{"uid":"cap_i2DtGPgme-PHAtyqkHON0","slug":"pasi-calculator-fredriksson-1978-05a5be68","name":"PASI Calculator (Fredriksson 1978)","description":"Fredriksson 1978 PASI from four regions. Each region: area 0-6 and erythema, induration, and scaling 0-4. Region score = (sum of three signs) × area × adult weight (head 0.1, upper extremities 0.2, trunk 0.3, lower extremities 0.4). Total max 72. Adult weights only. magent does not examine the skin. No IGA or later severity bands. Not a diagnosis. Not EASI.","url":"https://api.magentlab.com/api/calc/pasi","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":["head_area","head_erythema","head_induration","head_scaling","upper_extremities_area","upper_extremities_erythema","upper_extremities_induration","upper_extremities_scaling","trunk_area","trunk_erythema","trunk_induration","trunk_scaling","lower_extremities_area","lower_extremities_erythema","lower_extremities_induration","lower_extremities_scaling"],"properties":{"head_area":{"enum":[0,1,2,3,4,5,6],"type":"integer","description":"Caller-assigned Fredriksson 1978 PASI area of involvement for this body region (integer 0-6): 0 none, 1 <10%, 2 10-29%, 3 30-49%, 4 50-69%, 5 70-89%, 6 90-100%. magent does not examine the skin."},"trunk_area":{"enum":[0,1,2,3,4,5,6],"type":"integer","description":"Caller-assigned Fredriksson 1978 PASI area of involvement for this body region (integer 0-6): 0 none, 1 <10%, 2 10-29%, 3 30-49%, 4 50-69%, 5 70-89%, 6 90-100%. magent does not examine the skin."},"head_scaling":{"enum":[0,1,2,3,4],"type":"integer","description":"Caller-assigned Fredriksson 1978 PASI scaling for this region (integer 0-4): 0 none, 1 slight, 2 moderate, 3 severe, 4 very severe. magent does not examine the skin."},"head_erythema":{"enum":[0,1,2,3,4],"type":"integer","description":"Caller-assigned Fredriksson 1978 PASI erythema for this region (integer 0-4): 0 none, 1 slight, 2 moderate, 3 severe, 4 very severe. magent does not examine the skin."},"trunk_scaling":{"enum":[0,1,2,3,4],"type":"integer","description":"Caller-assigned Fredriksson 1978 PASI scaling for this region (integer 0-4): 0 none, 1 slight, 2 moderate, 3 severe, 4 very severe. magent does not examine the skin."},"trunk_erythema":{"enum":[0,1,2,3,4],"type":"integer","description":"Caller-assigned Fredriksson 1978 PASI erythema for this region (integer 0-4): 0 none, 1 slight, 2 moderate, 3 severe, 4 very severe. magent does not examine the skin."},"head_induration":{"enum":[0,1,2,3,4],"type":"integer","description":"Caller-assigned Fredriksson 1978 PASI induration for this region (integer 0-4): 0 none, 1 slight, 2 moderate, 3 severe, 4 very severe. magent does not examine the skin."},"trunk_induration":{"enum":[0,1,2,3,4],"type":"integer","description":"Caller-assigned Fredriksson 1978 PASI induration for this region (integer 0-4): 0 none, 1 slight, 2 moderate, 3 severe, 4 very severe. magent does not examine the skin."},"lower_extremities_area":{"enum":[0,1,2,3,4,5,6],"type":"integer","description":"Caller-assigned Fredriksson 1978 PASI area of involvement for this body region (integer 0-6): 0 none, 1 <10%, 2 10-29%, 3 30-49%, 4 50-69%, 5 70-89%, 6 90-100%. magent does not examine the skin."},"upper_extremities_area":{"enum":[0,1,2,3,4,5,6],"type":"integer","description":"Caller-assigned Fredriksson 1978 PASI area of involvement for this body region (integer 0-6): 0 none, 1 <10%, 2 10-29%, 3 30-49%, 4 50-69%, 5 70-89%, 6 90-100%. magent does not examine the skin."},"lower_extremities_scaling":{"enum":[0,1,2,3,4],"type":"integer","description":"Caller-assigned Fredriksson 1978 PASI scaling for this region (integer 0-4): 0 none, 1 slight, 2 moderate, 3 severe, 4 very severe. magent does not examine the skin."},"upper_extremities_scaling":{"enum":[0,1,2,3,4],"type":"integer","description":"Caller-assigned Fredriksson 1978 PASI scaling for this region (integer 0-4): 0 none, 1 slight, 2 moderate, 3 severe, 4 very severe. magent does not examine the skin."