Newer tests include the percentage of hypochromic erythrocytes, reticulocyte hemoglobin content (CHr), and sTfR. It should be added that a therapeutic trial iron has been proposed as a convenient method to diagnose iron deficiency. This is a reasonable approach in otherwise healthy populations, such as teenage girls and pregnant women, at high risk of deficiency. However, in most clinical settings, it is preferable to make a definitive diagnosis at the outset.