Patient Guide

Guide to Autoimmune Blood Tests

Name: Guide to Autoimmune Blood Tests: ANA, RF & Anti-CCP
Creator: Suman Konda
Published: 2026-07-05

Autoimmune diseases are diagnosed with a panel of specific blood tests. Each test targets different antibodies. This guide explains which test detects which disease.

Written by Suman Konda, PharmD, Clinical Pharmacist · Editorial policy · Not medical advice

Last updated: 01 August 2026 · How we check our content

Autoimmune blood tests and what they detect

Test	Primary disease	Sensitivity
ANA (antinuclear antibody)	Lupus (SLE): screening test	95% in SLE
Anti-dsDNA	Lupus: specific, tracks disease activity	70% in SLE
Anti-Sm	Lupus: highly specific	25% in SLE
Anti-Ro (SSA) / Anti-La (SSB)	Sjögren's syndrome, neonatal lupus	~75% in Sjögren's
Rheumatoid Factor (RF)	Rheumatoid arthritis (RA)	70–80% in RA
Anti-CCP	Rheumatoid arthritis: more specific than RF	70–80% in RA, >99% specific
Anti-Scl-70 (anti-topoisomerase)	Diffuse cutaneous scleroderma	~40% in scleroderma
Anti-centromere	Limited scleroderma (CREST syndrome)	~80% in limited scleroderma
ANCA (PR3 / MPO)	Vasculitis (GPA, MPA)	~90% in active GPA
Anti-Jo-1	Polymyositis / dermatomyositis	~25% in IIM
Complement C3 & C4	Low in lupus flares, hereditary complement deficiency	Track disease activity

ANA: the starting point

Why ANA is ordered first

ANA is ordered as the first screening test when an autoimmune condition is suspected. A positive ANA at titre ≥1:80 prompts further specific antibody tests to identify the exact disease. A negative ANA makes most ANA-associated diseases (lupus, Sjögren's, scleroderma) very unlikely. However, some autoimmune diseases are ANA-negative, notably RA, ANCA vasculitis, and anti-Jo-1 myositis.

Complement levels in autoimmune disease

Complement proteins (C3 and C4) are part of the immune system. In lupus, immune complexes consume complement, causing low C3 and C4, especially during flares. Low complement with high anti-dsDNA is a reliable indicator of lupus disease activity and kidney involvement. Complement is normal or raised in RA and most other autoimmune conditions.

Questions to ask your rheumatologist

Which specific antibodies are positive in my case?
Do my antibody patterns point to one diagnosis?
Is my complement low: indicating active lupus?
Do I need further organ-specific investigations (kidney biopsy, lung function)?

Frequently Asked Questions

What is the ANA test used for?

The antinuclear antibody (ANA) test is a screening test for autoimmune conditions such as lupus. A positive result needs interpretation, as some healthy people test positive and further specific antibody tests are often needed.

Do normal autoimmune blood tests rule out disease?

Not entirely: some autoimmune conditions can be present with normal or borderline results, so tests are always interpreted alongside symptoms and examination rather than in isolation.

Why are inflammatory markers checked too?

CRP and ESR measure inflammation and help gauge disease activity in autoimmune conditions, complementing the specific antibody tests used to reach a diagnosis.