I think my office has fleas

I live in a house with four cats (all indoors) and never see fleas. We fought through two flea issues when they were kittens, but knock on wood have not seen any sights lately. But work seems to be different. Now I'm not saying we have a flea infestation, but it's just odd. Last week I was with a patient and I noticed a tiny bug on my sleeve, and when I picked it off it was a flea (quickly squashed with my pen). Then the other day I thought I saw something, but disregarded it. But to top things off, I was adjusting one of the staff and sure enough there was another one, this time on my pants leg. It jumped when I went to get it (makes me think it's on me and I get itchy, subconsciously). It's not like they're just jumping all over the place, but obviously there's something there. One, it could have come off someone's shoe. But three, I just don't know.