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Eating disorders - Management
What investigations should I request?

  • If the person has suspected anorexia nervosa, extensive laboratory investigation is not usually required in a primary care setting. Many test results remain normal even with extreme weight loss and are a poor guide to physical risk. However, tests may be useful to rule out complications.
    • Depending on the results of the history and physical examination, consider the following investigations in primary care (seeking specialist advice or admitting to hospital may be more appropriate):
      • Full blood count (may show anaemia), erythrocyte sedimentation rate (ESR), urea and electrolytes (potassium level < 3.5 mmol/L is suggestive of vomiting or laxative abuse), creatinine, liver function tests, random blood glucose, urinalysis.
      • Electrocardiography (ECG). This should be considered for all people with anorexia nervosa, and is strongly advised if there are symptoms or signs of cardiac compromise, bradycardia, electrolyte abnormality, or when the person has a body mass index less than 15 kg/m2 (or equivalent on centile chart).
    • Further tests may be required in more severe cases or to assess complications: calcium, magnesium, phosphate, serum proteins, creatine kinase (or creatine phosphokinase).
  • If the person has suspected bulimia nervosa with frequent vomiting, or is taking large quantities of laxatives (especially if they are also underweight), check fluid balance and urea and electrolytes. Common abnormalities include dehydration, hypokalaemia, hypochloraemia, and alkalosis.

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