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.
Levels of 24-hour urine creatinine are evaluated with blood levels as part of a creatinine clearance test. Single, random urine creatinine levels have no standard reference ranges. They are usually used with other tests to reference levels of other substances measured in the urine.