The IMS Laboratory is based within the Heart Science Centre at Harefield Hospital. The primary function of the department is to perform therapeutic drug monitoring and clinical diagnostics by mass spectrometry

The department commenced a development program for novel Mass spectrometry methods for Cyclosporin and Tacrolimus in 1997. Harefield was the first laboratory in the UK to introduced routine 7 day week mass spectrometry services for immunosuppressives in 1999.

In June 2001 the department began the National Monitoring Service for Sirolimus. This is provided by this NHS Trust as a service to the whole of the UK and Eire.

The department continues to research and develop new methods and monitoring strategies.