It may not be possible to diagnose your condition with one stand alone test. Many conditions can cause similar symptoms. For example, a fever, headache, or weight loss could be caused by a variety of illnesses. In these scenarios, your doctor will often use a technique called a ‘differential diagnosis’. 

Differential diagnosis explained

A differential diagnosis involves making a list of possible conditions that could be causing a person’s symptoms which will be based on what the patient describes as their symptoms and any physical examination findings.  After which, the doctor will try and narrow down the possibilities and reach the most likely diagnosis. They will take a full medical history, possibly perform a more in-depth physical exam or order one or more diagnostic tests if appropriate (for example, blood test, urine test, scan/x-ray). Your doctor may also refer you to a specialist if they themselves do not have the correct expertise to diagnose your condition.

It is not uncommon for it to take time for the true diagnosis to be reached and you may see more than one doctor before you receive your diagnosis and treatment plan.

If you aren’t satisfied with a diagnosis

If you have concerns about your diagnosis, you should share these with your treating doctor. You may also seek a second opinion.

In some unfortunate cases, a correct diagnosis has been missed or alternatively a diagnosis has been made much later that it should have. In some very unfortunate cases this can result in a death or life changing injury, particularly in serious illnesses such as cancer, stroke or heart disease/failure. In the most serious cases, an internal investigation will be triggered under the ‘NHS Duty of Candour’ procedure. Under this procedure the family/patient must be informed of the event and a full investigation into the facts completed by a review panel. This may include interview with the doctors involved and discussion with the patient or patient’s family.