So is Carbòn's kidney function poor?
In humans we use EP (erythropoetien) in folk with non iron deficient chronic anaemia who have "chronic renal failure" ie reduced renal function.
I can't recall you mentioning it but I may have missed it or is it just hand in hand with Leish?
I think Leish is complex, but aneamia is a clinical manifestation of the disease.
There are graded stages of clinical presentation. To me based on clinical symptoms and biochemistry, Carbon has moderate
general symptoms, but only one and nothing else, coupled with some abnormalities in biochemistry. His biochemistry is not bad, he is really holding his own in what I believe is a key area, his kidney and liver function which has been for the last 18 months fairly stable and at the lower end of normal? is this correct?
But.... aneamia although mild/ moderate can be really debilitating, and for you I can see this being particularly distressing, on top of everything else. Under ideal circumstances, and your excellent care, he just about manages, but more recently he has not, the operation has uncovered the fact that Carbon has been struggling a little in this area.
Breaking this down a bit.
The EPO would not be my first choice, especially as the Leish might be having some effect on white blood cell count because the parasite affects red blood cell production in the bone marrow ... but this is where EPO works it's magic, however it is not generally a good idea to pump bone marrow for production of red blood cells if the reason for the aneamia sits here, and this is part of the Leish disease profile. Unless of course his profile is very, very good. Why EPO now if Carbon has been a aneamic for a while now? I don't know, but it won't do any harm, me personally, I would be interested to understand why EPO and not IV iron.
BUT .... if there are only small changes in the biochemistry, and no other clinical symptoms then I can see where your vet is going with this, meaning give Carbon a bit of EPO, it should work it's magic, BUT this will take a month, maybe less as it is just a boost, and he is producing viable red blood cells (remember the retic test? ). Carbon just needs a bit more right now. Give it a bit of time for Carbon to feel stronger, and he will cope better physically and mentally with a more assertive treatment protocol for his Leish. Now this is really good!
I really would stamp your feet for the Leish treatment, whatever it takes right now.
Phew!!
Now don't get me started on your meds!

Jeez woman!!!