Photo Credit: Lewis Cole
I remember in vet school, one of the clinical instructors said, “Treat the patient, not the numbers.” One of our patients was a miniature schnauzer with pure red cell aplasia–her bone marrow wasn’t making red blood cells. Her hematocrit hovered around 8%!! Yet, besides tiring easily, she seemed perky and continued to eat well. We were discussing when to do a blood transfusion, and someone asked how low does the hematocrit have to be before you would transfuse her. But there is no absolute number–it depends on the patient. Her anemia progressed slowly over time, so her body had time to compensate for the decrease in systemic oxygen delivery. (Side note: this is also the patient I will never forget because–sad part warning–she died mid-venipuncture to collect a tiny sample of blood. She literally couldn’t part with another drop of blood! Her final hematocrit was 5%.)
Another version of this saying goes, “Treat the patient, not the disease.” I can especially see how this rings true in human medicine. You go to the cardiologist for your heart. You see the ear/nose/throat doctor for your sinuses. You talk to a urologist about cystitis. You can end up on so many medications for this and that, with none of the doctors seeing the big picture: the person as a whole.
I try hard to not get too carried away with numbers, but I’m sure there are times when I could do a better job. For example, don’t we get all up in arms about elevated Alk Phos levels? I mean, how many clinically normal patients do you see with an Alk Phos greater than 800 and otherwise normal blood work? For me, it’s probably once a month or so? I do think further testing is warranted, to check for disease that is not yet clinical but may become so.
Going back to my first example of gradual-onset anemia. Take the flip-side. If you were presented with a patient who was white as a sheet and lethargic with a history of possible rat bait exposure, and the hematocrit was 20%, would you recommend a transfusion?
The Learning Vet
thelearningvet 
This seems to apply to low BG too. If a cat is eating a low carb canned diet and the owner is home testing, the cat is in remission where there are no signs of hypoglycemia, I don’t think it’s a problem. Human BG meters test lower that pet meters, and possibly even lower (less accurate) when the BG is lower. Also found out the BG reading was lower if the cat was confined compared to being more active. Testing other nondiabetic cats in household eating a low carb canned food resulted in BG somewhere around 60 (3 mmol).
Then the vet recommends feeding 300 calories a day which would likely have put fat back on the cat (he was formerly obese, so all those fat cells are still on board) and possibly made him diabetic again. Can you imagine a human doctor telling a 140 lb formerly obese patient managing their diabetes with diet to eat 3,000 calories a day? Since it was their way or the highway, we found a new vet who doesn’t think like that.