SWLP is now able to carry out its first tests using mass spectrometry. Mass spectrometry is an analytical technique that accurately measures the mass of different molecules within a sample. It works by vapourising the molecules in a sample, which are then bombarded by nitrogen gas in an electric field, converting the vapours into ions. Any of the vapour that doesn’t ionise goes to waste, which significantly reduces any interference in the results. The sample then enters into the mass spectrometer and is then fragmented and fragmented again to generate a unique fingerprint for each compound.
SWLP has begun testing for steroids on the Waters Xevo TQ-S mass spectrometer, which is among the most sensitive available. The machine can test up to 960 samples in a single run, and can test for a number of different steroids using just one 100µl sample. More assay types are planned for the mass spectrometer in the near future.
There are a number of benefits of using mass spectrometry. Unlike other types of assay, there is no cross-reactivity, resulting in less interference and a true result. Very small samples can be used to test for multiple compounds, which means only one sample needs to be taken from the patient and results are available quickly. In some cases, blood can be taken at clinic and the result can be available the next day when the clinical report is being written.
Mass spectrometry also offers significant cost savings compared to conventional assays. Take as an example testing for steroids. Previously a separate test had to be carried out using a specific kit for each steroid. The multiplexing capability of mass spectrometry now requires a single reagent system.
Tony Dedman, who is in charge of mass spectrometry at SWLP, says, “Mass spectrometry is the future of pathology. It is perfect for large simultaneous screens and you can always be confident that the results you get are true results.”