Diagnosing anorexia 

When trying to determine whether you have an eating disorder, your GP will probably ask questions about your weight and eating habits.

For example, they may ask:

  • if you've lost a lot of weight recently
  • how you feel about your weight and whether you're concerned about it
  • if you make yourself vomit regularly
  • whether your periods have stopped and, if so, for how long
  • if you think you have an eating problem

It's important to answer these questions honestly. Your GP isn't trying to judge you or catch you out – they just need to accurately assess your condition.

Weight and BMI

Your GP will usually check your weight. The weight of a person with anorexia nervosa is at least 15% below average for their age, sex and height.

Your GP may also calculate your body mass index (BMI). For adults, a healthy BMI is 18.5 to 24.9, although sometimes doctors may be concerned if a person's BMI is below 20. Adults with anorexia generally have a BMI below 17.5.

BMI isn't designed for use in those under the age of 18. Special charts known as centile charts need to be used for this group.

Other tests

Your GP may not need to carry out any tests to diagnose anorexia nervosa, but they may check your pulse and blood pressure, take your temperature, and examine your hands and feet to see whether you have signs of any complications of anorexia.

Your GP may also ask you to carry out some simple physical exercises, such as moving between sitting, squatting and standing, to assess your muscle strength.

If you have anorexia, you have a higher risk of developing some heart conditions, such as an irregular heartbeat (arrhythmia). Sometimes an electrocardiogram (ECG) may be needed. This is where a number of small, sticky patches (electrodes) are put on your arms, legs and chest to record the electrical signals produced by your heart.

Your GP may also carry out blood tests to check your general health and the levels of chemicals or minerals such as potassium.

Referral to a specialist

If your GP thinks you may have anorexia, they may refer you to a specialist in eating disorders for a more detailed assessment and treatment, although they will sometimes carry out this assessment themselves.

Read more about treating anorexia.

Page last reviewed: 26/01/2016

Next review due: 01/01/2019