I'm African American. Please explain what these results should mean to me. BUN 19, Creatinine 1.28, GFR 46.

Your kidney. Function is slightly lower than normal but not too bad. Stay away from NSAIDs and talk to your doc. Stay well hydrated.
Decreased GFR. May indicate chronic renal disease. More intest include ultrasound and urine protein/ creatinin clearance is needed. Follow up with nephrologist.