# magent Chen 2013 Kinetic eGFR (KeGFR) Calculator

> magent Chen 2013 Kinetic eGFR (KeGFR) Calculator is a paid API for AI agents from api.magentlab.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14).

Computes the Chen 2013 kinetic estimated GFR (KeGFR) from two serial plasma creatinine values, time between them, and a caller-assigned steady-state creatinine with corresponding eGFR/CrCl.

## Facts

- Endpoint: GET https://api.magentlab.com/api/calc/kegfr
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/magent-chen-2013-kinetic-egfr-kegfr-calculator-406faf1b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_N75lzkwCKib16J9EsuJFV

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 magent-chen-2013-kinetic-egfr-kegfr-calculator-406faf1b
```

Example prompt: A patient has a first creatinine of 1.2 mg/dL and a second of 2.1 mg/dL measured 18 hours later; their steady-state creatinine is 1.0 mg/dL with a corresponding eGFR of 75 mL/min and the max delta creatinine is 1.5 mg/dL/day — can you compute their kinetic eGFR using the Chen 2013 formula?

## When to prefer this

Use this endpoint when a patient's creatinine is acutely changing and a steady-state GFR assumption would overestimate or underestimate true kidney function. Prefer this over standard CKD-EPI or MDRD lookups when you have two serial creatinine measurements within 72 hours and want a kinetically-adjusted GFR. Do not use this for CKD staging, dialysis dosing prescription, or when you need CKD-EPI or MDRD specifically — those are not computed here.

## Known failure modes

- Missing required query parameters (creatinine_1_mg_dl, creatinine_2_mg_dl, delta_hours, steady_state_creatinine_mg_dl, steady_state_egfr, max_delta_pcr_mg_dl_day) returns an error
- Creatinine values outside 0.1–20 mg/dL range may return validation error
- delta_hours outside 1–72 hours may be rejected
- steady_state_egfr outside 5–200 mL/min may fail validation
- max_delta_pcr_mg_dl_day outside 0.5–3 may be rejected
- Payment not provided or insufficient (x402 payment required at $0.005 USDC per call)

## How this service works

Chen 2013 kinetic eGFR (KeGFR) from two plasma creatinines, hours between them, caller-assigned steady-state creatinine and corresponding eGFR/CrCl, and required max_delta_pcr_mg_dl_day (Chen usual default 1.5). KeGFR = (SSPCr * CrCl / MeanPCr) * (1 - 24*dPCr / (dTime_hours * MaxdPCr/Day)), clamped at 0 when that (1 - ratio) term is negative. Creatinine mg/dL only. Not a CKD-EPI result. Not a dialysis prescription. magent does not compute MDRD or CKD-EPI.

## Output

Returns a numeric kinetic eGFR value in mL/min calculated via the Chen 2013 formula: KeGFR = (SSPCr × CrCl / MeanPCr) × (1 − 24×dPCr / (dTime_hours × MaxdPCr/Day)), clamped to 0 if the bracketed term is negative. The result reflects estimated real-time kidney function when creatinine is not at steady state.

## 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": [
      "creatinine_1_mg_dl",
      "creatinine_2_mg_dl",
      "delta_hours",
      "steady_state_creatinine_mg_dl",
      "steady_state_egfr",
      "max_delta_pcr_mg_dl_day"
     ],
     "properties": {
      "delta_hours": {
       "type": "number",
       "description": "Hours between creatinine_1 and creatinine_2 (1-72). Chen: endpoints <48-72 h apart."
      },
      "steady_state_egfr": {
       "type": "number",
       "description": "Caller-assigned eGFR/CrCl in mL/min corresponding to steady_state_creatinine_mg_dl (5-200). magent does not compute MDRD or CKD-EPI."
      },
      "creatinine_1_mg_dl": {
       "type": "number",
       "description": "First plasma creatinine in mg/dL (0.1-20). mg/dL only."
      },
      "creatinine_2_mg_dl": {
       "type": "number",
       "description": "Second plasma creatinine in mg/dL (0.1-20). mg/dL only."
      },
      "max_delta_pcr_mg_dl_day": {
       "type": "number",
       "description": "Maximum creatinine rise per day in mg/dL (0.5-3). Chen usual default 1.5. Required; magent does not omit it."
      },
      "steady_state_creatinine_mg_dl": {
       "type": "number",
       "description": "Steady-state plasma creatinine in mg/dL (0.1-20) corresponding to steady_state_egfr. mg/dL only."
      }
     }
    }
   },
   "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/magent-chen-2013-kinetic-egfr-kegfr-calculator-406faf1b/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)