Joanne E Adaway1, Mirko Peitzsch2, Brian G Keevil3. 1. Department of Clinical Biochemistry, University Hospital South Manchester NHS Foundation Trust, Manchester, UK Manchester Academic Health Science Centre, University Hospital South Manchester, The University of Manchester, Manchester, UK Jo.adaway@uhsm.nhs.uk. 2. Institute of Clinical Chemistry and Laboratory Medicine, University Hospital Carl Gustav Carus, Medical Faculty Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany. 3. Department of Clinical Biochemistry, University Hospital South Manchester NHS Foundation Trust, Manchester, UK Manchester Academic Health Science Centre, University Hospital South Manchester, The University of Manchester, Manchester, UK.
Abstract
BACKGROUND: Measurement of plasma metanephrine, normetanephrine and 3-methoxytyramine is useful in the diagnosis of phaeochromocytomas, but many assays require a large volume of plasma due to poor assay sensitivity, and often require lengthy sample preparation. Our aim was to develop a method for measurement of plasma metanephrines using a small sample volume with minimal hands-on preparation. METHODS: Samples were deproteinised using 10 K spin filters prior to online solid phase extraction using a Waters Acquity UPLC Online SPE Manager (Waters, Manchester, UK) coupled to a Waters Xevo TQ-S mass spectrometer (Waters, Manchester, UK). The assay was validated and results compared to a previously published method. RESULTS: We achieved a limit of quantification of 37.5 pmol/L for metanephrine and 3-methoxytyramine and 75 pmol/L for normetanephrine using only 150 µL of sample. The assay was linear up to 30,000 pmol/L for all analytes and in a method comparison study results showed good agreement with a previously published LC-MS/MS assay. CONCLUSIONS: We have developed a simple method for measurement of plasma metanephrine, normetanephrine and 3-methoxytyramine using only 150 µL of sample. There is minimal hands-on sample preparation required and the assay is suitable for routine use in a clinical laboratory.
BACKGROUND: Measurement of plasma metanephrine, normetanephrine and 3-methoxytyramine is useful in the diagnosis of phaeochromocytomas, but many assays require a large volume of plasma due to poor assay sensitivity, and often require lengthy sample preparation. Our aim was to develop a method for measurement of plasma metanephrines using a small sample volume with minimal hands-on preparation. METHODS: Samples were deproteinised using 10 K spin filters prior to online solid phase extraction using a Waters Acquity UPLC Online SPE Manager (Waters, Manchester, UK) coupled to a Waters Xevo TQ-S mass spectrometer (Waters, Manchester, UK). The assay was validated and results compared to a previously published method. RESULTS: We achieved a limit of quantification of 37.5 pmol/L for metanephrine and 3-methoxytyramine and 75 pmol/L for normetanephrine using only 150 µL of sample. The assay was linear up to 30,000 pmol/L for all analytes and in a method comparison study results showed good agreement with a previously published LC-MS/MS assay. CONCLUSIONS: We have developed a simple method for measurement of plasma metanephrine, normetanephrine and 3-methoxytyramine using only 150 µL of sample. There is minimal hands-on sample preparation required and the assay is suitable for routine use in a clinical laboratory.
Authors: Martijn van Faassen; Rainer Bischoff; Karin Eijkelenkamp; Wilhelmina H A de Jong; Claude P van der Ley; Ido P Kema Journal: Anal Chem Date: 2020-06-12 Impact factor: 6.986