My recent labs have included low RDW 11.3 (low=11.5) and low MPV 7.3 (low=7.5)... I have Crohn s disease and have been having tachycardia, palpitations, shortness of breath on exertion, and anxiety / panic attacks. According to my vitals I have had tachycardia since Jan. 2015, but none of the other symptoms. They all appeared in November at the same time as these levels being lower. I have been on steroids for 14 months at 20mg now tapering (currently at 1.25mg). Also on Remicade, Lomotil, and Nortiptyline. Could I have low B12? It seems to include most of my symptoms.