Before a doctor starts a treatment, it should be clear which disease is the cause of the patient’s symptoms. In other words, a diagnosis should be made. The examination methods a doctor can use to achieve this are in theory practically limitless, and it is one of the most important tasks of a doctor to make the right choice.
Although the number of tests available is enormous, in practice it is not usually necessary to employ every examination method that may give some extra information on the cause of a complaint. In most instances the patient is already healthy again when the results are coming in.
Overuse of examination methods may not only be a waste of money, it may also even be harmful. Physical damage to the patient or to his or her offspring may be the result of careless use of X-rays. There may also be detrimental emotional side-effects. If many tests are performed, it becomes more likely that during the processing of the results an error sneaks in. On repeating the test it often turns out that nothing is wrong, but in the meantime the patient has had to endure anxious feelings of uncertainty.
Performing many tests can on the other hand give the patient an unjustified impression of security: although he has been given a thorough check-up and a clean bill of health, this does not mean that he might not fall ill in the near future.