My BUN result is 21, and BUN/CREATININE ratio is 29. I have struggled with Vit D and B12 deficiencies in the past. Should I be concerned?

While your BUN. (blood urea nitrogen) is slightly high (usual normal is up to 20), your BUN/creatinine ratio is higher at 29 (usual normal is also up to 20). An increased ratio may be due to a condition that causes a decrease in the flow of blood to the kidneys such as dehydration or congestive heart failure. Vitamin D or B12 levels should not impact this. Discuss with the doctor who ordered these tests for you.