Dihydrorhodamine (DHR) test is a specialized assay used to evaluate the function of white blood cells, particularly neutrophils, in producing reactive oxygen species (ROS) essential for fighting infections. This analysis is a key tool for diagnosing immune system disorders such as Chronic Granulomatous Disease (CGD). The test is performed using flow cytometry to precisely analyze cell activity. It helps determine the efficiency of the immune system in patients experiencing recurrent infections or other immune-related issues.