Participants were informed from the outset that the study was investigating the feasibility of collecting urine samples and testing whether patients had taken all of their medications as prescribed. They were reassured that this information would remain entirely confidential and members of the care team would not be made aware of the results of the urine test. A 10 ml urine sample was collected in a standard plastic container immediately after informed consent had been obtained. Each sample was transferred from the clinic site to the laboratory at University Hospitals of Leicester at room temperature, via a post office next day delivery service. We have previously demonstrated that samples remain stable for 72 hours after collection.(19 )
All samples received by the laboratory were stored at -80°C and then batch analysed at the end of the study. LC-MS/MS was performed to detect all antihypertensive drug classes, using an Agilent Technologies 1200 series High Pressure Liquid Chromatograph interfaced with an Agilent Technologies 6410 Triple Quad Mass Spectrometer fitted with a Jetstream electrospray (ESI) source.(17 (link)) The test is a standard laboratory test that is accredited by United Kingdom Accreditation Service (UKAS). All samples were destroyed at the end of the study, after the analysis had been completed.
All samples received by the laboratory were stored at -80°C and then batch analysed at the end of the study. LC-MS/MS was performed to detect all antihypertensive drug classes, using an Agilent Technologies 1200 series High Pressure Liquid Chromatograph interfaced with an Agilent Technologies 6410 Triple Quad Mass Spectrometer fitted with a Jetstream electrospray (ESI) source.(17 (link)) The test is a standard laboratory test that is accredited by United Kingdom Accreditation Service (UKAS). All samples were destroyed at the end of the study, after the analysis had been completed.