What causes glucose, bun and creatine numbers to be high?

Different things. Glucose high mean high blood sugar depend on if it was fasting or not or how high it could mean you might be diabetic bun and creatinine are the kidney blood test if they are abnormal either you are dehydrated or you could be having kidney problem the combination of all together if you are diabetic and you are having kidney problem could be a red flag for something serious check with your doctor.