Food Poisoning in Adults - Diagnosis

Authored by Dr Mary Harding, 02 Jun 2016

Patient is a certified member of
The Information Standard

Reviewed by:
Dr Laurence Knott, 02 Jun 2016

Most people will recognise food poisoning from their typical symptoms. If symptoms are mild, you do not usually need to seek medical advice or receive specific medical treatment.

However, in some circumstances, you may need to seek medical advice when you have food poisoning (see below about when to seek medical advice). The doctor may ask you questions about recent travel abroad or any ways that you may have eaten or drunk contaminated food or water. The doctor will also usually check you for signs of lack of body fluid (dehydration). They may check your temperature, pulse and blood pressure. They may also examine your tummy (abdomen) to look for any tenderness.

Your doctor may ask you to collect a stool (faeces) sample. This can then be examined in the laboratory to look for the cause of the infection. A stool sample is not always needed. Your doctor is likely to suggest one in certain situations, such as:

  • If you have recently been abroad.
  • If you are very unwell.
  • If you have blood or pus in your stools.
  • If your diarrhoea is not settling after a week.
  • If you have recently been in hospital or had antibiotic treatment.
  • If you have another medical condition, particularly one which affects your immune system.
  • If the doctor is not sure you have food poisoning or a gut infection (gastroenteritis).
  • If your job involves handling food.

The reason a stool sample is not always needed is that in many cases knowing what germ you have does not make any difference to the treatment you need. Most cases of food poisoning get better on their own even before the stool test result is back.

If you are very unwell, you may need admission to hospital. If this is the case, further investigations may be needed such as blood tests, scans or a lumbar puncture. This is to look for spread of the infection to other parts of your body.

If you think your infection may have come from food at a particular restaurant or shop then inform your local Environmental Health Office. (Find them via the Food Standards Agency website's Report a food problem page.) This is so that the business can be checked out by environmental health officers. Further actions may be taken if there is a problem with their food hygiene practices. This will hopefully help to reduce the chance that other people will get food poisoning. If your doctor suspects or confirms that you have food poisoning, they are also required by law to report this.

Further reading and references

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