title: Single-centre study of the diagnostic performance of plasma metanephrines with seated sampling for the diagnosis of phaeochromocytoma/paraganglioma.
abstract: Background Measurement of plasma metanephrines is regarded as one of the best screening tests for phaeochromocytoma/paraganglioma. Current guidelines recommend that samples are ideally collected in the supine position after 30 min rest and interpreted using supine reference ranges, in order to optimize the diagnostic performance of the test. Current practice in our centre is to collect samples for plasma metanephrines from seated patients. The aim of the study was to determine, if seated sampling for plasma metanephrines provides acceptable diagnostic performance in our centre. Methods Clinical and laboratory data of 113 patients, gathered over a four-year period 2010-2014, were reviewed. All had undergone preoperative plasma metanephrines measurement and had postoperative histopathology confirmation or exclusion of phaeochromocytoma/paraganglioma. Results Of 113 patients included in the study, 40 had a histological diagnosis of phaeochromocytoma/paraganglioma. The remaining 73 patients had an alternative adrenal pathology. The diagnostic sensitivity of normetanephrine or metanephrine above the upper limit of our in-house seated reference range was 93%. However, excluding three cases of paraganglioma determined clinically and biochemically to be non-functional raised the sensitivity to 100%. Diagnostic specificity was 90%. Applying published supine reference ranges made no difference to diagnostic sensitivity in this group of patients but decreased diagnostic specificity to 75%. Conclusions While these data are derived from a relatively small study population, they demonstrate acceptable diagnostic performance for seated plasma metanephrines as a screening test for phaeochromocytoma/paraganglioma. These data highlight a high diagnostic sensitivity for plasma metanephrines with seated sampling in our centre.
authors.affiliation: 1 Blood Sciences, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK.
authors.forename: Christopher
authors.initials: C
authors.lastname: Boot
authors.affiliation: 1 Blood Sciences, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK.
authors.forename: Barry
authors.initials: B
authors.lastname: Toole
authors.affiliation: 2 Department of Cellular Pathology, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK.
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Johnson
authors.affiliation: 3 Department of Endocrinology, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK.|4 School of Medicine, Newcastle University, Newcastle upon Tyne, UK.
authors.forename: Stephen
authors.initials: S
authors.lastname: Ball
authors.affiliation: 1 Blood Sciences, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK.
authors.forename: Dermot
authors.initials: D
authors.lastname: Neely
mesh_terms: D000293:Adolescent; D000310:Adrenal Gland Neoplasms / Q000097:blood / Q000175:diagnosis* / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000097:blood*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008676:Metanephrine / Q000097:blood*; D008875:Middle Aged; D010235:Paraganglioma / Q000097:blood / Q000175:diagnosis* / Q000473:pathology; D056888:Patient Positioning / Q000379:methods; D010673:Pheochromocytoma / Q000097:blood / Q000175:diagnosis* / Q000473:pathology; D011187:Posture; D017410:Practice Guidelines as Topic; D012016:Reference Values; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
chemical_list: D014408:Biomarkers, Tumor; D008676:Metanephrine
keywords: Metanephrine; normetanephrine; paraganglioma; phaeochromocytoma