The 50% hemolytic complement test measures the ability of the complement system to lyse red blood cells, thereby evaluating its hemolytic activity. This analysis is crucial for diagnosing and monitoring autoimmune and infectious diseases. We use the Enzyme-Linked Immunosorbent Assay (ELISA) technique to ensure accurate and reliable results. It is important that the sample does not show hemolysis and that elevated heterophile antibodies do not interfere with the results.