title: Measurement of urinary N tau-methylhistamine excretion: correlation of a newly developed radioimmunoassay (RIA) with gas chromatography mass spectrometry (GCMS).
abstract: A newly developed radioimmunoassay (RIA, Y) for the determination of urinary N tau-methylhistamine concentrations was correlated with gas chromatography mass spectrometry (GCMS, X). In 34 urine samples, with histamine and N tau-methylhistamine levels within our reference values, the correlation was: Y = 1.47X -0.245 mumol/l (r = 0.92; p-slope less than or equal to 0.0001). In 14 pathological urine samples, derived from patients with mastocytosis and having upper reference values, the correlation was: Y = 1.75X - 1.02 mumol/l (r = 0.93; p-slope less than or equal to 0.001). In spite of the greater specificity of the monoclonal antibody for N tau-methylhistamine compared with that of histamine, relatively high urinary histamine concentrations gave a false positive influence on the RIA results, which was 100% when the histamine/N tau-methylhistamine ratio was about 19. Clear cases of mastocytosis can be diagnosed, using the RIA-kit, but for a more precise N tau-methylhistamine value GCMS analyses will remain necessary.
authors.affiliation: ABL Analytical Biochemical Laboratory, Assen, The Netherlands.
authors.forename: E
authors.initials: E
authors.lastname: Oosting
authors.forename: J J
authors.initials: JJ
authors.lastname: Keyzer
mesh_terms: D005189:False Positive Reactions; D008401:Gas Chromatography-Mass Spectrometry / Q000706:statistics & numerical data; D006801:Humans; D008415:Mastocytosis / Q000652:urine*; D008761:Methylhistamines / Q000652:urine*; D011863:Radioimmunoassay / Q000706:statistics & numerical data; D012016:Reference Values
chemical_list: D008761:Methylhistamines; C031205:3-methylhistamine