Why do I still have nitrates and leukocytes on my urine dipstick when the urine culture is negative?

Many reasons. There are many possible reasons why a urine culture is negative but the nitrates and leukocytes are positive. 1. If your taking antibiotics then that would prevent growth of the urine culture. 2. The leukocytes and nitrates do not represent an actual bacterial infection but other viral, chemical, or environmental reasons for a positive result 3. Dipstick test or urine culture tests are false.