Opks and UTIs

Hi everyone, I have a question about opks. I used them for two months this last year and I got a uti because I was told to hold my urine for four hours and not drink anything before I tested. I stopped using them because I didn't want to get another uti. We still have not achieved pregnancy and I was wondering if anyone has used the opks and not held their urine for four hours? Will they still accurately predict an LH surge if you only hold your urine for an hour or two instead of four?