ANA (antinuclear antibodies)

What is ANA (antinuclear antibodies)?

Your immune system makes antibodies against things that do not belong in your body. In autoimmunity that goes wrong and it makes antibodies against parts of your own cells. Antinuclear antibodies, ANA, are directed against parts of the cell nucleus: the DNA itself, the proteins around it and the machinery the cell uses to divide. They occur in systemic autoimmune diseases, in which the immune system affects several organs at once, such as lupus, Sjögren's syndrome, scleroderma and mixed connective tissue disease. The test places your blood on cells and looks whether antibodies stick to the nuclei. The result is therefore a word, negative or positive, and not a concentration with a unit. With a positive result the blood is diluted step by step until the staining disappears, and the last dilution at which staining was still visible is the titre: a titre of 1:80 means the blood still stained when diluted eighty times, and the higher the second number, the more antibodies there are. In addition the pattern of the staining is described, which gives a clue against which part of the nucleus the antibodies are directed. There is no band and no unit. Negative is the usual result. Which titre counts as positive is decided by the laboratory that runs the test, usually from 1:80; a low titre occurs in about one in eight healthy people, and that share rises with age and is higher in women.

Why is ANA (antinuclear antibodies) relevant?

ANA is the sieve at the start of the work-up of a systemic autoimmune disease. Anyone with joint pain in several joints, a rash that worsens in the sun, lasting tiredness, dry eyes and mouth, or fingers that turn white and blue in the cold gets this test as the first step. In lupus the ANA is almost always positive, so a negative result makes that diagnosis very unlikely, and that is the strongest side of the test. The second reason is that a positive ANA sets the direction of what comes next. The pattern and the titre say which follow-up tests make sense: antibodies against double-stranded DNA in lupus, against specific nuclear proteins in Sjögren, scleroderma or mixed connective tissue disease. Without the first sieve you would have to measure all of those at once. The honest limitation is that the test proves nothing on its own. About one in eight healthy people has a low titre, more often with age and in women, and an infection, some medicines and a thyroid inflammation also make the ANA positive. A positive ANA without complaints is therefore usually a finding without consequence, and the test does not belong in a panel for anyone who has no complaints; without fitting complaints it mainly produces worry.

ANA (antinuclear antibodies) decision limits

There is no band to set side by side for ANA, and that is not missing data here but the test itself: the result is a word. Negative is the usual result. If a number is given, it is a titre, the dilution at which the test still stained, and not a concentration; which titre counts as positive is decided by the laboratory that ran the test, usually from 1:80, and none of the labs publishes a limit for it. A positive result means the antibodies are there, not that there is a disease: about one in eight healthy people has a low titre. A negative result makes lupus very unlikely, but does not rule out every autoimmune disease.

ANA (antinuclear antibodies) high or low: what it means

Look first at the word and only then at the number. Negative is the usual result: the test found no antibodies against your cell nuclei, and a systemic autoimmune disease such as lupus is thereby very unlikely. A negative result does not rule out every autoimmune disease, because rheumatoid arthritis and most autoimmune thyroid and bowel diseases have their own antibodies, but for the diseases this test exists for, negative is reassuring. A positive ANA means the antibodies are there, and the question is what that is worth. In order of how often it occurs: antibodies without complaints, a low titre in someone who is otherwise healthy, which occurs in about one in eight people and usually remains a finding without consequence; your age, because the share of positive results rises with the years without there being more disease; a systemic autoimmune disease such as lupus, Sjögren or scleroderma, usually with a high titre, a specific pattern and fitting complaints; and medicines, such as some blood pressure medicines, antibiotics and medicines against heart rhythm disorders, which give a positive ANA that disappears after stopping. The higher the titre, the more likely it is more than chance. What you do about it: with a positive ANA without complaints nothing, except remembering that you have it; repeating is pointless, because it usually stays positive and that changes nothing. With fitting complaints a follow-up with a rheumatologist belongs with it, with the specific antibody tests that fit the pattern, and with a look at kidneys, blood count and inflammation values. What you can do yourself if an autoimmune disease is found is keep the inflammatory pressure low: not smoking, because smoking worsens almost every autoimmune disease, protection from sunlight in lupus, enough sleep and exercise, and following the medication schedule. Always read ANA beside your complaints, because without complaints a positive result says little, beside the titre and the pattern, which say how strongly and against what, beside rheumatoid factor and anti-CCP if the question is about the joints, and beside CRP and ESR, which say whether an inflammation is at play.

How does an ANA (antinuclear antibodies) blood test work?

Referral

Not needed to have the test done, but wise to have it done only with complaints: ANA is the first step in the work-up of a systemic autoimmune disease and not a broad sieve for anyone who has no complaints.

Fasting

Not needed. Antibodies do not move with what you ate.

When

With complaints that fit a systemic autoimmune disease: joint pain in several joints, a rash that worsens in the sun, dry eyes and mouth, lasting tiredness or fingers that turn white and blue in the cold. Not during an infection, because that makes the ANA temporarily positive.

The draw

One tube of blood from a vein in your arm. Your report will show a word, negative or positive, and with positive usually a titre and a pattern; no concentration with a unit.

Repeating

With a positive result without complaints no, because it usually stays positive and that changes nothing. With complaints no repeat follows but a follow-up: the specific antibody tests that fit the pattern.

Where to draw

You can draw at 250+ locations near you, no referral needed. See the locations

Educational information only, not medical advice. Consult a healthcare professional for clinical decisions.