# magent PSA Doubling Time Calculator (Pound 1999)

> magent PSA Doubling Time Calculator (Pound 1999) 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).

Calculates PSA doubling time (PSADT) in months using the Pound 1999 two-point first-order kinetic formula from two rising PSA values and the interval between them.

## Facts

- Endpoint: GET https://api.magentlab.com/api/calc/psadt
- 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-psa-doubling-time-calculator-pound-1999-a1575f8b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_kuCyF39y1fHIF9pnxnwPo

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-psa-doubling-time-calculator-pound-1999-a1575f8b
```

Example prompt: My patient had a PSA of 0.5 ng/mL six months ago and now it's 1.2 ng/mL — can you calculate the PSA doubling time using the Pound 1999 formula and tell me whether it falls in the <=10 or >10 month category?

## When to prefer this

Use this endpoint when you need a fast, reproducible Pound 1999 two-point PSADT calculation from exactly two serial PSA measurements and a known interval. Ideal for clinical decision support workflows, EMR integrations, or agentic oncology tools that need PSADT with the standard <=10/> 10 month Pound classification. Not suitable if you need multi-point regression-based PSADT, PSA velocity in ng/mL/year, or if you need to actually measure or retrieve PSA values from a lab system.

## Known failure modes

- psa2 not greater than psa1 — PSA must be rising for this formula to apply; returns error
- psa1 or psa2 outside 0.2–10000 ng/mL range — returns validation error
- interval_months outside 0.25–120 range — returns validation error or clamped result
- missing required query parameters — returns 400 or schema error
- division by zero if psa values are equal — psa2 must strictly exceed psa1

## How this service works

Pound 1999 PSA doubling time from two rising PSA values: psadt_months = ln(2) x interval_months / ln(psa2_ng_ml / psa1_ng_ml), 1 decimal. PSA each 0.2-10000 ng/mL; psa2 must exceed psa1; interval_months 0.25-120. Reports the Pound split <=10 vs >10 months (exactly 10.0 is <=10). Two-point first-order kinetics only. magent does not measure PSA. Not a medical device.

## Output

Returns the PSA doubling time in months rounded to 1 decimal place, calculated via ln(2) × interval_months / ln(psa2/psa1), along with a Pound 1999 risk classification indicating whether PSADT is <=10 months (shorter, more aggressive) or >10 months (longer, less aggressive). Exactly 10.0 months is classified as <=10.

## 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": [
      "psa1_ng_ml",
      "psa2_ng_ml",
      "interval_months"
     ],
     "properties": {
      "psa1_ng_ml": {
       "type": "number",
       "description": "Earlier serum PSA in ng/mL (0.2-10000). Pound biochemical recurrence used detectable PSA ≥0.2 ng/mL. magent does not measure PSA."
      },
      "psa2_ng_ml": {
       "type": "number",
       "description": "Later serum PSA in ng/mL (0.2-10000). Must be greater than psa1_ng_ml (rising). magent does not measure PSA."
      },
      "interval_months": {
       "type": "number",
       "description": "Months between the two PSA values (0.25-120, magent clamp). Pound 1999 does not publish an input band for this two-point tool."
      }
     }
    }
   },
   "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-psa-doubling-time-calculator-pound-1999-a1575f8b/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)