(CNN) Before President Donald Trump's physical examination on Friday, Dr. Ronny Jackson had decided he wasn't going to perform a cognitive assessment. Jackson said he didn't feel the test was necessary. But the president requested he be tested, anyway.

"He actively asked me to include that in it so we did," Jackson said Tuesday while speaking to reporters about the results of the president's physical.

Trump has faced several questions about his mental fitness to be president. Last week a group of mental health professionals sent an urgent public letter to the president's doctor requesting he test Trump's cognitive abilities.

At the White House press conference, Jackson said he decided to run what's called the Montreal Cognitive Assessment , known as MoCA. It is a well-known and well-tested assessment that doctors can quickly use to detect "mild cognitive dysfunction," according to the test instructions. "It does rule out the need to do any other cognitive assessment," Jackson said.

The 30-point test takes about 10 minutes and asks the patient to perform a simple batch of memory and mental tasks. The tasks include drawing a line between a number and a letter in ascending order. To test visuoconstructional skills. The patient is asked to draw a clock and put numbers on it, and to draw a cube.

The patient is tested on naming and is asked to give the name of animals drawn on a test page.

In addition, there is a memory test involves the doctor reading a list of five words at a rate of one per second and the patient is asked to remember as many words as they can in any order. The doctor and patient repeat the word test one more time. The doctor will then let the patient know that they will be asked about the words again at the end of the exam.

Next, the exam looks at a person's ability to pay attention. The doctor will say some numbers and the patient is supposed to repeat them in the order that they hear them. The doctor will then ask the patient to repeat another set of numbers backward. The examiner then will read a list of letters and every time they say the letter A, the patient will tap once. Patients' math skills get a work out, as they are asked to count by subtracting seven from 100 and keep subtracting seven until the doctor tells them to stop.

Sentence repetition is the next skill tested. The examiner will read a sentence and the patient is supposed to repeat it. Verbal fluency gets tested as well. A doctor asks the patient to say as many words that begin with a single letter given by the doctor.

Abstract thought is then tested by the doctor, who will ask to explain what a certain pair of words have in common. For example, a patient may be asked what a banana and an orange have in common.

Finally, delayed recall is tested and the doctor will circle back to the list of words they told the patient in the memory test and the patient is asked to remember as many words as possible.

A score of 26 is considered normal. The president did better than that. He aced it and got 30 out of 30.

"The president is mentally very sharp, very intact," Jackson said. "He is fit for duty."

Asked at the White House briefing if any additional cognitive tests should be performed on the president, Jackson said he didn't think so. He thought this particular screening tool was "great" and "I wouldn't recommended doing anything beyond that," Jackson said.

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As far as he knows, Jackson said this is the first time a doctor has performed a cognitive assessment on a president. It has never been done on any other president he has tended to over the years , Jackson said.

"He has gone above and beyond what I would consider a requirement to demonstrate his cognitive abilities," Jackson said.