Episode 20 of Grey's Anatomy's ninth season airs on ABC Thursday and viewers will get the answer to the question regarding Meredith Grey's faith: will see develop Alzheimer's like her mother Ellis Grey?

In last week's episode, Can't Fight This Feeling, Grey told Miranda Bailey she wants to test her predisposition to Alzheimer's with the help of Bailey's new genetic mapping technology. In Thursday's episode, She's Killing Me, we will get the results. In ABC's synopsis of the episode, the network stated that Meredith and Derek Shepard will receive "some unsettling news," and many are assuming it has to do with her Alzheimer's testing.

A preview clip for the episode, shown below, shows that Meredith does in fact test positive for more than one genetic marker for Alzheimer's, though details of exactly which markers are not specified.

In the clip, Bailey is shown trying to keep results from Meredith at first. She asks her to answer a questionnaire, trying to stall. Bailey also said she could not get a "clear read" off of Zola's sample.

"This test gives us a tons of information. Some of it's clear and some of it isn't, so we don't want to jump to anything without careful consideration," Bailey explains, but Meredith keeps cutting her off, asking for the final result.

Meredith says, "Bailey, you're my mentor and my friend and i respect your work, but I'm telling you - if you don't answer my question, I will punch you in the face."

Bailey then tells her, "You have tested positive for more than one of the genetic markers for Alzheimer's."

She's Killing Me, part of Grey's Anatomy season nine, airs on April 4 at 9 p.m. ET on ABC.