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.
Some medicines are processed by the kidneys or can cause kidney damage as a side effect. The BUN test may be done to be sure you have normal kidney function before you start taking these medicines. What does the test result mean? The normal range for BUN is 7 to 20 milligrams per deciliter (mg/dL). The normal range may vary slightly from lab to lab. Normal ranges are usually shown next to your results in the lab report. Your BUN level may be higher than normal because: Your kidneys aren't working well.