Anti-histone antibodies are autoantibodies that are found in 50%-70% of patients with systemic lupus erythematosus

Systemic lupus erythematosus

Systemic lupus erythematosus , often abbreviated to SLE or lupus, is a systemic autoimmune disease that can affect any part of the body. As occurs in other autoimmune diseases, the immune system attacks the body's cells and tissue, resulting in inflammation and tissue damage...

 (SLE) and in more than 95% of patients with drug-induced lupus erythematosus

Drug-induced lupus erythematosus

Drug-induced lupus erythematosus is an autoimmune disorder caused by chronic use of certain drugs. These drugs cause an autoimmune response producing symptoms similar to those of SLE...

. In other words, a test for anti-histone antibodies has a sensitivity

Sensitivity and specificity

Sensitivity and specificity are statistical measures of the performance of a binary classification test, also known in statistics as classification function. Sensitivity measures the proportion of actual positives which are correctly identified as such Sensitivity and specificity are statistical...

 of 50%-70% in detecting patients with SLE and more than 95% sensitivity in detecting patients with drug-induced LE.

An ELISA

ELISA

Enzyme-linked immunosorbent assay , is a popular format of a "wet-lab" type analytic biochemistry assay that uses one sub-type of heterogeneous, solid-phase enzyme immunoassay to detect the presence of a substance in a liquid sample."Wet lab" analytic biochemistry assays involves detection of an...

 for detecting anti-histone antibodies is said to be positive when there is more than 25 units/ml anti-histone antibodies in a blood sample.