# CASPAR Criteria Calculator for Psoriatic Arthritis

> CASPAR Criteria Calculator for Psoriatic Arthritis 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).

Computes the Taylor 2006 CASPAR score for psoriatic arthritis classification and returns whether the criteria are met (score ≥ 3).

## Facts

- Endpoint: GET https://api.magentlab.com/api/calc/caspar
- 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/caspar-criteria-calculator-for-psoriatic-arthritis-172283ad
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_AvzqSJcOOxn1k3AZnjmri

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 caspar-criteria-calculator-for-psoriatic-arthritis-172283ad
```

Example prompt: Score this patient for psoriatic arthritis using CASPAR criteria: they have confirmed inflammatory articular disease, current psoriasis is present, nail dystrophy is present, rheumatoid factor is negative, dactylitis history is positive, and no juxtaarticular new bone on imaging — no personal or family history flags needed since current psoriasis is true.

## When to prefer this

Use this endpoint when you need a programmatic, auditable computation of the Taylor 2006 CASPAR score for psoriatic arthritis classification in a rheumatology or clinical research workflow. Prefer it over manual scoring tables when integrating into EHR pipelines, research eligibility screens, or agentic clinical decision support. Note: this endpoint computes criteria only — it does not examine patients, read imaging, or provide diagnoses. It should not be confused with the older Moll and Wright criteria.

## Known failure modes

- Missing required inflammatory_articular_disease parameter returns validation error
- Invalid boolean values for any parameter return schema error
- inflammatory_articular_disease false short-circuits classification regardless of score
- Score may be misleading if caller-assigned clinical flags are inaccurate — garbage-in, garbage-out
- Network or payment authorization failure returns 402 or connectivity error

## How this service works

Taylor 2006 CASPAR classification criteria for psoriatic arthritis. Required: inflammatory_articular_disease true (joint, spine, or enthesis). Score: current psoriasis 2; personal history 1 only if current is false; family history 1 only if current and personal are false; nail dystrophy 1; RF-negative 1; dactylitis (current or history) 1; juxtaarticular new bone 1. Classified iff score ≥3 (max 8). Not a diagnosis. Not Moll and Wright. magent does not examine skin or read films.

## Output

Returns the total CASPAR score (integer, 0–8), whether the patient meets classification (score ≥ 3 with inflammatory articular disease confirmed), and optionally per-criterion point contributions. Does not provide a clinical diagnosis.

## 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": [
      "inflammatory_articular_disease",
      "current_psoriasis",
      "personal_history_psoriasis",
      "family_history_psoriasis",
      "nail_dystrophy",
      "rheumatoid_factor_negative",
      "dactylitis",
      "juxtaarticular_new_bone"
     ],
     "properties": {
      "dactylitis": {
       "type": "boolean",
       "description": "Current swelling of an entire digit, or a history of dactylitis recorded by a rheumatologist, as assigned by the caller (Taylor 2006). true scores 1. magent does not examine digits."
      },
      "nail_dystrophy": {
       "type": "boolean",
       "description": "Typical psoriatic nail dystrophy including onycholysis, pitting, and hyperkeratosis on current examination, as assigned by the caller (Taylor 2006). true scores 1. magent does not examine nails."
      },
      "current_psoriasis": {
       "type": "boolean",
       "description": "Current psoriasis as assigned by the caller (Taylor 2006): psoriatic skin or scalp disease present today as judged by a rheumatologist or dermatologist. true scores 2. When true, personal_history_psoriasis and family_history_psoriasis do not add. magent does not examine skin."
      },
      "juxtaarticular_new_bone": {
       "type": "boolean",
       "description": "Radiographic ill-defined ossification near joint margins, excluding osteophyte formation, on plain radiographs of the hand or foot, as assigned by the caller (Taylor 2006). true scores 1. magent does not read films."
      },
      "family_history_psoriasis": {
       "type": "boolean",
       "description": "Family history of psoriasis as assigned by the caller (Taylor 2006): first- or second-degree relative according to patient report. true scores 1 only if current_psoriasis is false and personal_history_psoriasis is false. magent does not take a pedigree."
      },
      "personal_history_psoriasis": {
       "type": "boolean",
       "descripti
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/caspar-criteria-calculator-for-psoriatic-arthritis-172283ad/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)