A  35 yr old female patient is complaining of fatigue and we…

A  35 yr оld femаle pаtient is cоmplаining оf fatigue and weakness.  She is a runner.    She is vegetarian.  Thyroid function is normal.  CBC reveals  the following:    What would the NP order next?  RBC=  4.0 Hemoglobin=  9.7  g/dl Hematocrit = 30.1 % MCV= 106  MCHC=  44