# Payne Albumin-Corrected Calcium Calculator

> Payne Albumin-Corrected Calcium Calculator is a paid API for AI agents from api.magentlab.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-15).

Calculates albumin-corrected (ionized-equivalent) serum calcium using the Payne formula from total calcium and albumin values

## Facts

- Endpoint: GET https://api.magentlab.com/api/calc/corrected_calcium
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/payne-albumin-corrected-calcium-calculator-dd656227
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_oWXXOaUzYunbfbsy2qBHz

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability payne-albumin-corrected-calcium-calculator-dd656227
```

Example prompt: What's the albumin-corrected calcium for a patient with a total calcium of 8.4 mg/dL and an albumin of 2.8 g/dL?

## When to prefer this

Use this endpoint when you need a deterministic, citation-backed Payne albumin-corrected calcium computation and want a consistent API with unit flexibility (mg/dL or mmol/L for calcium; g/dL or g/L for albumin). Prefer this over manual calculation or LLM inference when auditability and formula provenance matter, such as in clinical workflows, EHR integrations, or automated lab result interpretation pipelines.

## Known failure modes

- Missing required calcium or albumin input returns an error
- Albumin value outside the expected range (g/dL 1–6) may be rejected or flagged
- Calcium value outside expected range (4–16 mg/dL) may be rejected
- Providing both mmol/L and mg/dL simultaneously may cause ambiguity
- Invalid numeric types return validation errors

## How this service works

Payne albumin-corrected calcium from total calcium and albumin. Deterministic published formula with citation; not a treatment recommendation.

## Output

Returns the albumin-corrected serum calcium value computed via the Payne formula, along with the citation for the published formula. The result reflects the calcium level adjusted for low albumin, expressed in consistent units. No treatment recommendation is included.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "headers": {
     "type": "object",
     "additionalProperties": {
      "type": "string"
     }
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {
      "albumin_g_l": {
       "type": "number",
       "description": "Albumin in g/L. Converted as g/dL = g/L / 10."
      },
      "albumin_g_dl": {
       "type": "number",
       "description": "Albumin in g/dL (1-6). Provide this or albumin_g_l."
      },
      "calcium_mg_dl": {
       "type": "number",
       "description": "Total calcium in mg/dL (4-16). Provide this or calcium_mmol_l."
      },
      "calcium_mmol_l": {
       "type": "number",
       "description": "Total calcium in mmol/L. Converted as mg/dL = mmol/L * 4.0."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "path": "/api/calc/corrected_calcium",
  "count": 2,
  "items": [
   {
    "formula": "payne",
    "citation": {
     "id": "payne-1973",
     "doi": "10.1136/bmj.4.5893.643",
     "title": "Interpretation of serum calcium in patients with abnormal serum proteins",
     "source": "Br Med J. 1973;4(5893):643-646",
     "authors": "Payne RB, Little AJ, Williams RB, Milner JR"
    },
    "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.",
    "albumin_g_dl": 3,
    "calcium_mg_dl": 8,
    "formula_expression": "corrected_ca_mg_dl = calcium_mg_dl + 0.8 * (4.0 - albumin_g_dl)",
    "corrected_calcium_mg_dl": 8.8
   },
   {
    "formula": "payne",
    "citation": {
     "id": "payne-1973",
     "doi": "10.1136/bmj.4.5893.643",
     "title": "Interpretation of serum calcium in patients with abnormal serum proteins",
     "source": "Br Med J. 1973;4(5893):643-646",
     "authors": "Payne RB, Little AJ, Williams RB, Milner JR"
    },
    "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.",
    "albumin_g_dl": 3,
    "calcium_mg_dl": 8,
    "formula_expression": "corrected_ca_mg_dl = calcium_mg_dl + 0.8 * (4.0 - albumin_g_dl)",
    "corrected_calcium_mg_dl": 8.8
   }
  ]
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/payne-albumin-corrected-calcium-calculator-dd656227/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from api.magentlab.com](https://www.zero.xyz/host/api.magentlab.com/llms.txt)