Nope, THC would only show up in a blood or urine drug screen or toxicology test. With a Pap, they're looking at a smear of cervical cells on a slide under a microscope to see if they see signs of abnormal cell growth that would indicate precancerous or cancerous growths. A Pap smear can also show certain types of infections and/or tissue abnormalities. It won't show HPV, however. That's the human papilloma virus, some types of which cause cervical cancer. It's a good idea for young, sexually active women to get both a Pap and an HPV test.

In my medical microbiology class, we're looking at abnormal, precancerous and cancerous cells from Pap smears right now, among other things.