A G6PD test measures the levels of glucose-6-phosphate dehydrogenase (G6PD), an enzyme in your blood. An enzyme is a type of protein thats important for cell function. G6PD helps red blood cells (RBCs) function normally. It also protects them from potentially harmful byproducts that can accumulate when your body is fighting infection or as the result of certain medications. A lack of G6PD may make RBCs more vulnerable to breaking down in a process called hemolysis. G-6-PD deficiency is a sex linked disorder affecting males whereas females are the carriers. If G6PD levels are too low, then RBCs wont be protected from these chemicals. The blood cells will die, leading to anemia.