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Development and analytic validation of an electron ionization gas chromatography/mass spectrometry ( EI ‐ GC / MS ) method for the measurement of 3‐bromotyrosine in canine serum
Author(s) -
Sattasathuchana Panpicha,
Berghoff Nora,
Grützner Niels,
Thengchaisri Naris,
Rangachari Venkat R.,
Suchodolski Jan S.,
Steiner Jörg M.
Publication year - 2016
Publication title -
veterinary clinical pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.537
H-Index - 51
eISSN - 1939-165X
pISSN - 0275-6382
DOI - 10.1111/vcp.12373
Subject(s) - detection limit , chemistry , reproducibility , chromatography , mass spectrometry , biomarker , gas chromatography–mass spectrometry , gas chromatography , confidence interval , analytical chemistry (journal) , medicine , biochemistry
Background The activation of eosinophils causes the release of eosinophil peroxidase and subsequent production of 3‐bromotyrosine (3‐BrY), a stable byproduct. In people, 3‐BrY is used as a biomarker for eosinophil activation. The method for measuring 3‐BrY concentrations in biologic samples from dogs has not previously been described. Objectives The objective of this study was to develop and analytically validate an electron ionization gas chromatography/mass spectrometry ( EI ‐ GC / MS ) method for the measurement of 3‐BrY in canine serum samples. Methods Pooled canine serum samples were utilized to validate the assay. Serum samples from healthy control dogs ( n = 41) were used to evaluate 3‐BrY concentrations and establish a reference interval. Results The analytic validation revealed that the limit of blank and limit of detection were 0.33 and 0.63 μmol/L, respectively. The coefficients of variation for precision and reproducibility for 3‐BrY were < 13.9% and < 11.0%, respectively. The means ± SD of observed‐to‐expected ratios for linearity and accuracy were 109.6 ± 17.2% and 98.7 ± 11.3%, respectively. The reference interval was determined as ≤ 1.12 μmol/L (median [range]: ≤ 0.63 μmol/L [≤ 0.63–1.13]). Conclusions The EI ‐ GC / MS assay described here for the measurement of 3‐BrY in canine serum samples was precise, reproducible, linear, and accurate. Further studies are underway to determine the diagnostic utilities in canine patients with eosinophilic diseases.