The symptom checker results show a list of possible conditions, not an actual diagnosis. Consult your doctor if you are concerned.

Enter more symptoms for more accurate results, starting with your most severe symptom. Look through a list of common symptoms.

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If you’re feeling under the weather but aren’t sure what it could be, an online symptom checker can help you identify whether you need to seek immediate medical attention.

Online symptom checkers are calculators that ask users to input details about their signs and symptoms of sickness, along with their gender, age and location. Using computerised algorithms, the self diagnosis tool will then give a range of conditions that might fit the problems a user is experiencing. They can also advice someone whether to seek advice from a healthcare professional and the level of urgency in which to do so.

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 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 in a tab called ‘red flags’. 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.

What’s the difference between a sign and a symptom?

‘Sign’ and ‘symptom’ are often used interchangeably, but if we’re going to be pedantic, they do actually mean different things.

If you’re feeling ill it might not be immediately obvious to somebody looking at you that you’re sick. For instance, if you’re experiencing pain, fatigue or dizziness, only you know what that feels like. These are symptoms - which can only be described by the person experiencing them.

Signs, on the other hand, can be observed by an outsider too. For example, indicators to other people that you’re unwell, such as: sweating, sneezing or looking pale. Or, things that can be measured, such as a high blood pressure reading or a fever determined with a thermometer, count as signs.

How safe and accurate are symptom checkers?

Most doctors agree that online symptom checkers are 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 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.


This symptom checker is provided by Isabel Healthcare Limited. Isabel Symptom Checker ("Isabel") and any content accessed through Isabel is for informational purposes only, and is not intended to constitute professional medical advice, diagnosis or treatment. EMIS shall be in no way responsible for your use of Isabel, or any information that you obtain from Isabel. You acknowledge that when using Isabel you do so at your own choice and in agreement with this disclaimer. Do not ignore or delay obtaining professional medical advice because of information accessed through Isabel. Seek immediate medical assistance or call your doctor for all medical emergencies. By using Isabel you agree to the terms and conditions.

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