I have to say I am troubled by the absence of patient in this model. It seems to me that a patient effect is needed here.
I also think that if you are trying to see which treatment results in the largest change in hematocrit level, you might want to treat this as a "paired" experiment rather than having FOLLOW_UP_HCT and BASELINE_HCT as separate terms in the model, you might want to look at the delta between followup and baseline as the response variable. Or you might want to see if the effectiveness of treatment depends on BASELINE_HCT, that would be different and require a different model than the one you show.
Those are the questions you ought to be asking. What the model is named is somewhat irrelevant, you will have to justify you have the right model.
--
Paige Miller