CTD Screen (ANA screen)

The CTD Screen test is designed for qualitative in vitro measurement of IgG antinuclear antibodies in human serum and plasma, as an aid in clinical diagnosis:

Systemic lupus erythematosus (SLE);
Mixed Connective tissue disease (MCTD);
Sjogren's syndrome;
Scleroderma;
polymyositis/dermatomyositis.
Antinuclear antibodies are a special group of autoantibodies that, under certain conditions, begin to produce protein molecules that are an integral part of the main components of the cell nucleus. In other words, the immune system fails and begins to attack the components of its own body.

In these diseases, the body's cells are damaged by immune complexes circulating in the blood. In particular, the nuclear structures of cells are damaged, which leads to the additional production of autoantibodies to structures enclosed inside the cell nucleus. As a result, the formation of antinuclear antibodies occurs, which leads to damage to the genetic material of the cell, as well as to its death.

The test for anti-nuclear antibodies is considered highly sensitive but has low specificity. In almost one hundred percent of cases, it indicates an autoimmune process, provided they are detected in the bloodstream. The low specificity of the test is expressed in the fact that its definition cannot tell the diagnostician exactly which autoimmune disease has developed in this patient, but the very fact that the patient has an autoimmune process gives him the opportunity to conduct additional analysis methods for the final diagnosis.