Used as a biomarker for iron deficiency, especially in detecting early stages of iron deficiency anemia when traditional markers are still normal. It accumulates in red blood cells when iron is insufficient for heme synthesis, making it valuable in clinical and public health screening. Also applied in food fortification programs to assess population-level iron status. In addition, it has been studied for its potential in photodynamic therapy due to its ability to generate reactive oxygen species under light exposure. Used in research settings to investigate heme metabolism and erythropoiesis disorders.