Select the patient's symptoms and findings. The tool estimates pre-test probability across eight autoimmune conditions and generates specific testing recommendations — so you order the right labs the first time.
Answer the questions below based on your symptoms. The tool will help you understand whether autoimmune blood testing may make sense for you, and which conditions to bring up with your doctor.
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10–20%
of healthy people have a positive ANA at 1:80 dilution. Ordering ANA without clinical pre-screening virtually guarantees false positives in primary care.
<5%
of positive ANAs in primary care settings lead to a confirmed autoimmune diagnosis. Indiscriminate testing creates patient anxiety and unnecessary specialist referrals.
3–5×
higher rheumatology referral rate from PCPs who order ANA without clinical pre-screening — the majority without a diagnosable autoimmune condition.
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Answer each question based on your symptoms. You'll see a summary of which autoimmune conditions your symptoms may relate to, and what tests your doctor might consider. This is not a diagnosis — it's a starting point for a conversation with your doctor.
Clinical decision support only. This tool estimates pre-test probability to guide test ordering decisions. It is not a diagnostic instrument and does not replace clinical judgment. Autoimmune serology has low positive predictive value in low-pretest-probability settings — features selected should reflect objective findings, not subjective symptoms alone.
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Constitutional SymptomsGeneral Symptoms
Systemic inflammation — non-specific but raises suspicion when combined with organ-specific findings
General feelings that something is wrong with your health
Unexplained fatigue
Not explained by sleep disorder, anemia, depression, or thyroid disease
Feeling very tired even after resting, for weeks or months
Unexplained fevers
Low-grade or episodic; no clear infectious etiology
Running a temperature without an obvious reason like a cold or flu
Unintentional weight loss
Consider malignancy; raises suspicion alongside multi-system features
Losing weight without trying, over weeks or months
Lymphadenopathy
Generalized or regional; SLE, Sjögren's; rule out lymphoma
Swollen glands in the neck, armpits, or groin
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Joint Symptoms
The most important discriminator — inflammatory pattern vs mechanical/OA must be established before ordering
Pain, swelling, or stiffness in your joints
Inflammatory joint pain pattern
Worse at rest / in morning, improves with activity — distinguishes from OA
Joint pain that is worse in the morning and gets better as you move around
Morning stiffness >45 minutes
Prolonged stiffness is a hallmark of synovitis; >1 hr is strongly inflammatory
Joints feel stiff for 45+ minutes after waking up before loosening
Small joint involvement
MCPs, PIPs, wrists, MTPs — bilateral symmetric pattern favors RA or SLE
Aching or swelling in knuckles, fingers, or wrists
Objective joint swelling
Visible or palpable synovitis — not just tenderness; markedly raises probability
Joints that look visibly puffy, not just painful
Inflammatory back pain
Improves with exercise not rest; wakes at night; onset <45 yrs — ASAS IBP criteria
Back pain that improves when you move but wakes you from sleep at night
Dactylitis ("sausage digit")
Diffuse swelling of entire finger or toe — highly specific for psoriatic arthritis
An entire finger or toe that swells up uniformly, like a sausage
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Skin Findings
Cutaneous manifestations are often the most diagnostically specific — malar rash and purpura carry high LR+
Rashes or changes to your skin and nails
Malar (butterfly) rash
Fixed erythema across cheeks and nasal bridge, spares nasolabial folds; worsened by sun
A butterfly-shaped rash across both cheeks and the bridge of the nose
Photosensitivity
Rash or symptom flare after sun/UV exposure — documented or by history
A rash or worsening of symptoms after being out in the sun
Psoriasis (skin or nails)
Any subtype; nail pitting, onycholysis, or oil-drop sign also qualifies
Scaly skin plaques, or pitted / thickened / discolored nails
Palpable purpura
Raised, non-blanching lesions (legs) — highly specific for small-vessel vasculitis
Raised purple spots on the skin (especially legs) that don't fade when pressed
A lace-like, purplish mottled pattern on the skin of the limbs
Non-scarring alopecia
Diffuse thinning or hairline fragility ("lupus hair") — rule out thyroid, iron deficiency
Increased hair loss or thinning without an obvious cause
Skin thickening or tightening
Sclerodactyly or proximal induration — hallmark of systemic sclerosis
Skin on the hands or face that feels unusually tight or thickened
Gottron's papules / heliotrope
Purple-red papules over knuckles or periorbital heliotrope discoloration — dermatomyositis
Reddish-purple patches over the knuckles, or a purplish discoloration around the eyelids
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Mucosal & Sicca Symptoms
Exocrine gland dysfunction — primary Sjögren's; also secondary in SLE, SSc, RA
Dryness or sores in your mouth and eyes
Dry eyes (>3 months)
Gritty, sandy, or burning — persistent; not medication-related or age-appropriate alone
