Since July, my eGFR has steadily decreased. 59 (July), 59 (December), 57 (February), and now 54 (March). Labs reveal no
proteinuria, hematuria, etc. No fever. No other signs of infection. No consistent urinary symptoms. Positive CVA tenderness
sign in January, and achy (not colicky) pain for months above left flank area, though now decreased. Renal ultrasound was
unremarkable aside from "moderately small" kidneys bilaterally (nephrologist said this was insignificant since I am
small-framed). Urine albumin/creatinine was normal. My BMI is about 19. I haven't been exercising much at all due to not
feeling well, do not consume excess protein, and have labs drawn fasting (as instructed).
Nephrologist said, "It's not your kidneys." Then what is it?
What could cause decreasing eGFR with this medical history and current clinical profile?
Other labs are OK, but my PCP is somewhat indirect, and orders a comprehensive metabolic panel alone for almost everything.
Sometimes lipids, urinalysis or CBC, but nothing specialized.