'16 and Pregnant' Star Whitney Purvis -- Arrested for Stealing Pregnancy Test

"16 and Pregnant" star Whitney Purvis was arrested in Georgia yesterday ... after cops say she shoplifted a pregnancy test from a local Walmart ... and used it in the store.

According to the police report, the 20-year-old MTV star stashed a First Response pregnancy test in a hooded jacket ... and then "took it to the restroom with her and used one."

Purvis allegedly tried to sneak out of the store through a side door ... but she was busted by store security ... who put her under citizens arrest and called local police.

According to the report, the pregnancy test was valued at $15.98.

Purvis was hauled to a nearby police station where she was booked for misdemeanor theft by shoplifting.