(CBS) — If the increase of testing wasn’t enough to cause a shortage of tests, a new social media trend involving at-home COVID tests has doctors concerned.

Doctors are worried because they claim people are ruining these tests.

This trend is going viral on the social media app TikTok.

People are getting at-home covid tests from drug stores and using tap water to get a false positive.

The problem with that is putting water on the test does not actually mean the test is inaccurate or that there is covid in the water system.

It actually just means that the test has been altered.

A scientist at the University of Washington said it’s really just misusing a piece of technology.

“Putting tap water on something that is not intended to receive tap water as a sample, that doesn’t mean it doesn’t work.  That just means you didn’t follow the instructions,” Dr. Geoffrey Baird said.

The scientist says this trend is also troubling because it means people are taking tests away from people who need them.

A spokesperson for one of the companies producing these rapid tests says making videos like these during the pandemic is not just irresponsible, but dangerous.