Interpretive

Connective tissue diseases (CTDs) are a heterogeneous group of systemic autoimmune diseases characterized by abnormal structure or function of 1 or more connective tissue elements (ie, collagen, elastin, or mucopolysaccharides). Differential diagnosis of CTDs is mainly based on clinical findings but is complicated by the similarity of their symptoms. Therefore, antibodies to extractable nuclear antigens are useful markers for diagnosing or excluding CTDs.

The most prominent CTDs are systemic lupus erythematosus (SLE)—potentially affecting all organs; Sjogren’s Syndrome (SS)—characterized by diminished lacrimal and salivary gland secretions; scleroderma (systemic sclerosis [SSc])—a chronic, progressive dermatosis; limited systemic sclerosis—scleroderma also known as CREST syndrome with a more benign disease course; poly-dermatomyositis (PM/DM)—an acute or chronic inflammatory disease of muscle and skin; and mixed connective tissue disease (MCTD)—a syndrome with features of scleroderma, rheumatoid arthritis, SLE, and PM/DM.

Additional information can be found by clicking on the Connect Tissue Disease Cascade Algorithm link, found under the Resources section on the left-hand side of this page.

In the rare occurence when an ENA panel screen results as positive with all ENA panel analytes resulting as negative, a DSDNA is reflex ordered. The DSDNA is a part of the ANA panel within the analyzer, which is what causes the ENA panel screen to be resulted as positive. This is included for additional diagnostic purposes only.