Making a Pig's Ear of it.

Because I have worn glasses since I was five years old I am very familiar with the eye-sight test. One of the aspects of the test, which hasn’t changed over the years, is the section where you wear an empty frame while the optician inserts lenses of different strengths asking questions like "Is this one clearer, or is this one?" I once suggested that I was giving contradictory answers to which the optician agreed. She added that it was her skill and experience that enabled her to identify the correct lens strength from these contradictory responses. Speaking to other opticians since, I have learnt that this is precisely the reason that the correct lens strength cannot be determined by a machine.

Doctors are similar. They listen to your description of your symptoms and then ask searching questions to determine the probable cause of your illness. The difficulty is that different illnesses have this irritating habit of presenting very similar symptoms and it is the Doctor's skill and experience that enables him to determine the underlying cause of your discomfort.

Yesterday, the swine flu hot line was launched. The hot line is manned by people who are not Doctors. They have a series of questions to ask to determine whether you have swine flu. It is an automatic process that cannot possibly replace a Doctor. There is always the possibility that someone with a different illness could be misdiagnosed. It was predicted here and it has already occurred, see here