title: A serum and platelet-rich plasma serotonin assay using liquid chromatography tandem mass spectrometry for monitoring of neuroendocrine tumor patients.
abstract: BACKGROUND
  Serotonin is used for the diagnosis and follow-up of neuroendocrine tumors (NET). We describe the analytical and clinical validation of a liquid chromatography tandem mass spectrometry (LC-MS/MS) based serotonin assay for serum and platelet-rich plasma (PRP).
  
  
  METHODS
  An LC-MS/MS based method for serum and PRP serotonin was validated by determination of assay imprecision, carry-over, linearity, interference, recovery, sample stability and a matrix/method comparison of serum and PRP serotonin was made with whole blood serotonin. Furthermore, upper limits of normal were determined and serotonin concentrations of healthy individuals, 14 NET patients without evidence of disease and 51 NET patients with evidence of disease were compared.
  
  
  RESULTS
  For serum and PRP fractions, total assay imprecision was <5%. All correlation coefficients were 0.98 and the serum and platelet-rich serotonin upper limit of normal were 5.5nmol/109platelet and 5.1nmol/109platelet, respectively. NET patients with confirmed evidence of disease had significantly higher serum and PRP serotonin levels when compared to NET patients without evidence of disease and healthy volunteers.
  
  
  CONCLUSIONS
  LC-MS/MS based serum and PRP serotonin assays were developed with suitable analytical characteristics. Furthermore, serum and PRP serotonin was found to be useful for monitoring NET patients.
authors.affiliation: Laboratory of Clinical Chemistry and Hematology, The Netherlands Cancer Institute, The Netherlands.
authors.forename: Catharina M
authors.initials: CM
authors.lastname: Korse
authors.affiliation: Laboratory of Clinical Chemistry and Hematology, The Netherlands Cancer Institute, The Netherlands.
authors.forename: Johanna C G M
authors.initials: JCGM
authors.lastname: Buning-Kager
authors.affiliation: Laboratory of Clinical Chemistry and Hematology, The Netherlands Cancer Institute, The Netherlands.
authors.forename: Theodora C
authors.initials: TC
authors.lastname: Linders
authors.affiliation: Endocrine Laboratory, Department of Clinical Chemistry, VU University Medical Center, Amsterdam, The Netherlands.
authors.forename: Annemieke C
authors.initials: AC
authors.lastname: Heijboer
authors.affiliation: Laboratory of Clinical Chemistry and Hematology, The Netherlands Cancer Institute, The Netherlands.
authors.forename: Daan
authors.initials: D
authors.lastname: van den Broek
authors.affiliation: Medical Oncology, The Netherlands Cancer Institute, The Netherlands.
authors.forename: Margot E T
authors.initials: MET
authors.lastname: Tesselaar
authors.affiliation: Laboratory of Clinical Chemistry and Hematology, The Netherlands Cancer Institute, The Netherlands.
authors.forename: Olaf
authors.initials: O
authors.lastname: van Tellingen
authors.affiliation: Laboratory of Clinical Chemistry and Hematology, The Netherlands Cancer Institute, The Netherlands. Electronic address: h.v.rossum@nki.nl.
authors.forename: Huub H
authors.initials: HH
authors.lastname: van Rossum
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001774:Blood Chemical Analysis / Q000379:methods*; D002853:Chromatography, Liquid; D005260:Female; D006801:Humans; D057230:Limit of Detection; D008297:Male; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000097:blood*; D053657:Platelet-Rich Plasma / Q000737:chemistry*; D012701:Serotonin / Q000097:blood*; D044967:Serum / Q000737:chemistry*; D053719:Tandem Mass Spectrometry; D055815:Young Adult
chemical_list: D012701:Serotonin
keywords: LC-MS; LC-MS/MS; NET; Neuroendocrine tumor; Serotonin