{"uid":"cap_7h6WfKvGD6krN96WEODoQ","slug":"asas-2011-peripheral-spa-classification-calculator-2a7dca1f","name":"ASAS 2011 Peripheral SpA Classification Calculator","description":"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.","url":"https://api.magentlab.com/api/calc/asas_peripheral_spa","method":"GET","headers":{},"bodySchema":{"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 5 additional feature is past or present dactylitis diagnosed by a physician; the same caller flag counts toward arm B. true or false. magent does not examine digits."},"enthesitis":{"type":"boolean","description":"Current enthesitis as assigned by the caller (Rudwaleit 2011 set 2D entry). Table 5 additional feature is past or present spontaneous pain or tenderness at an enthesis; the same caller flag counts toward arm B. true or false. magent does not examine entheses."},"family_history_spa":{"type":"boolean","description":"Family history of SpA as assigned by the caller (Rudwaleit 2011 arm B): first-degree or second-degree relatives with ankylosing spondylitis, psoriasis, acute uveitis, reactive arthritis, or IBD. true or false. magent does not take a pedigree."},"preceding_infection":{"type":"boolean","description":"Urethritis/cervicitis or diarrhoea within 1 month before arthritis, enthesitis, or dactylitis, as assigned by the caller (Rudwaleit 2011 arm A). true or false. magent does not take a history."},"sacroiliitis_on_imaging":{"type":"boolean","description":"Sacroiliitis on imaging as assigned by the caller (Rudwaleit 2011 arm A): definite radiographic sacroiliitis (bilateral grade 2–4 or unilateral grade 3–4) or active inflammation on MRI highly suggestive of SpA-associated sacroiliitis. true or false. magent does not read films."}}}},"additionalProperties":false},"output":{"type":"object","required":["type"],"properties":{"type":{"type":"string"},"example":{"type":"object"}}}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.005","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.005/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.005","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.005","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_nRarxiB55cCyoisYpO42X","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.005","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"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.","exampleAgentPrompt":"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?","exampleUseCases":[{"title":"Rheumatology clinic SpA workup","prompt":"I have a patient with current asymmetric arthritis of the lower limbs and dactylitis. He's HLA-B27 positive and had a preceding GI infection. No psoriasis, no IBD, no uveitis, no sacroiliitis on imaging, no past IBP, no family history. Does he classify as peripheral SpA under ASAS 2011?"},{"title":"Uveitis and sacroiliitis patient screening","prompt":"My patient presents with current enthesitis and has a confirmed history of uveitis and sacroiliitis on imaging. No arthritis, no dactylitis, no psoriasis, no IBD, no preceding infection, not HLA-B27 positive, no past IBP, no family history of SpA. Does she meet the ASAS peripheral SpA criteria?"},{"title":"Family history and multi-feature Arm B evaluation","prompt":"Patient has current arthritis and dactylitis, past inflammatory back pain, and a family history of SpA. No psoriasis, no IBD, no preceding infection, HLA-B27 negative, no uveitis, no sacroiliitis on imaging, no enthesitis. Please classify using ASAS 2011 peripheral SpA criteria and tell me which arm applies."}],"resultDescription":"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.","failureModes":["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"],"whenToPreferThis":"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.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-13T12:59:32.492Z","isFirstParty":false}