Has anyone had any experience like this ?

Hubby had a UTI - sample came back saying there was an infection ( blood in urine was high but no organs were causing it )

He was prescribed Nitrofurtatoin .

Five days after finishing the course he had to do another sample. This came back saying the white blood cells had quadrupled but there was no growth ( infection ) 

Because of his age he is being fast tracked for tests for bladder cancer 

I have read reports that the nitrofurantoin could have caused the high white blood cell result?