Tests and methods

The process of arriving at a diagnosis much resembles a detective story. Its success relies heavily on good levels of open minded communication with your doctor, both ways, and engaging with their questions in order to find out about your medical history and your current problems. It helps if you can resist any temptations to speculate about your problem as this may distract you from concentrating on the communication and conversation with your doctor. This conversation alone often goes a long way in the process, especially in combination with a thorough medical examination.

A whole arsenal of methods and techniques are available and widely used to exclude and/or confirm some diagnoses. Taking a tissue sample for further examination (a biopsy) usually clarifies an initial tentative diagnosis. Many different microbiological methods and biochemical marker molecules in your blood or urine provide information about many conditions and their severity as well as giving information about the safety of exposing you to various diagnostic and other procedures.

In addition to these methods based on the chemical and biochemical behaviour of your body, many physical effects and techniques are also useful to gather information about the structure and/or function of your body. These physical techniques include ordinary X-ray radiographs and CT scans where a large number of  X-ray ‘pictures’ are taken in one series to obtain a three-dimensional image of parts of your body. Sometimes CT scanning is combined with positron emission tomography, PET scans. PET scans rely on signals emitted from very small amounts of radioactive materials and provide three-dimensional images.

A third physical method that yields three-dimensional images is magnetic resonance imaging, MRI. MRI relies on strong external magnetic fields and radiofrequency irradiation which is a very low energy irradiation and does not harm body tissues. All three imaging techniques have strengths and weaknesses which complement each other and thus will be used for different purposes. Another commonly used low-energy irradiation technique predominantly for imaging of soft tissues is based on ultrasound waves.