The widely accepted definition, also endorsed by the European Society of Cardiology (ESC), defines ID as a ferritin level below 100 μg/L or ferritin levels between 100 and 300 μg/L with a transferrin saturation (TSAT) below 20% [5]. However, it should be noted that ferritin, despite being a commonly used biomarker for detecting iron deficiency, can be significantly influenced by factors like inflammation, infection, and malignancy. The gene discussed is TF; the disease is infection.