Autoimmune Testing: Factors That Interfere With ANA
What is ANA?
ANA stands for Anti-nuclear antibody. ANA is a great screening test for many common autoimmune diseases.
Testing for autoimmune disease can be confusing, where multiple autoantibodies can be present in one autoimmune disease.
Click here for more about ANA and how we use this test to assess for autoimmune disease.
Have a High ANA?
Anti-nuclear antibodies (ANAs) are describing a diverse group of antibodies that react against nuclear, nucleolar or perinuclear antigens [1]. The image below shows the basic cell structure, including the nucleus.
Factors Affecting the ANA Test
Certain factors can cause false-positive ANA tests. Sometimes a patient may present with a high ANA and the rest of their clinical picture don’t match. It’s important to realize there are are several factors which may falsely elevate your ANA.
The following drugs can cause false positive ANA results [1]:
- Acetazolamide
- aminosalicylic acid
- chlorprothixene
- chlorothiazides
- griseofulvin
- hydralazine
- penicillin
- phenylbutazone
- phenytoin sodium
- procainamide
- streptomycin
- sulfonamides
- tetracyclines
Some drugs can cause false negative ANA results [1]:
- steroids
