urine test. - any practice nurses who out there?

[Flowertop]

Hi, when I was having a well woman check the nurse 'dipped' something into my urine sample and detected blood. She said she was going to send it away and then gave me a bottle to provide another sample in a few weeks so she could dip again. Since then results from lab were negative. My question is if negative why do I need to provide nurse with anothe sample. Surely the lab would have detected a problem.

I'm not a medical professional but my doctor found blood in my urine during a dip test. She sent another sample to the lab but they found nothing. However, she said she wanted to do another test to satisfy herself that there was no longer any blood in my urine.

HTH.