Eyes that feel dry, gritty, or burning most days for more than 3 months
Dry mouth (>3 months)
Needs water to swallow food; accelerated dental caries; wakes at night to drink
Persistent dry mouth — needing water to swallow food, or lots of dental problems
Oral ulcers (recurrent)
In SLE typically painless on palate/buccal — distinct from painful aphthous ulcers
Mouth sores that keep coming back, often painless
Parotid gland swelling
Bilateral, painless, recurrent — one of the most specific features for primary Sjögren's
Swelling in front of the ears or below the jaw, especially on both sides
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Raynaud's Phenomenon
Secondary Raynaud's: onset >30 yrs, asymmetric, digital ulcers, ANA+ — always evaluate for CTD
Color changes in your fingers or toes triggered by cold or stress
Triphasic color changes in digits
White (pallor) → blue (cyanosis) → red (hyperemia) with cold or emotional stress
Fingers turning white, then blue, then red in the cold or with stress
Digital ulcers or pitting scars
Fingertip ulceration or pitted scars — highly specific for systemic sclerosis
Painful sores or small scars on the tips of the fingers
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ENT / Upper Airway
GPA presents with upper airway disease in >90% of cases — often misattributed to recurrent sinusitis for years
Symptoms in your nose, sinuses, or ears
Chronic or refractory sinusitis
Not responsive to antibiotics; bloody or crusted nasal discharge; recurrent episodes
Sinus problems that won't clear up, even with antibiotics
Nasal crusting or recurrent epistaxis
Bloody crusts; septal perforation indicates advanced cartilage destruction in GPA
Frequent unexplained nosebleeds or bloody crusts inside the nose
GPA clinical pearl: Refractory sinusitis in a younger patient — especially with any of bloody discharge, nasal crusting, or recurrent epistaxis — should prompt ANCA testing, not another course of antibiotics.Refractory sinus problems can sometimes be caused by inflammation from an autoimmune condition rather than infection.
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Organ Involvement
Multi-system disease markedly raises pre-test probability — renal and pulmonary features may require urgent referral
Symptoms affecting your kidneys, lungs, heart, or nerves
Hematuria (micro or macro)
Perform UA + microscopy — RBC casts = GN; urgent evaluation for SLE and AAV
Blood in the urine (visible or found on a urine test)
Proteinuria or rising creatinine
Nephrotic-range proteinuria in SLE; rapidly rising Cr in AAV — both urgent
Protein found in urine, or a rising creatinine level on blood tests
Pleuritis or pericarditis
Unexplained serositis — SLE, RA, and inflammatory myopathy can all present this way
Sharp chest pain when breathing, or fluid around the heart or lungs
Peripheral neuropathy
Mononeuritis multiplex → vasculitis; small fiber neuropathy → Sjögren's
Numbness, tingling, burning, or weakness in hands or feet
Hemoptysis or pulmonary infiltrates
Alveolar hemorrhage = emergency; pulmonary nodules in GPA; ILD in myositis/SSc
Coughing up blood, or abnormal findings on a chest X-ray or CT
Proximal muscle weakness
Difficulty rising from chair or climbing stairs without arm support — order CK
Weakness getting up from a chair, climbing stairs, or lifting arms overhead
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Incidental Lab FindingsPrevious Test Results
Objective lab abnormalities that independently raise pre-test probability
Any blood or urine results your doctor has already shared with you
Elevated ESR or CRP
Unexplained systemic inflammation — independently increases pre-test probability
Blood tests showing inflammation in the body (ESR or CRP levels are elevated)
Select clinical features above to receive pre-test probability estimates and specific testing recommendations.
Check any symptoms that apply to you to see which conditions may be worth discussing with your doctor.
Conditions with elevated signal
Conditions to discuss with your doctor
Suggested testing
Tests your doctor may consider
Go deeper — specific calculators
Learn more about these conditions
Important: This tool is not a diagnosis. Share this summary with your doctor and discuss your full medical history and examination together.
Evidence & References
Slight-Webb S, et al. Autoantibody-positive healthy individuals display unique immune profiles that may predict future autoimmune disease. JCI Insight. 2016;1(7):e88311.
Yazdany J, Schmajuk G, et al. American College of Rheumatology. Choosing Wisely: Five things physicians and patients should question in rheumatology. Arthritis Care Res. 2013;65(3):329–339.
Aringer M, et al. 2019 EULAR/ACR Classification Criteria for Systemic Lupus Erythematosus. Arthritis Rheumatol. 2019;71(9):1400–1412.
Shiboski CH, et al. 2016 ACR/EULAR Classification Criteria for Primary Sjögren's Syndrome. Arthritis Rheumatol. 2017;69(1):35–45.
Robson JC, et al. 2022 ACR/EULAR Classification Criteria for Granulomatosis with Polyangiitis. Ann Rheum Dis. 2022;81(3):315–320.
Rudwaleit M, et al. The Assessment of SpondyloArthritis International Society classification criteria for peripheral spondyloarthritis. Ann Rheum Dis. 2011;70(1):25–31.
Taylor W, et al. Classification criteria for psoriatic arthritis (CASPAR). Arthritis Rheum. 2006;54(8):2665–2673.