Symptom checker

How to get started

• Begin by entering symptoms that best describe your current condition.

• Symptoms can be entered in your own words or chosen from the list of matching suggestions; select the most appropriate.

• If no suggestions appear, double-check your spelling or use different words to describe your symptoms.

• Submitting a symptom leads to a page that displays a list of potential diagnoses, which can be accessed by tapping or clicking on them to get information.

Best practices

• Use medical language as much as possible when entering symptoms. For example, "abdominal pain" is better than "belly hurts".

• Start with entering the area of the body affected, then the symptom. For example "abdominal pain" instead of "pain in abdomen".

• Use text, not numbers. For example, enter "high blood pressure" instead of "BP 150/90".

• Enter only abnormal test results, for example "low iron". Do not enter tests that you have been told are normal.

• If you have recently travelled abroad, you may be affected by a disease more common in that region. In this case, select the country where you were travelling.

How do I know if I’m sick?

Using an online symptom checker is simple. For instance, you might be a 45-year-old-woman from the UK who is currently experiencing a headache, a fever and a sore throat. Inputting this information into the symptom checker will give you some likely ‘common’ diagnoses. These include: strep throat, tonsillitis, sinusitis and flu.

But the self-diagnosis calculator will also give a list of rarer but more serious diagnoses tagged ‘Urgent’. Here you’ll find links to our patient information leaflets about much less common conditions, such as temporal arteritis, meningitis and toxic shock syndrome. If, after reading the information, you think one of these serious conditions could apply to you, you should seek medical advice immediately.

Patient’s symptom checker

Patient uses a self-diagnosis tool called The Isabel Symptom Checker. It was released in 2012 by chief executive officer and co-founder Jason Maude, and has been continually improved and updated ever since.

In 1999 Maude’s young daughter, Isabel, contracted the life-threatening conditions necrotising fasciitis and toxic shock syndrome. But doctors had diagnosed her with nothing more than a severe case of chickenpox. Luckily, despite some close calls and a two-month stay in hospital, Isabel pulled through. Her diagnosis had been missed by doctors because it was so rare.

So Maude set about creating a tool that would bring up a list of all the possible diseases for an entered set of symptoms, no matter how unlikely. His aim: to ensure that in future more dangerous conditions would not be missed by healthcare professionals and parents would not have to go through what he and his wife experienced.

How safe and accurate are symptom checkers?

Most doctors agree that online symptom checkers are valuable: they can encourage people with life-threatening symptoms to seek urgent attention, potentially saving lives. They’re also useful for reassuring patients who may have sought urgent care when they didn’t need to. However, one research study suggested that online symptom checkers tend to be over-cautious, which could lead to an increase in unnecessary appointments, rather than a reduction. Another piece of research from the United States found that doctors are twice as likely to make a correct diagnosis as online symptom checkers.

While these self diagnosis tools can certainly be useful for determining whether a trip to hospital is necessary, they can’t match the expertise of an experienced health professional.