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There is an association between rheumatoid factor and more persistently active synovitis, more joint damage, greater eventual disability and arthritis. [12] [13] Other than in rheumatoid arthritis, rheumatoid factor may also be elevated in other conditions, including: Systemic lupus erythematosus (SLE) [14] [15] Sjögren syndrome [14] [15]
The false positive rate is calculated as the ratio between the number of negative events wrongly categorized as positive (false positives) and the total number of actual negative events (regardless of classification). The false positive rate (or "false alarm rate") usually refers to the expectancy of the false positive ratio.
The false positive rate (FPR) is the proportion of all negatives that still yield positive test outcomes, i.e., the conditional probability of a positive test result given an event that was not present. The false positive rate is equal to the significance level. The specificity of the test is equal to 1 minus the false positive rate.
False positive readings can be due to various causes: liver disease, high rheumatoid factor, inflammation, malignancy, trauma, pregnancy, recent surgery as well as advanced age. [21] False negative readings can occur if the sample is taken either too early after thrombus formation or if testing is delayed for several days. Additionally, the ...
In a classification task, the precision for a class is the number of true positives (i.e. the number of items correctly labelled as belonging to the positive class) divided by the total number of elements labelled as belonging to the positive class (i.e. the sum of true positives and false positives, which are items incorrectly labelled as belonging to the class).
Nodules are associated with a positive RF (rheumatoid factor) titer, ACPA, and severe erosive arthritis. Rarely, these can occur in internal organs or at diverse sites on the body. [22] Several forms of vasculitis occur in RA, but are mostly seen with long-standing and untreated disease. The most common presentation is due to involvement of ...
For example, IgM-rheumatoid factor (IgM-RF) have been shown to cross-react with ANA giving falsely positive immunofluorescence. [64] Positive ANA as well as anti-DNA antibodies have been reported in patients with autoimmune thyroid disease.
Cross-reactivity, in a general sense, is the reactivity of an observed agent which initiates reactions outside the main reaction expected.This has implications for any kind of test or assay, including diagnostic tests in medicine, and can be a cause of false positives.