# magent PSA Density Calculator (Benson 1992)

> magent PSA Density Calculator (Benson 1992) 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 density (PSAD) using the Benson 1992 formula from serum PSA and prostate volume (or three gland dimensions), and classifies the result into standard clinical bands.

## Facts

- Endpoint: GET https://api.magentlab.com/api/calc/psad
- 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-density-calculator-benson-1992-2e906acf
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_oPB82D-GLMgAFBciuH6NU

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-density-calculator-benson-1992-2e906acf
```

Example prompt: Calculate the PSA density for a patient with a serum PSA of 6.4 ng/mL and prostate dimensions of 4.5 cm length, 3.8 cm width, and 3.2 cm depth using the Benson 1992 formula, and tell me which clinical band it falls into.

## When to prefer this

Choose this endpoint when you need a fast, standards-referenced PSAD computation using the Benson 1992 ellipsoid-like volume formula (L×W×D×0.5) rather than π/6, and you want automatic band classification alongside the raw ratio. Ideal for urology or clinical decision-support agents that already have PSA lab values and either a direct volume measurement or three gland dimensions from ultrasound or MRI.

## Known failure modes

- Missing psa_ng_ml parameter — required for all calls
- Supplying both prostate_volume_ml and dimension parameters simultaneously — mutually exclusive inputs
- Out-of-range PSA value (outside 0.01–10000 ng/mL clamped range)
- Out-of-range prostate volume (outside 1–500 mL)
- Out-of-range dimension (any of length/width/depth outside 1–20 cm)
- Providing only one or two of the three required dimensions without prostate_volume_ml — all three must be supplied together
- Payment failure — endpoint requires $0.005 USDC via x402 protocol

## How this service works

Benson 1992 PSA density: psa_ng_ml / prostate volume (ml). Volume is length_cm × width_cm × depth_cm × 0.5 (D1×D2×D3×1/2), not π/6. Provide PSA with prostate_volume_ml (1-500) or three dimensions (1-20 cm each), not both. Reports dimensionless psad to 3 decimals and retrospective bands <=0.05, 0.05-0.10, >=0.10. magent does not measure the gland or diagnose cancer. Not a medical device.

## Output

Returns a dimensionless PSAD value rounded to 3 decimal places and a retrospective band classification — ≤0.05 (low), 0.05–0.10 (intermediate), or ≥0.10 (elevated) — based on the Benson 1992 definition. Does not diagnose cancer or measure the prostate gland.

## 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": [
      "psa_ng_ml"
     ],
     "properties": {
      "depth_cm": {
       "type": "number",
       "description": "Prostate depth (D3) in cm (1-20). Required with length_cm and width_cm when prostate_volume_ml is omitted."
      },
      "width_cm": {
       "type": "number",
       "description": "Prostate width (D2) in cm (1-20). Required with length_cm and depth_cm when prostate_volume_ml is omitted."
      },
      "length_cm": {
       "type": "number",
       "description": "Prostate length (D1) in cm (1-20). Required with width_cm and depth_cm when prostate_volume_ml is omitted. Benson volume = L×W×D×0.5."
      },
      "psa_ng_ml": {
       "type": "number",
       "description": "Serum prostate-specific antigen in ng/ml (0.01-10000, magent clamp). magent does not assay PSA."
      },
      "prostate_volume_ml": {
       "type": "number",
       "description": "Caller-supplied prostate volume in ml (1-500). Provide this or length_cm, width_cm, and depth_cm, not both. magent does not measure the gland."
      }
     }
    }
   },
   "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-density-calculator-benson-1992-2e906acf/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)