Hello, her ferritin levels are indeed within the normal range. Normal ferritin depends on many factors mostly age and other medical conditions. As we age, ferritin increases. Certain inflammatory conditions also raise ferritin levels. For a young female a value close to 16 ng/mL is very common. Menstruation causes iron losses and more iron is needed during puberty. Runners have more iron losses particularly when they run very long distances. Values between 12 and 150 ng/mL are considered normal but I would be more concerned if she had 146 (that is 4 units below the higher normal level) than 16 (4 units above the lower normal level). She could take a low iron tablet every other day (or every 3-4 days) though, without any problems. I hope I ve helped! If you need more information, please ask! Kind Regards!