},"lower_extremities_erythema":{"enum":[0,1,2,3,4],"type":"integer","description":"Caller-assigned Fredriksson 1978 PASI erythema for this region (integer 0-4): 0 none, 1 slight, 2 moderate, 3 severe, 4 very severe. magent does not examine the skin."},"upper_extremities_erythema":{"enum":[0,1,2,3,4],"type":"integer","description":"Caller-assigned Fredriksson 1978 PASI erythema for this region (integer 0-4): 0 none, 1 slight, 2 moderate, 3 severe, 4 very severe. magent does not examine the skin."},"lower_extremities_induration":{"enum":[0,1,2,3,4],"type":"integer","description":"Caller-assigned Fredriksson 1978 PASI induration for this region (integer 0-4): 0 none, 1 slight, 2 moderate, 3 severe, 4 very severe. magent does not examine the skin."},"upper_extremities_induration":{"enum":[0,1,2,3,4],"type":"integer","description":"Caller-assigned Fredriksson 1978 PASI induration for this region (integer 0-4): 0 none, 1 slight, 2 moderate, 3 severe, 4 very severe. magent does not examine the skin."}}}},"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_nphqvhxOQaL47c_9IBTyF","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":"Computes the Psoriasis Area and Severity Index (PASI) score from caller-supplied area, erythema, induration, and scaling values across four body regions.","exampleAgentPrompt":"Calculate the PASI score for my patient: head area 2, erythema 2, induration 1, scaling 2; upper extremities area 3, erythema 3, induration 2, scaling 2; trunk area 4, erythema 2, induration 2, scaling 3; lower extremities area 3, erythema 2, induration 1, scaling 2.","exampleUseCases":[{"title":"Baseline PASI before biologic therapy","prompt":"I need the PASI score for a patient about to start a biologic: head area 3, erythema 3, induration 2, scaling 3; upper extremities area 2, erythema 2, induration 2, scaling 2; trunk area 4, erythema 3, induration 3, scaling 3; lower extremities area 3, erythema 2, induration 2, scaling 3."},{"title":"Tracking treatment response over time","prompt":"Run a PASI calculation so I can compare with last visit — head area 1, erythema 1, induration 1, scaling 1; upper extremities area 1, erythema 2, induration 1, scaling 1; trunk area 2, erythema 1, induration 1, scaling 2; lower extremities area 1, erythema 1, induration 1, scaling 1."},{"title":"Clinical trial eligibility screening","prompt":"What is the PASI score for this trial candidate: head area 2, erythema 2, induration 2, scaling 2; upper extremities area 4, erythema 3, induration 3, scaling 3; trunk area 5, erythema 4, induration 3, scaling 4; lower extremities area 4, erythema 3, induration 3, scaling 3? We need to confirm they meet the moderate-to-severe threshold."}],"resultDescription":"Returns the total PASI score on a 0–72 scale, calculated using the Fredriksson 1978 formula: each region's sign sum (erythema + induration + scaling, each 0–4) is multiplied by the area score (0–6) and the region's adult body-surface weight (head 0.1, upper extremities 0.2, trunk 0.3, lower extremities 0.4). Regional sub-scores and the aggregate total are returned. The endpoint performs arithmetic only and does not include IGA bands, EASI scoring, or diagnostic interpretation.","failureModes":["Missing any of the 16 required query parameters returns an error","Out-of-range area values (outside 0–6) or sign values (outside 0–4) are rejected","Invalid data types (non-integer or floating-point) for area or sign fields cause validation failure","No partial scoring — all four regions must be supplied"],"whenToPreferThis":"Use this endpoint when you need a standards-compliant Fredriksson 1978 PASI score computed from discrete clinical observations you have already gathered. It is the right choice for automating PASI arithmetic in EHR workflows, clinical trial data pipelines, or telemedicine tools where a clinician has already assessed the patient. Do not use it if you need EASI scoring, IGA grading, pediatric adjustments, or any diagnostic interpretation — it returns a raw numeric score only.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-15T07:06:01.748Z","isFirstParty":false}