Yes, "labb" is used colloquially in the same way.
Ett labb, labbet
What you do inside the lab is "en laboration", abbreviated "en labb". NB the different gender; "ett laboratorium" is abbreviated "ett labb". Abbreviations normally take the same gender as the original words.
Thanks, Emil for your above clarification ett lab, labbet, labb, labben. Doing the course on my smartphone I am forced to learn these four forms of a noun from different fragments scattered all over the lectures, which is for me a very unefficient and unsystematical way of learning a language, not being a child anymore. Same for the forms of adjectives and other things. I wish someone had told me to use the PC version, with grammar and word lists. Being a supposedly thorough and methodical German :);) I will finish the last lectures and then take a book to fill in the gaps before we are heading off to Sweden this summer. Uff, I had to say this before I finish!!
Unfortunately, the words feature is only unoffically available for Swedish on desktop as well, and though you do get the opportunity to read the lesson notes, the way of learning you describe is how Duolingo intends for you to learn. I don't always agree with that policy, and I think it could be improved, but that's just how it is.
Can laboratori also refer to the lab? Like what you do inside of the laboratory?
So do you say: ett laboratorium, två laboratorium; det här laboratoriet, de här laboratorien?
Ah, I should have know: ett museum - museet två museer - museerna I presume all words with -um work this way?
Well, most of them at least. "Centrum" is a bit tricky with different possibilities.