The anti-dsDNA (double-stranded DNA) ELISA is a blood test used to detect antibodies that mistakenly target the body's own DNA. Elevated levels of these antibodies are strongly associated with systemic lupus erythematosus (SLE), an autoimmune disease. The test involves coating a plate with dsDNA, adding the patient's blood sample, and detecting any bound antibodies using an enzyme-linked reaction. A positive result can aid in the diagnosis of SLE and help monitor disease activity.

THE CENTROMERE ANTIBODY (ACA) TEST DETECTS AND MEASURES THE AMOUNT OF ANTICENTROMERE ANTIBODY IN THE BLOOD TO HELP DIAGNOSE A FORM OF SYSTEMIC SCLEROSIS (SCLERODERMA). SYSTEMIC SCLEROSIS IS A GROUP OF RARE CONNECTIVE TISSUE DISORDERS. THE TEST MAY BE USED TO DISTINGUISH BETWEEN THIS AND OTHER CONDITIONS WITH SIMILAR SYMPTOMS. TESTING MAY BE USED TO PROVIDE THE DOCTOR WITH ADDITIONAL INFORMATION IF AN ANA (ANTINUCLEAR ANTIBODY) TEST IS POSITIVE.

U1RNP ANTIBODY IN COMBINATION WITH SMITH ANTIBODY PROVIDES ADDITIONAL SUPPORT FOR THE DIAGNOSIS OF SLE. A POSITIVE U1RNP ANTIBODY ALONE WITH THE CORRESPONDING CLINICAL HISTORY SUPPORTS THE DIAGNOSIS OF MIXED CONNECTIVE TISSUE DISEASE.

SCL-70 ANTIBODIES ARE CONSIDERED TO BE SPECIFIC FOR SCLERODERMA AND ARE FOUND IN NEARLY 60% OF THESE PATIENTS. THEY ARE MORE COMMON IN PATIENTS WITH EXTENSIVE CUTANEOUS INVOLVEMENT AND INTERSTITIAL PULMONARY FIBROSIS AND THEIR PRESENCE IS A POOR PROGNOSTIC INDICATOR.

SS-B/LA IS AN EXTRACTABLE NUCLEAR ANTIGEN WITH ANTIBODIES OCCURING IN PATIENTS WITH SJOGREN S SYNDROME (60%) & LUPUS ERYTHEMATOSUS (15%). THIS ASSAY IS USEFUL FOR EVALUATING PATIENTS WITH SIGNS AND SYMPTOMS OF CONNECTIVE TISSUE DISORDER IN WHOM ANA IS POSITIVE.

SM/RNP ANTIBODY IS DETECTED IN PATIENTS WITH MIXED CONNECTIVE TISSUE DISEASE. ANTIBODIES TO SM ARE HIGHLY SPECIFIC FOR SYSTEMIC LUPUS ERYTHEMATOSUS (SLE) AND WHEN PRESENT ARE CONSIDERED A MARKER ANTIBODY. HOWEVER, THESE ANTIBODIES ARE FOUND IN ONLY 20% OF PATIENTS WITH SLE. RNP ANTIBODIES ARE FOUND IN 45% OF SLE PATIENTS BUT ARE ALSO OBSERVED IN NUMEROUS OTHER DISEASE STATES SUCH AS SJ GRENS SYNDROME, SCLERODERMA AND POLYMYOSITIS. IN SLE, RNP ANTIBODIES HAVE BEEN ASSOCIATED WITH A RELATIVELY BENIGN DISEASE COURSE WITH LOWER INCIDENCE OF RENAL AND CENTRAL NERVOUS SYSTEM INVOLVEMENT.