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.
The BUN is roughly one-half of the blood urea (R). Normal human adult blood should contain between 5 to 20 mg of urea nitrogen per 100 ml (5â20 mg/dL) of blood, or 1.8 to 7.1 mmol urea per liter (R). To convert from mg/dL of blood urea nitrogen to mmol/L of urea, multiply by 0.357.