For this telescope, the lenses are a concave convex (one side curved out and the other curved in) and a plano concave (one flat side and one side curved in). The plano concave lens is used as the eyepiece with the plano (flat) side facing the eye.
If kidney function begins to decline, BUN and creatinine rise. A normal creatinine depends on muscle mass and age. In general, a normal creatine is 0.5 to 1.2 milligrams per deciliter (mg/dL). A normal BUN is 7 to 20 mg/dL.
384,845 Helpful Votes. A. Blood urea nitrogen (BUN) is a product of metabolism that is excreted in the urine. It is measured in the blood as an indirect measure of how well the kidney is functioning. Increased BUN levels in the blood may indicate early kidney damage, meaning the kidneys aren't effectively excreting BUN.