In my humble opinion your blood loss should be measured in too ways. One is from a subjective point of view, meaning how do you feel? Do feel tired, are you having heart racing, etc...? The second way is to having your blood loss measured objectively with a Complete Blood Panel which will give you very clear answers as to how your blood loss is really effecting your body. It will give you measurements of your RBCs, Hg (heamoglobin), platelets, MCH, MCHC which will really give you an accurate idea of how your body is reacting to this chronic loss. There can come a point where one will need a blood transfusion to keep up.
In the end if it effects you in any way objectively or subjectively the blood loss is too much. It means your UC is not being handled properly and different care needs to be done.
Hope this helps.
MyUC