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Sweat chloride assay by inductively coupled plasma mass spectrometry: a confirmation test for cystic fibrosis diagnosis.
Marvelli, Antonella; Campi, Beatrice; Mergni, Gianfranco; Di Cicco, Maria Elisa; Turini, Paola; Scardina, Paolo; Zucchi, Riccardo; Pifferi, Massimo; Taccetti, Giovanni; Paolicchi, Aldo; la Marca, Giancarlo; Saba, Alessandro.
Afiliação
  • Marvelli A; Department of Surgical, Medical and Molecular Pathology and Critical Care Medicine, University of Pisa, Pisa, Italy.
  • Campi B; C.N.R. Institute of Clinical Physiology, Pisa, Italy.
  • Mergni G; Cystic Fibrosis Laboratory, Meyer Children's University Hospital, Florence, Italy.
  • Di Cicco ME; Pediatric Division, Department of Obstetrics, Gynecology and Pediatrics, St. Chiara University Hospital, Pisa, Italy.
  • Turini P; Laboratory of Clinical Pathology, Department of Laboratory Medicine, St. Chiara University Hospital, Pisa, Italy.
  • Scardina P; Agilent Technologies Italia S.p.A. Cernusco sul Naviglio, Milan, Italy.
  • Zucchi R; Department of Surgical, Medical and Molecular Pathology and Critical Care Medicine, University of Pisa, Pisa, Italy.
  • Pifferi M; Pediatric Division, Department of Obstetrics, Gynecology and Pediatrics, St. Chiara University Hospital, Pisa, Italy.
  • Taccetti G; Cystic Fibrosis Laboratory, Meyer Children's University Hospital, Florence, Italy.
  • Paolicchi A; Laboratory of Clinical Pathology, Department of Laboratory Medicine, St. Chiara University Hospital, Pisa, Italy.
  • la Marca G; Department of Translational Research and of New Surgical and Medical Technologies, University of Pisa, Pisa, Italy.
  • Saba A; Department of Experimental and Clinical Biomedical Sciences, University of Florence, Florence, Italy.
Anal Bioanal Chem ; 412(25): 6909-6916, 2020 Oct.
Article em En | MEDLINE | ID: mdl-32691087
The current guidelines for sweat chloride analysis identify the procedures for sweat collection, but not for chloride assay, which is usually performed by methods originally not aiming at the low concentrations of chloride found in sweat. To overcome this limitation, we set up, characterized, and adopted an original inductively coupled plasma mass spectrometry (ICP-MS) method for sweat chloride determination, which was designed for its easy use in a clinical laboratory. The method was linear in the range 8.5E-3 to 272.0E-3 mM, precision exhibited a relative standard deviation < 6%, and accuracy was in the range 99.7-103.8%. Limit of blank, limit of detection, and limit of quantitation were 2.1 mM, 3.2 mM, and 7.0 mM, respectively, which correspond to real concentrations injected into the mass spectrometer of 3.9E-3 mM for LOD and 8.5E-3 mM for LOQ. At first, the method was tested on 50 healthy volunteers who exhibited a mean chloride concentration of 15.7 mM (25-75th percentile 10.1-19.3 mM, range 2.8-37.4 mM); then, it was used to investigate two patients with suspected cystic fibrosis, who exhibited sweat chloride values of 65.6 mM and 81.2 mM, respectively. Moreover, the method was cross-validated by assaying 50 samples with chloride concentration values in the range 10-131 mM, by both ICP-MS and coulometric titration, which is the technology officially used in Tuscany for cystic fibrosis newborn screening. The reference analytical performances and the relatively low cost of ICP-MS, accompanied by the advantageous cost of a single sweat chloride assay, make this technology the best candidate to provide a top reference method for the quantification of chloride in sweat. The method that we propose was optimized and validated for sweat samples ≥ 75 mg, which is the minimum amount requested by the international protocols. However, the method sensitivity and, in addition, the possibility to reduce the sample dilution factor, make possible the quantification of chloride even in samples weighting < 75 mg that are discarded according to the current guidelines. Graphical abstract.
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Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Espectrometria de Massas / Suor / Cloretos / Fibrose Cística Tipo de estudo: Diagnostic_studies / Guideline / Observational_studies / Prognostic_studies Limite: Adult / Humans / Middle aged Idioma: En Ano de publicação: 2020 Tipo de documento: Article

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Espectrometria de Massas / Suor / Cloretos / Fibrose Cística Tipo de estudo: Diagnostic_studies / Guideline / Observational_studies / Prognostic_studies Limite: Adult / Humans / Middle aged Idioma: En Ano de publicação: 2020 Tipo de documento: Article