I had a UTI last month. My doctor said he found a lot of white blood cells in my urine and asked me if I vaginal discharge. What does that mean?

Urinalysis. When a urine specimen contains wbcs they may have come from the urine, or the urine may have been contaminated by vaginal secretions or discharge. Your doctor is trying to determine the source of the wbcs. If you gave a clear midstream catch urine it is not likely that they came from the vagina.