A–a Oxygen Gradient

Alveolar–arterial oxygen gradient (sea level).

How to use

Call with the inputs below. Boolean inputs are optional (absent = false). Returns the value, an interpretation, and a breakdown. Deterministic — no network call.

Parameters

Name	Type		Description
pao2	number	required	Arterial PaO₂ — unit: mmHg
paco2	number	required	Arterial PaCO₂ — unit: mmHg
fio2_percent	number	optional	FiO₂ percent (default 21 = room air) — unit: %
age	number	optional	Age (for expected gradient) — unit: years

Example input

{
  "pao2": 70,
  "paco2": 40,
  "fio2_percent": 21,
  "age": 60
}

Example output

{
  "calculator": "A–a Oxygen Gradient",
  "category": "Pulmonary",
  "value": "29.7 mmHg",
  "interpretation": "Elevated vs expected ~15.1 mmHg for age.",
  "severity": "high",
  "detail": {
    "Alveolar PAO₂": "99.7 mmHg",
    "Expected (age)": "15.1 mmHg"
  }
}

Call it (MCP tools/call)

{
  "method": "tools/call",
  "params": {
    "name": "calc_aa_gradient",
    "arguments": {
      "pao2": 70,
      "paco2": 40,
      "fio2_percent": 21,
      "age": 60
    }
  }
}

Endpoint: POST https://clinical-mcp.mcharge.in/mcp (Streamable HTTP).