DD is always shattered, so she recently had blood tests. The results came back that all was fine except for low iron (ferritin), but not anaemia as her blood count was fine. Apparently the lab had written that the results are unreliable in children but when I asked what the values were and what it meant, the GP said that in an adult, her levels would be considered below normal 
So I'm really confused now - can anyone explain what this means? Shoudl I be concerned about the low ferritin? Why test for ferritin if the results are meaningless?