Following his latest gaffe on the campaign trail, former Vice President Joe Biden might need to take a "cognitive test," a former White House physician said Tuesday.

During a speech Monday at a South Carolina Democratic Party dinner, Biden mistakenly said he was a Senate candidate instead of a presidential candidate.

"My name is Joe Biden. I'm a Democratic candidate for the United States Senate," he said.

BIDEN ODDLY SUGGESTS '150 MILLION' PEOPLE KILLED BY GUNS SINCE 2007

Dr. Ronny Jackson -- who served at the White House from July 2013 to December 2019 and is now running for a U.S. House seat in Texas -- reacted to the Biden gaffe by suggesting that the 77-year-old candidate take the same cognitive test that President Trump underwent, and "aced," in 2018.

"Remember the cognitive test I gave @realDonaldTrump? The one he aced! Sounds like somebody else might need some testing done!! Scary!!," Jackson wrote on Twitter.

Jackson said in 2018 that Trump was in good physical and mental health based on the conclusions of various tests, including the 10-minute cognitive test, known as the Montreal Cognitive Assessment (MoCA).

The cognitive assessment indicated the then-71-year-old Trump was "healthy," Jackson said.

BIDEN DEFENDS OBAMA ADMINISTRATION'S HANDLING OF RUSSIAN ELECTION MEDDLING IN 2016

Some suggested a 22-second clip tweeted by GOP Chairwoman Ronna McDaniel was altered to make Biden look bad, but a longer three-minute clip showed the presidential candidate wasn't referencing his Senate career before he misspoke. The Washington Post also reported it wasn't altered.

"The president is mentally very sharp, very intact...He's fit for duty. I think he will remain fit for duty for the remainder this term and even for the remainder of another term if elected," Jackson said.

CLICK HERE TO GET THE FOX NEWS APP

After the tests, the White House nominated the former Navy rear admiral to lead the Department of Veterans Affairs, but Jackson withdrew his nomination following allegations he drank at work and improperly gave prescription pills to staff in the White House, according to a 2018 report by the paper.

Jackson is running for a seat in Texas's 13th Congressional District.