One of the rapidly growing concerns in medicine is the anxiety that a lot of drugs do not work for a large number of the patients for whom they are prescribed.

By Frances Griss

Finding the right drug for an individual can be a question of trial and error so the future of treatment is for personalised medicine based on each patient’s molecular biology and an approach that splits diseases into sub-types according to their treatment, not the symptoms.

Molecular diagnostics uses genetic markers or the proteins by which they express themselves to point clinicians towards an effective treatment first time. In addition the technique can be used to provide a firm diagnosis to differentiate between conditions exhibiting similar symptoms.

The chemistry behind molecular diagnostics relies on the ability to amplify a sample of DNA before it can be accurately identified and this is carried out using a polymerase chain reaction (PCR). Reactions require a repeated heating and cooling cycle in the presence of a primer, a short section of DNA which is complementary to the section you wish to amplify, and DNA polymerase.

Hardware for carrying out the tests is constantly evolving with plenty of competition to develop everything from large-scale platforms to tiny portable, battery-operated versions weighing less than 500g, although the latter is not really intended for clinical use. The potential of the approach is that it removes guesswork, allowing specific diagnosis of individual pathogens which leads to more targeted treatment.