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Wednesday, September 17, 2014
How likely it`s a false positive
I recently had a ana test come back positive, with a reading of 1:1280 with a homogenous pattern. How likely is this result a false positive? I have been diagnosed with fibromyalgia and my RA was 30.1. My sed rate was 40.
A positive ANA @ 1/1280 dilution is usually not a false positive if performed through a competent lab. Positive ANA can occur with Fibromyalgia but generally in titers of 1/320 or less.
If you are less than fifty years old, the ESR would also be abnormal and not attributed to Fibromyalgia. 30.1 IU for an RA test is also abnormal
Larry Houk, MD
Professor of Clinical Medicine and Rheumatology
College of Medicine
University of Cincinnati