Determination of 1-methylhistamine and 1-methylimidazoleacetic acid in human urine as a tool for the diagnosis of mastocytosis

The determination of the metabolites of histamine, 1-methylhistamine (MHIS) and 1-methylimidazoleacetic acid (MIIA), in human urine is a useful tool f or the diagnosis of mastocytosis. MHIS was extracted under basic conditions with chloroform and derivatized with trifluoroacetic acid anhydride, MIIA was derivatized with pentafluorobenzylbromide prior to extraction under bas ic conditions and the derivative was extracted with chloroform. The samples were assayed by gas chromatography-mass spectrometry. Normal concentration s of MHIS (2.01 mu mol l(-1)) and MIIA (21.3 mu mol l(-1)) in healthy volun teers' urine samples are clearly detectable with coefficients of variation of 7.0 and 8.9%. Pathological concentrations of 10.1 and 113 mu mol l(-1) f or MHIS and MIIA, respectively, are quantifiable with coefficients of varia tion of 6.6 and 4.8%. (C) 1999 Elsevier Science B.V. All rights reserved.