title: Assessment of Correlation between Sweat Chloride Levels and Clinical Features of Cystic Fibrosis Patients.
abstract: BACKGROUND
  Cystic Fibrosis (CF) is an autosomal recessive disorder and the incidence of this disease is undermined in Northern India. The distinguishable salty character of the sweat belonging to individuals suffering from CF makes sweat chloride estimation essential for diagnosis of CF disease.
  
  
  OBJECTIVE
  The aim of this prospective study was to elucidate the relationship of sweat chloride levels with clinical features and pattern of CF.
  
  
  METHODS
  A total of 182 patients, with clinical features of CF were included in this study for quantitative measurement of sweat chloride. Sweat stimulation and collection involved pilocarpine iontophoresis based on the Gibson and Cooks methodology. The quantitative estimation of chloride was done by Schales and Schales method with some modifications. Cystic Fibrosis Trans Membrane Conductance Regulator (CFTR) mutation status was recorded in case of patients with borderline sweat chloride levels to correlate the results and for follow-up.
  
  
  RESULTS
  Out of 182 patients having clinical features consistent with CF, borderline and elevated sweat chloride levels were present in 9 (5%) and 41 (22.5%) subjects respectively. Elevated sweat chloride levels were significantly associated with wheeze, Failure To Thrive (FTT), history of CF in Siblings, product of Consanguineous Marriage (CM), digital clubbing and steatorrhoea on univariate analysis. On multivariate analysis only wheeze, FTT and steatorrhoea were found to be significantly associated with elevated sweat chloride levels (p<0.05). Among the nine borderline cases six cases were positive for at least two CFTR mutations and rest of the three cases were not having any mutation in CFTR gene.
  
  
  CONCLUSIONS
  The diagnosis is often delayed and the disease is advanced in most patients at the time of diagnosis. Sweat testing is a gold standard for diagnosis of CF patients as genetic mutation profile being heterozygous and unlikely to become diagnostic test.
authors.affiliation: Junior Research Fellow, Department of Clinical Biochemistry, Sher-I-Kashmir Institute of Medical Sciences , Soura, Srinagar, Jammu and Kashmir, India .
authors.forename: Manzoor A
authors.initials: MA
authors.lastname: Raina
authors.affiliation: Senior Resident, Department of Clinical Biochemistry, Sher-I-Kashmir Institute of Medical Sciences , Soura, Srinagar, Jammu and Kashmir, India .
authors.forename: Mosin S
authors.initials: MS
authors.lastname: Khan
authors.affiliation: PhD Scholar, Department of Clinical Biochemistry, Sher-I-Kashmir Institute of Medical Sciences , Soura, Srinagar, Jammu and Kashmir, India .
authors.forename: Showkat A
authors.initials: SA
authors.lastname: Malik
authors.affiliation: Senior Resident, Department of Internal Medicine, Sher-I-Kashmir Institute of Medical Sciences , Soura, Srinagar, Jammu and Kashmir, India .
authors.forename: Ab Hameed
authors.initials: AH
authors.lastname: Raina
authors.affiliation: Junior Research Fellow, Department of Clinical Biochemistry, Sher-I-Kashmir Institute of Medical Sciences , Soura, Srinagar, Jammu and Kashmir, India .
authors.forename: Mudassir J
authors.initials: MJ
authors.lastname: Makhdoomi
authors.affiliation: Assistant Professor, Department of Paediatrics, Sher-I-Kashmir Institute of Medical Sciences , Soura, Srinagar, Jamu and Kashmir, India .
authors.forename: Javed I
authors.initials: JI
authors.lastname: Bhat
authors.affiliation: Professor and Head, Department of Clinical Biochemistry, Sher-I-Kashmir Institute of Medical Sciences , Soura, Srinagar, Jammu and Kashmir, India .
authors.forename: Syed
authors.initials: S
authors.lastname: Mudassar
keywords: Bronchiectasis; Kashmir; Pilocarpine iontophoresis; Steatorrhoea; Sweat testing; Wheeze