in my husband's KFT(kidney function test)....BUN urea nitrogen serum is 22.01.....is this ok ??

A. Results of the blood urea nitrogen test are measured in milligrams per deciliter (mg/dL) in the United States and in millimoles per liter (mmol/L) internationally. In general, around 7 to 20 mg/dL (2.5 to 7.1 mmol/L) is considered normal.