title: A single fasting plasma 5-HIAA value correlates with 24-hour urinary 5-HIAA values and other biomarkers in midgut neuroendocrine tumors (NETs).
abstract: OBJECTIVE
  5-Hydroxyindoleacetic acid (5-HIAA) is used for the evaluation of neuroendocrine tumors (NETs) but currently requires a 24-hour urine collection.
  
  
  METHODS
  We developed a gas chromatography mass spectroscopy-based plasma 5-HIAA assay. We compared 24-hour urine 5-HIAA values against plasma 5-HIAA values in 115 mixed-variety patients with NETs and in a subset of 72 patients with only small bowel NETs. We also compared the information gained from urinary and plasma 5-HIAA values with other biomarkers of midgut NET activity to determine the plasma assay's clinical implications.
  
  
  RESULTS
  In a group of 115 patients with all types of NETS, in a subset of patients with midgut NET and in a subgroup of midgut NETS with liver metastasis, the correlation between the urine and fasting plasma 5-HIAA values were statistically significant (P ≤ 0.0001). Comparison of the proportion of normal or abnormal urinary and plasma 5-HIAA values to the proportion of chromogranin, serotonin, neurokinin, or pancreastatin values that were in the normal or abnormal range yielded essentially identical information.
  
  
  CONCLUSIONS
  Plasma fasting 5-HIAA values are proportional to urinary 5-HIAA values and yielded identical clinical correlation with other biomarkers.
authors.affiliation: Inter Science Institute, Inglewood, CA, USA.
authors.forename: Maria R
authors.initials: MR
authors.lastname: Tellez
authors.forename: Gregg
authors.initials: G
authors.lastname: Mamikunian
authors.forename: Thomas M
authors.initials: TM
authors.lastname: O'Dorisio
authors.forename: Aaron I
authors.initials: AI
authors.lastname: Vinik
authors.forename: Eugene A
authors.initials: EA
authors.lastname: Woltering
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000032:analysis* / Q000097:blood / Q000652:urine; D053379:Chromogranin A / Q000032:analysis; D018450:Disease Progression; D005215:Fasting / Q000097:blood; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D006801:Humans; D006897:Hydroxyindoleacetic Acid / Q000032:analysis* / Q000097:blood / Q000652:urine; D007414:Intestinal Neoplasms / Q000097:blood / Q000473:pathology* / Q000652:urine; D008113:Liver Neoplasms / Q000097:blood / Q000556:secondary / Q000652:urine; D008297:Male; D008875:Middle Aged; D018358:Neuroendocrine Tumors / Q000097:blood / Q000473:pathology* / Q000652:urine; D015288:Neurokinin A / Q000032:analysis; D010187:Pancreatic Hormones / Q000032:analysis; D011379:Prognosis; D012016:Reference Values; D012680:Sensitivity and Specificity; D012701:Serotonin / Q000032:analysis
chemical_list: D015415:Biomarkers; D053379:Chromogranin A; D010187:Pancreatic Hormones; C050836:pancreastatin; D012701:Serotonin; D006897:Hydroxyindoleacetic Acid; D015288:Neurokinin A