# ASAS 2011 Peripheral SpA Classification Calculator

> ASAS 2011 Peripheral SpA Classification Calculator is a paid API for AI agents from api.magentlab.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-13).

Applies the ASAS 2011 peripheral spondyloarthritis classification criteria (Rudwaleit set 2D / fig 1 + table 5) to determine if a patient meets classification thresholds via Arm A or Arm B.

## Facts

- Endpoint: GET https://api.magentlab.com/api/calc/asas_peripheral_spa
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/asas-2011-peripheral-spa-classification-calculator-2a7dca1f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_7h6WfKvGD6krN96WEODoQ

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 asas-2011-peripheral-spa-classification-calculator-2a7dca1f
```

Example prompt: Run the ASAS 2011 peripheral SpA classification for a patient who has current arthritis and enthesitis, tests positive for HLA-B27, has a history of uveitis, no psoriasis, no IBD, no preceding infection, no sacroiliitis on imaging, no past inflammatory back pain, and no family history of SpA — does she meet classification criteria via Arm A or Arm B?

## When to prefer this

Use this endpoint when you need to apply the specific ASAS 2011 peripheral SpA classification algorithm (Rudwaleit set 2D) and the patient has a peripheral presentation (arthritis, enthesitis, or dactylitis) rather than predominant axial symptoms. Do not use for axial SpA classification (ASAS 2009 axial criteria apply there), and do not confuse with ESSG or Amor criteria — those are distinct algorithms not implemented here.

## Known failure modes

- Missing required boolean query parameters returns a validation error
- Entry criterion not met (no current arthritis, enthesitis, or dactylitis) results in classification not met regardless of arm features
- Ambiguous or missing HLA-B27 or imaging results passed as false may undercount arm A features
- Caller-assigned inputs that do not reflect actual clinical findings will produce unreliable classification output

## How this service works

ASAS 2011 peripheral SpA classification (Rudwaleit set 2D / fig 1 + table 5). Required: current arthritis, enthesitis, or dactylitis. Arm A: ≥1 of psoriasis, IBD, preceding infection, HLA-B27, uveitis, sacroiliitis on imaging. Arm B: ≥2 of arthritis, enthesitis, dactylitis, IBP in the past, family history of SpA. Not a diagnosis. Not ASAS 2009 axial. Not ESSG/Amor. magent does not examine joints or assay HLA-B27.

## Output

Returns whether the patient meets ASAS 2011 peripheral SpA classification criteria, indicating which arm (A or B) was satisfied, whether the mandatory entry criterion (current arthritis, enthesitis, or dactylitis) was met, and the specific features contributing to the classification. Not 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": [
      "arthritis",
      "enthesitis",
      "dactylitis",
      "psoriasis",
      "ibd",
      "preceding_infection",
      "hla_b27",
      "uveitis",
      "sacroiliitis_on_imaging",
      "ibp_past",
      "family_history_spa"
     ],
     "properties": {
      "ibd": {
       "type": "boolean",
       "description": "Past or present Crohn's disease or ulcerative colitis diagnosed by a physician, as assigned by the caller (Rudwaleit 2011 arm A). true or false. magent does not diagnose IBD."
      },
      "hla_b27": {
       "type": "boolean",
       "description": "HLA-B27 positive as assigned by the caller (Rudwaleit 2011 arm A). true or false. magent does not assay HLA-B27."
      },
      "uveitis": {
       "type": "boolean",
       "description": "Past or present uveitis confirmed by an ophthalmologist, as assigned by the caller (Rudwaleit 2011 arm A). true or false. magent does not examine the eye."
      },
      "ibp_past": {
       "type": "boolean",
       "description": "Inflammatory back pain in the past according to experts, as assigned by the caller (Rudwaleit 2011 arm B). true or false. magent does not take a history."
      },
      "arthritis": {
       "type": "boolean",
       "description": "Current peripheral arthritis (usually asymmetric and/or of lower limbs) as assigned by the caller (Rudwaleit 2011 set 2D entry). Table 5 additional feature is past or present synovitis diagnosed by a physician; the same caller flag counts toward arm B. true or false. magent does not examine joints."
      },
      "psoriasis": {
       "type": "boolean",
       "description": "Past or present psoriasis diagnosed by a physician, as assigned by the caller (Rudwaleit 2011 arm A). true or false. magent does not examine skin."
      },
      "dactylitis": {
       "type": "boolean",
       "description": "Current dactylitis as assigned by the caller (Rudwaleit 2011 set 2D entry). Table
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/asas-2011-peripheral-spa-classification-calculator-2a7dca1f/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)