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Br J Gen Pract. 2010 April 1; 60(573): 293.
PMCID: PMC2845491

Diagnostic safety-netting

Congratulations on your article that is very helpful for developing countries.1 As you have mentioned, undifferentiated presentations and uncertainty in management are an important issue to GPs. I wish to include three clear situations:

  • You may see the obvious ‘redflag’ that you will not miss or take a chance with. A middle-age female who presents with sudden onset, severe headache that she has not experienced before and no physical signs detected. This may be a subarachnoid hemorrhage even though you cannot exclude a first attack of migraine. Do not take any chances, play it safe.
  • May expect a ‘redflag’ later. The article1 mentioned that in some situations the time period is certain; for example, head injury leading to subdural hematoma. I do not agree as the safety-netting period may depend on so many factors. Site of injury, severity of injury, and age. Another classic example: a patient with heartburn has a normal ECG suggestive of gastroesophageal reflux disease. As you are aware 50% of ECGs in the first 6 hours could be normal. You may repeat after 6 hours and may rule out an infarct. I have seen a frank MI showing in the ECG even after 24–48 hours.
  • A patient who has typical features suggestive of IBS has a diagnosis card indicating the same. The same patient is diagnosed with colonic carcinoma after 6 months. Have you misdiagnosed or have they developed a colonic carcinoma later?

These are questions we have to answer in general practice.


1. Almond S, Mant D, Thompson M. Diagnostic safety-netting. Br J Gen Pract. 2009;56(568):872–874. [PMC free article] [PubMed]

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