Which test can confirm a diagnosis of chronic granulomatous disease?

The test that can confirm a diagnosis of chronic granulomatous disease is flow cytometry with dihydrorhodamine. This specific test is designed to assess the functionality of neutrophils, particularly their ability to produce reactive oxygen species (ROS) in response to stimulation. In chronic granulomatous disease (CGD), a genetic disorder affecting the NADPH oxidase complex in phagocytes, patients have a deficiency in their ability to generate these reactive oxygen species, which are crucial for the destruction of bacteria and fungi.

In the flow cytometry test, dihydrorhodamine is used as a fluorescent dye that is oxidized by hydrogen peroxide in the presence of functional NADPH oxidase. If the neutrophils are unable to produce ROS due to CGD, they will not oxidize the dihydrorhodamine, resulting in a diminished fluorescence signal that can be detected by the flow cytometer. This decrease in fluorescence strongly correlates with a CGD diagnosis, making it a valuable tool for confirming the condition.

In contrast, a complete blood count provides general information about blood cell types and may indicate an immune response, but it does not confirm CGD. Serological markers can indicate inflammation or infection but are not specific for CGD