 [ Symptoms ] can you have a utibladder infection even if urinalysis done by a lab is negative for bacteria  ua also negative for everything else  [ Disease ] hi ok as long as he did not ejaculate at any time and as long as he urinated since last masturbating so there sperm in his pre cum you should be ok but as your getting very near to becoming sexually active its about time to go see your doctor or a women is clinic and think about getting some bc pill protection do hope this helps you good luck