Lupus Blood Tests: ANA, Anti-dsDNA and What They Mean

Lupus, or systemic lupus erythematosus (SLE), is a long-term autoimmune condition in which the immune system attacks healthy tissue. The NHS lists joint and muscle pain, extreme tiredness that does not go away however much you rest, and rashes (often over the nose and cheeks after sun exposure) as the main symptoms. Headaches, mouth ulcers and hair loss can also happen. More women than men get lupus, and it is more common in people of African, Caribbean, Asian or Chinese background.

Because the symptoms overlap with many other conditions, blood tests play a big part in finding lupus, but no single result can confirm it. This guide explains the ANA test, anti-dsDNA antibodies, complement C3 and C4, the full blood count and kidney and urine tests, which test to book first, and the symptoms that need urgent help.

Test it in Chiswick: our Antinuclear Antibodies (ANA) blood test costs £99, with your result explained in person by a practitioner. No GP referral needed. Book this test or call 020 4515 0000. Prefer to test at home? A home finger-prick kit is also available, ask us when you enquire, or see our home kit options.

Quick answer

The first blood test for lupus is usually an antinuclear antibody (ANA) test. About 95% of people with lupus test strongly positive, but ANA is also found in many healthy people, especially at low levels and in older age, so a positive result alone does not mean lupus. Anti-dsDNA antibodies, found in about 70% of people with lupus, make the diagnosis highly likely. Complement C3 and C4, a full blood count, kidney function and a urine test for protein help show how active lupus is and whether organs are affected.

Blood tests that can help

ANA (antinuclear antibodies)

ANA is the main screening test for lupus and related connective tissue diseases. Arthritis UK (formerly Versus Arthritis) says about 95% of people with lupus test strongly positive, so a negative ANA makes lupus much less likely. The catch is that ANA is common in people without lupus. NHS guidance from Scotland notes that a low level positive ANA (1:40) is found in 20 to 30% of healthy people and in up to 70% of people over 70, and that clinically significant levels are usually above 1:160. ANA can also be positive in other autoimmune conditions, chronic infections and with some medicines. For this reason ANA is most useful when you have symptoms that suggest lupus. Our ANA test costs £99.

Anti-dsDNA antibodies

Anti-double-stranded DNA (anti-dsDNA) antibodies are much more specific. Arthritis UK says about 70% of people with lupus have them, and a positive result makes lupus highly likely. Levels can rise when lupus is active and fall with effective treatment. Some NHS laboratories test for anti-dsDNA automatically when an ANA is clearly positive. We do not currently offer anti-dsDNA as a separate test, so if your ANA is positive your GP or a rheumatologist can arrange it, along with other antibody tests.

Complement C3 and C4

Complement proteins are part of the immune system and are used up when lupus is active. LUPUS UK explains that a fall in C3 or C4 below normal often indicates a flare, so these tests are mainly used to monitor lupus once it is diagnosed. You can book Complement C3 (£79) and Complement C4 (£79) on their own, and both are included in the Muscle and Joint Screen.

Full blood count

Lupus can lower white blood cells, red blood cells and platelets. Arthritis UK notes that blood counts help show whether the bone marrow is affected, either by lupus or by the medicines used to treat it. Our Full Blood Count costs £59, and our guides to the white blood cell count and platelet count explain the results.

Kidney function and urine protein

Lupus can inflame the kidneys, often without any symptoms until damage is advanced. The NHS says urine tests are used to check for kidney problems, and that regular urine tests are recommended once lupus is confirmed. A simple urine test can show protein or blood in the urine. Our Urinalysis (£19) checks for protein and red blood cells, and our Kidney Health Check (£49) measures creatinine and eGFR. A Urine Albumin to Creatinine Ratio test (£49) is a more sensitive check for protein leaking into the urine. Read more in kidney function test results explained.

ESR and inflammation markers

The ESR rises with inflammation, including in lupus, but LUPUS UK points out that it is not specific to lupus. Our ESR test costs £39, or you can combine it with CRP, ferritin and a full blood count in the Inflammation Check (£79).

