Mcv 69, mch 22.6, mchc 32.7 (low), high rdw 16.1. hg/hct normal. rbc 6.45 (high). numbers have declined over past 7 months. iron norm. what is cause?

Need evaluation: All lab results need to be evaluated in the clinical context and the doctor who ordered the test is usually in the best position to do that. It would also help to have the actual results of iron studies. Iron deficiency is a common cause of microcytic hypochromia. Mild thalassemia being another one. If your results are improving, recovery from iron deficiency is a likely explanation.