From Wikipedia: "Creatinine is a break-down product of creatine phosphate in muscle, and is usually produced at a fairly constant rate by the body (depending on muscle mass).... Creatinine is chiefly filtered out of the blood by the kidneys."
So, if the kidneys are not functioning as well as they should, the levels of Creatinine in the blood rise. So, Creatinine can tell us how well the kidneys are functioning.
Once you are on maintenance hemodialysis, it means that your kidneys are not functioning. This is different from the few sessions that you need to do when you have Acute Renal Failure due to snake bites, accidents etc. When you are on maintenance hemodialysis, it means that you have Chronic Renal Failure (CRF) which means that the kidneys are not going to get back their function.
What is the point in checking Creatinine levels for those with CRF? Are you going to do something if the Creatinine level rises? Or if the Creatinine level falls?
Internationally too, mostly, Creatinine levels are not checked for CRF patients.
Despite this, month after month, most doctors prescribe Creatinine levels for their CRF patients. Patient also get attuned to this and expect to be asked to get their Creatinine levels checked. They are actually shocked when Creatinine levels are not checked!
A lot of these patients are secretly hoping for a miracle. That their Creatinine levels start falling and their kidney function returns. Well, I really don't blame them. But there are other ways to know this. Your urine output would start rising to begin with.
Please correct me if I am wrong on this!
... http://www.kamaldshah.com/2011/11/is-checking-creatinine-really-useful.html