },
      "formula": "payne",
      "formula_expression": "corrected_ca_mg_dl = calcium_mg_dl + 0.8 * (4.0 - albumin_g_dl)",
      "albumin_g_dl": 3.0,
      "calcium_mg_dl": 8.0,
      "corrected_calcium_mg_dl": 8.8
    },
    {
      "disclaimer": "Not a medical device. Deterministic published-formula or coded-ontology output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
      "citation": {
        "authors": "Payne RB, Little AJ, Williams RB, Milner JR",
        "doi": "10.1136/bmj.4.5893.643",
        "id": "payne-1973",
        "source": "Br Med J. 1973;4(5893):643-646",
        "title": "Interpretation of serum calcium in patients with abnormal serum proteins"
      },
      "formula": "payne",
      "formula_expression": "corrected_ca_mg_dl = calcium_mg_dl + 0.8 * (4.0 - albumin_g_dl)",
      "albumin_g_dl": 3.0,
      "calcium_mg_dl": 8.0,
      "corrected_calcium_mg_dl": 8.8
    }
  ]
}
```

## Response fields

- `formula` (string): payne
- `formula_expression` (string): Exact expression used
- `calcium_mg_dl` (number): Normalized total calcium
- `albumin_g_dl` (number): Normalized albumin
- `corrected_calcium_mg_dl` (number): Albumin-corrected calcium, 1 decimal
- `citation` (object): Payne 1973 citation
- `disclaimer` (string): Not-a-device notice

## Example JSON

Frozen fixture. Not a live lookup.

```json
{
  "disclaimer": "Not a medical device. Deterministic published-formula or coded-ontology output for autonomous agents. A licensed clinician remains responsible for patient care and billing submissions.",
  "citation": {
    "authors": "Payne RB, Little AJ, Williams RB, Milner JR",
    "doi": "10.1136/bmj.4.5893.643",
    "id": "payne-1973",
    "source": "Br Med J. 1973;4(5893):643-646",
    "title": "Interpretation of serum calcium in patients with abnormal serum proteins"
  },
  "formula": "payne",
  "formula_expression": "corrected_ca_mg_dl = calcium_mg_dl + 0.8 * (4.0 - albumin_g_dl)",
  "albumin_g_dl": 3.0,
  "calcium_mg_dl": 8.0,
  "corrected_calcium_mg_dl": 8.8
}
```

## Errors

- HTTP 400 `invalid_calcium`: calcium_mg_dl (4-16) or calcium_mmol_l (1-4) is required Returned before settlement; you are not charged.
- HTTP 400 `invalid_albumin`: albumin_g_dl (1-6) or albumin_g_l (10-60) is required 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.
- HTTP 402 `payment_required`: Missing or invalid PAYMENT-SIGNATURE; decode the PAYMENT-REQUIRED header
- HTTP 409 `payment_in_progress`: The same authorization nonce is already being settled; retry shortly
- HTTP 429 `rate_limited`: Too many requests from this client
- HTTP 503 `settlement_uncertain`: Settlement is unconfirmed; retry with the same PAYMENT-SIGNATURE
- HTTP 503 `facilitator_unavailable`: Payment facilitator unavailable
- HTTP 503 `facilitator_misconfigured`: Payment facilitator is not configured
- HTTP 503 `facilitator_unauthorized`: Payment facilitator rejected credentials
- HTTP 503 `ledger_unavailable`: Payment ledger unavailable
- HTTP 503 `payment_unavailable`: Payment processing unavailable

## Related tools

- [A1C ↔ eAG](https://magentlab.com/docs/a1c-eag) — Convert A1C percent to estimated average glucose, or the reverse, using Nathan/ADAG.

## Also searched as

- albumin corrected calcium
- Payne formula
- corrected calcium mg/dL
- Payne 1973

## Payment

Required query parameters must be present and valid. 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.

## Guarantees

- Invalid query parameters return HTTP 400 before settlement. You are not charged.
- Settlement finishes before the tool executes. Uncertain settlement fails closed (HTTP 503).
- Execution is timeout-bounded and concurrency-capped.
- Calculator inputs are not persisted. Request logs store path without query.