An **ANA Screening by IFA Diagnostic Test** (Antinuclear Antibody Screening by Immunofluorescence Assay) is the gold-standard blood test used to detect autoantibodies that mistakenly target a patient's own cellular nuclei. Utilizing a fluorescent microscope, laboratory technicians examine human epithelial cells (HeP-2) mixed with the patient's blood serum to look for specific glowing patterns.

This critical diagnostic screening is the foundational first step in identifying systemic autoimmune conditions, such as Systemic Lupus Erythematosus (SLE), Sjögren's syndrome, and rheumatoid arthritis. A positive result provides crucial initial data, prompting further specific autoantibody testing to establish an accurate medical diagnosis.