Tickled patient reveals the VERY simple 'algorithm' his doctor uses to distinguish between a case of the flu and a common cold

THIS doctor's hilarious flu chart reveals the very simple way to tell if you've got the flu or just a cold.

US radio DJ John Richards shared the diagram – titled “My Flu Algorithm” – on Twitter, leaving social media users in stitches.

Readers are asked if they feel like they have been hit by a train.

If they answer “no”, they are told they don’t have the flu.

For those who answer yes, the hand-written note – which Richards calls “flu info from a literal doctor” – then asks if they have actually been hit by a train.

Those who answer no are then told they have the flu – while those who reply yes are told they have been hit by a train.

The flu and a common cold are both respiratory illnesses but they are both caused by different viruses.

On the whole, flu symptoms are more intense than those caused by the common cold.

People who are suffering from a cold are more likely to have a runny or stuffy nose.

It usually takes between one and three days for flu symptoms to develop after catching the virus.

In most cases people feel better after a week.

The NHS explains that the main symptoms include a fever of more than 38C, a chesty cough, headache, tiredness and aching muscles as well as a sore throat, runny nose and sneezing.

Some people can also experience nausea and vomiting, diarrhoea or joint and limb pain.