# Kaplan 1990 Estimated Plasma Volume for Therapeutic Plasma Exchange

> Kaplan 1990 Estimated Plasma Volume for Therapeutic Plasma Exchange 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 estimated plasma volume (EPV) in liters and milliliters using the Kaplan 1990 formula for therapeutic plasma exchange planning.

## Facts

- Endpoint: GET https://api.magentlab.com/api/calc/tpe
- 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/kaplan-1990-estimated-plasma-volume-for-therapeutic-plasma-exchange-f884d898
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_I88X3fHyA1sPbhKQ-oRyY

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 kaplan-1990-estimated-plasma-volume-for-therapeutic-plasma-exchange-f884d898
```

Example prompt: Calculate the estimated plasma volume for a 70 kg patient with a hematocrit of 38% using the Kaplan 1990 formula for therapeutic plasma exchange planning.

## When to prefer this

Use this endpoint when you need the Kaplan 1990 formula specifically for one estimated plasma volume in therapeutic plasma exchange planning, given patient weight and hematocrit. Prefer this over general blood volume calculators (e.g., Nadler) when the clinical need is TPE procedure dosing rather than total blood volume estimation, iron deficit (Ganzoni), or platelet-replacement tables.

## Known failure modes

- Missing hematocrit_percent returns a validation error (it is required)
- Hematocrit value outside the accepted range of 10–70 percent returns an error
- Neither weight_kg nor weight_lb provided causes a missing parameter error
- Non-numeric inputs for weight or hematocrit cause a type validation error

## How this service works

Kaplan 1990 estimated plasma volume for therapeutic plasma exchange: epv_l = 0.065 * weight_kg * (1 - hematocrit_percent/100). Returns one plasma volume in liters and milliliters. Hematocrit is a percent (10-70), not a 0-1 fraction. Deterministic published arithmetic with citation. Not an apheresis order, Nadler blood volume, Ganzoni iron deficit, or a 1.5-PV / removal-percent table.

## Output

Returns the estimated plasma volume (EPV) calculated as 0.065 × weight_kg × (1 − hematocrit_percent/100), expressed in both liters and milliliters, with citation to Kaplan 1990.

## 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": [
      "hematocrit_percent"
     ],
     "properties": {
      "weight_kg": {
       "type": "number",
       "description": "Weight in kilograms. Provide weight_kg or weight_lb."
      },
      "weight_lb": {
       "type": "number",
       "description": "Weight in pounds. Converted as kg = lb * 0.45359237."
      },
      "hematocrit_percent": {
       "type": "number",
       "description": "Hematocrit as a percent (10-70). Required. Not a 0-1 fraction; magent does not accept hematocrit_fraction."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/kaplan-1990-estimated-plasma-volume-for-therapeutic-plasma-exchange-f884d898/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
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