Dear Marie, Sed rate is a nonspecific test and indicates inflammation. Used as a guide in treatment, ie the nephrologist/internist I worked for in the lab used to use it on his rheumatoid arthritis patients to follow the disease process. It varies as to when it will come back to normal, but I would hope there are other tests run as well. The red cells fall more rapidly due to the plasma proteins effect on them, like fibrinogen and globular proteins(antibodies fit in here). The cells adhere and fall more rapidly as the clumps are heavier. In my lab "everything you always wanted to know..." book- Bakerman, there are about 40 causes of elevated ESR in 6 categories - Infections, hematologic, GI, collagen diseases, renal, and misc(included here is drug hypersensitivity reactions and hypothyroidism, for example)-if you want the list, email me I'll type them all in. I guess what I'm saying is ESR alone wouldn't be too likely to tell you what's wrong, but tells you that inflammation is present, and the amount of inflammation roughly proportional to how elevated the ESR is. Seems like you would be still recovering and fatigued as your treatment didn't end that long ago!! A year til you're fully restored to your energy level doesn't sound unreasonable to me! Wonder if you're "run down" in other ways because of the toll the stress has taken on your body, immune system, and all? It's a shame that your doc won't extend your leave, sounds like you need it. Any chance of getting a lighter schedule for a while when you first go back? Keeping you in thoughts and prayers, Georgeanne Mattise, LLLL, MT(ASCP), mostly MOM! , Scranton, PA