Otherwise, if furnace flue is being abandoned because no longer needed, I would require the top be removed and replaced with a domed galvanized metal cap to keep insects and maybe rodents from taking up residence or using it as a nut cache - cost probably about $50-75 additional.
The creatinine levels in both urine and blood are determined and compared. Normal creatinine clearance for healthy women is 88-128 mL/min. and 97 to 137 mL/min. in males (normal levels may vary slightly between labs). Blood urea nitrogen (BUN) level is another indicator of kidney function.
1 A creatinine urine test evaluates how well your kidneys are working by measuring the amount of creatinine in your urine.  A urine 24-hour volume test is the most common type creatinine urine test. Since the urine 24-hour volume test simply involves urination, there are no associated health risks or side effects.