Which test should I book?

• A focused start: Antinuclear Antibodies (ANA), £99. The standard first test when lupus is suspected.
• A broader picture: Rheumatology Extended, £179. ANA plus ESR, rheumatoid factor, anti-CCP antibodies, smooth muscle antibodies and uric acid, which helps tell lupus apart from rheumatoid arthritis and gout.
• The fullest view: Muscle and Joint Screen, £129. Complement C3 and C4, CRP, immunoglobulins, rheumatoid factor, kidney function (creatinine, eGFR and cystatin C), liver markers, iron studies, vitamin D, creatine kinase and uric acid. It does not include ANA, so pair it with the ANA test.

None of these panels includes a full blood count or a urine test, so it is worth adding a Full Blood Count and Urinalysis.

What blood tests cannot tell you

Arthritis UK explains that lupus is diagnosed from your symptoms, a physical examination and blood tests together. Diagnosis is usually confirmed by a rheumatologist, who uses classification criteria that combine features such as rashes, joint inflammation, blood count changes, kidney involvement and antibody results. A positive ANA without symptoms is common and is not lupus. Equally, a single normal result does not settle the question if your symptoms continue.

Blood tests also cannot show which organs are affected on their own. Kidney involvement needs urine tests, and heart, lung or nerve symptoms need examination and further tests arranged by your specialist team.

When to see a GP urgently

The NHS says lupus that affects the heart, lungs, brain or kidneys can be life threatening. Call 999 if:

• you have sudden chest pain or discomfort that does not go away
• chest pain spreads to your arm, neck, jaw, stomach or back
• you have chest pain and feel sweaty, sick, light headed or short of breath
• you have severe difficulty breathing, for example gasping or not being able to get words out

Contact your GP, your lupus team or NHS 111 the same day if you have sharp chest pains or new breathlessness, a high temperature, eye symptoms, or you are bruising easily or bleeding from your gums or nose. See a GP if you often get lupus symptoms such as joint pain with rashes and extreme tiredness, as early diagnosis and treatment help.

Frequently asked questions

Can you have a positive ANA and not have lupus?

Yes, this is common. A low level positive ANA is found in 20 to 30% of healthy people and in many older adults, as well as in other conditions. Your result is read alongside your symptoms.

Can you have lupus with a negative ANA?

It is uncommon, because about 95% of people with lupus test strongly positive. If your symptoms strongly suggest lupus, discuss them with your GP or a rheumatologist rather than relying on one result.

What does a low C3 or C4 mean in lupus?

In someone with lupus, a fall in C3 or C4 below normal often means the condition is becoming more active. These tests are most useful when compared with your own earlier results.

Which blood test confirms lupus?

No single test confirms it. A positive anti-dsDNA makes lupus highly likely, but the diagnosis is made by a specialist using symptoms, examination findings and several test results together.

Why do I need a urine test for lupus?

Lupus can affect the kidneys without causing symptoms. A urine test for protein and blood is a simple way to pick this up early, which is why it is repeated regularly once lupus is diagnosed.

Lupus blood tests in Chiswick

Omnia Lifestyle is at 8 to 9 Bedford Corner, The Avenue, Chiswick, London W4 1LZ, a short walk from Turnham Green station (District line; Piccadilly line trains stop there early morning and late evening only) and served by buses 94, E3 and 272. Limited parking is available on request when you book. Every clinic test price includes your sample taken at the clinic, analysis at the Randox accredited laboratory, a practitioner review of your result with you, and a GP feedback report on request. You do not need a GP referral, and most results are back within a few working days.

Useful links: book the ANA test or the Rheumatology Extended panel, browse our autoimmune and inflammation blood tests, or compare every blood test and price. Our guides to blood tests for joint pain and kidney function test results explain related results.

This article is general information, not medical advice. Discuss your results with your GP or practitioner.