1. Díez, M, Teulé, A, Salazar, R. Gastroenteropancreatic neuroendocrine tumors: diagnosis and treatment. Ann Gastroenterol 2013; 26: 29–36.
Google Scholar | Medline2. Vinik, AI, Woltering, EA, Warner, RRP, et al. NANETS consensus guidelines for the diagnosis of neuroendocrine tumor. Pancreas 2010; 39: 713–734.
Google Scholar | Crossref | Medline | ISI3. Aluri, V, Dillon, JS. Biochemical testing in neuroendocrine tumors. Endocrinol Metab Clin N Am 2017; 46: 669–677.
Google Scholar | Crossref | Medline4. Eriksson B, Kloppel G, Krenning E, et al. Consensus guidelines for the management of patients with digestive neuroendocrine tumors – well differentiated jejunal-ileal tumor/carcinoma. Neuroendocrinology 2007; 87: 8–19.
Google Scholar5. Ramage, JK, Ahmed, A, Ardill, J, et al. Guidelines for the management of gastroenteropancreatic neuroendocrine (including carcinoid) tumours (NETs). Gut 2012; 61: 6–32.
Google Scholar | Crossref | Medline | ISI6. Lips, CJ, Lentjes, EG, Hoppener, JW. The spectrum of carcinoid tumours and carcinoid syndromes. Ann Clin Biochem 2003; 40: 612–627.
Google Scholar | SAGE Journals | ISI7. Niederle, B, Pape, UF, Costa, F, et al. ENETS consensus guidelines update for neuroendocrine neoplasms of the jejunum and ileum. Neuroendocrinology 2016; 103: 125–138.
Google Scholar | Crossref | Medline8. Adaway, JE, Dobson, R, Walsh, J, et al. Serum and plasma 5-hydroxyindoleacetic acid as an alternative to 24-h urine 5-hydroxyindoleacetic acid measurement. Ann Clin Biochem 2016; 53: 554–560.
Google Scholar | SAGE Journals | ISI9. Meijer, WG, Kema, IP, Volmer, M, et al. Discriminating capacity of indole markers in the diagnosis of carcinoid tumors. Clin Chem 2000; 46: 1588–1596.
Google Scholar | Crossref | Medline10. Carling, RS, Degg, TJ, Allen, KR, et al. Evaluation of whole blood serotonin and plasma and urine 5-hydroxyindole acetic acid in diagnosis of carcinoid disease. Ann Clin Biochem 2002; 39: 577–582.
Google Scholar | SAGE Journals | ISI11. Clarke, W, Molinaro, RJ, Bachmann, LM, et al. Liquid chromatography-mass spectrometry methods; approved guideline. Pittsburgh: Clinical & Laboratory Standards Institute, 2014: p.34.
Google Scholar12. European Medicines Agency Guideline on bioanalytical method validation, www.ema.europa.eu/contact (2011, accessed 8 January 2019).
Google Scholar13. US Department of Health and Human Services . Bioanalytical method validation: guidance for industry, https://www.fda.gov/files/drugs/published/Bioanalytical-Method-Validation-Guidance-for-Industry.pdf (2018, accessed 22 January 2019).
Google Scholar14. O’Toole, D, Grossman, A, Gross, D, et al. ENETS consensus guidelines for the standards of care in neuroendocrine tumors: biochemical markers. Neuroendocrinology 2009; 90: 194–202.
Google Scholar | Crossref | Medline | ISI15. NHS. The NHS constitution for England, www.gov.uk/government/publications/the-nhs-constitution-for-england/the-nhs-constitution-for-england (2021, accessed 26 Febuary 2021).
Google Scholar16. Perry, H, Keevil, B. Online extraction of 5-hydroxyindole acetic acid from urine for analysis by liquid chromatography-tandem mass spectrometry. Ann Clin Biochem 2008; 45: 149–152.
Google Scholar | SAGE Journals | ISI17. Clark, ZD, Cutler, JM, Frank, EL. Practical LC-MS/MS method for 5-hydroxyindoleacetic acid in urine. J Appl Lab Med 2017; 1: 387–399.
Google Scholar | Crossref | Medline18. Miller, AG, Brown, H, Degg, T, et al. Measurement of plasma 5-hydroxyindole acetic acid by liquid chromatography tandem mass spectrometry – comparison with HPLC methodology. J Chromatogr B Anal Technol Biomed Life Sci 2010; 878: 695–699.
Google Scholar | Crossref | Medline | ISI19. de Jong, WHA, Graham, KS, de Vries, EGE, et al. Urinary 5-HIAA measurement using automated on-line solid-phase extraction-high-performance liquid chromatography-tandem mass spectrometry. J Chromatogr B Anal Technol Biomed Life Sci 2008; 868: 28–33.
Google Scholar | Crossref | Medline20. Moriarty, M, Lee, A, O’Connell, B, et al. Development of an LC-MS/MS method for the analysis of serotonin and related compounds in urine and the identification of a potential biomarker for attention deficit hyperactivity/hyperkinetic disorder. Anal Bioanal Chem 2011; 401: 2481–2493.
Google Scholar | Crossref | Medline21. Deacon, AC. The measurement of 5-hydroxyindoleacetic acid in urine. Ann Clin Biochem 1994; 31: 215–232.
Google Scholar | SAGE Journals | ISI22. Waters . CORTECS Columns, www.waters.com/waters/en_US/Solid-Core-Particle-Columns/nav.htm?cid=134740934&xcid=ext549&gclid=EAIaIQobChMI7rLnso-s3wIVms13Ch1fywKqEAAYASAAEgLg8PD_BwE&locale=en_US (accessed 28 December 2020).
Google Scholar23. Taylor, PJ. Matrix effects: the Achilles heel of quantitative high-performance liquid chromatography-electrospray-tandem mass spectrometry. Clin Biochem 2005; 38: 328–334.
Google Scholar | Crossref | Medline | ISI24. Tang, L, Kebarle, P. Dependence of ion intensity in electrospray mass spectrometry on the concentration of the analytes in the electrosprayed solution. Anal Chem 1993; 65: 3654–3668.
Google Scholar | Crossref | ISI25. Davison, AS, Milan, AM, Dutton, JJ. Potential problems with using deuterated internal standards for liquid chromatography-tandem mass spectrometry. Ann Clin Biochem 2013; 50: 274.
Google Scholar | SAGE Journals | ISI26. BIPM, IEC, IFCC, ILAC, ISO, IUPAC I and O International vocabulary of metrology – basic and general concepts and associated terms (VIM), JCGM. Geneva: Int Organ Stand, 2012, p.200.
Google Scholar