Testing for Candida seems to be very hard and even controversial. I don't rely on tests anymore until someday someone comes up with a reliable one.
Until then, your body is the best indicator. Yeast overgrowth symptoms are what make you feel bad and don't have any organic explanation. Sweet cravings and digestive disorders from an unknown nature are good indicators.
So, to answer your question, I will say yes. Even if conventional tests show nothing wrong you may still have an aggressive form of Candida sticked to your gut walls and not showing up in your stools nor in your blood.