Rheumatology > Laboratory Tests > ANA (antinuclear antibody)

Laboratory tests

Following is a brief description of some laboratory tests your doctor may order as part of evaluating and treating your rheumatic condition.

Laboratory tests must be interpreted by your doctor in conjunction with a clinical exam, X-rays and other factors. This information may not apply directly to all situations and individuals, and we urge you to discuss your questions about laboratory tests with your doctor.

	[ hide list ] A B C | D E F | G H I | J K L | M N O | P Q R | S T U | V W | X Y Z 25-OH vitamin D ACLA (Anti-cardiolipin antibodies) Albumin  Aldolase ALT and AST ANA (anti-nuclear antibody) ANCA (anti-neutrophil cytoplasmic antibody) Anti-CCP (anti-cyclic citrillunated peptide) Anti-centromere pattern C-RP (C-reactive protein) C3, C4, CH50 (complement tests) CBC (complete blood count) CPK Creatinine Cryoglobulins dsDNA (double-stranded DNA) ENA (extractable nuclear antigens) ESR (erythrocyte sedimentation rate) Hep B S Ag (hepatitis B surface antigen) Hep C Ab (hepatitis C antibody) HLA-B27 Lupus inhibitor assay Lyme titer No information is currently available for section MNO.  Parvovirus titer PTH RF (rheumatoid factor) SPEP (serum protein electrophoresis) TSH Uric acid No information is currently available for section VW.  No information is currently available for section XYZ.

ANA (anti-nuclear antibody)

ANA is a protein that occurs in a wide range of circumstances. It is often referred to as the "lupus test" because it is generally (98 percent to 99 percent of the time) positive in people who have lupus. If all people with a positive test are examined, however, only 10 percent to 15 percent of these people will have lupus. It is a sensitive test, but not a specific one. In practice, a negative test usually (99 percent of the time) rules out lupus as the cause of underlying symptoms.

The ANA may be positive in many other instances, including:

• diseases related to lupus, such as rheumatoid arthritis, Sjogren's syndrome and scleroderma
• autoimmune thyroid disease
• liver disease
• a result of some types of infections
• a result of certain medications
• natural occurrence in up to 20 percent of the normal population

The test is more commonly positive in older people.

ANA is not a measure of disease activity. A higher value does not correlate with more active disease. It is simply a diagnostic test, serving as one piece of information that may lead to a diagnosis. The most important aspects of any evaluation focus on data obtained from the history and the physical examination.