Frequency of Cystic Fibrosis in Children with Recurrent Respiratory Infections by Sweat Chloride Testing: A Hospital-Based Cross-sectional Study

  • Nahdia Zaman Holy family hospital
  • Anam Zafar
  • Maryam Amjad
  • Shahzadi Sumbal Ghazi
  • Uzma Abid
  • Muhammad Haroon Hamid
Keywords: Cystic fibrosis, sweat chloride test, screening, respiratory tract infections.


Objective: This study was designed to find out the frequency of cystic fibrosis in children with recurrent respiratory infections by performing a sweat chloride test.
Material and Methods: This cross-sectional study was carried out from 1st September 2015 to 28th February 2016 in the department of Pediatric Medicine at the Children’s Hospital and the Institute of Child Health, Lahore after ethical approval. A total of 300 cases of recurrent respiratory tract infections were included. The sweat chloride test was done by using pilocarpine-induced iontophoresis and measuring chloride levels on the forearm or thigh by sweat analyzer at the time of induction. Cystic fibrosis was labeled if sweat chloride level ranges above 60 mEq/L. Data was collected on Performa and SPSS version 23 was used to analyze the data.
Results: Mean age of patients was 6.24 ± 2.7 years with 52.7% males and 47.3% females. Most patients (86.3%) have more than 5 episodes of respiratory infection in a year. Cystic fibrosis was diagnosed in 19 (6.3%) patients. There was no relationship between the frequency of respiratory infections in a year and cystic fibrosis (p-value 0.78).
Conclusion: This hospital-based study showed quite a high incidence of cystic fibrosis in our population. So facilities including neonatal screening along with sweat chloride testing and genetic analysis should be increased.


1. Basher S, Fatima S, Lodhi M A, Asif N, Hafeez A, Ayub A, et al. Pattern of cystic fibrosis based on sweat chloride test in children. Pakistan journal of pathology2017; Vol. 28(2): 85-91.
2. Aziz DA, Billoo AG, Qureshi A, Khalid M, Kirmani S, et al. Clinical and laboratory profile of children with Cystic Fibrosis: Experience of a tertiary care center in Pakistan. Pak J Med Sci, 2017. 33(3): p. 554-559. DOI: 10.12669/pjms.333.12188.
3. Lui JK, Kilch J, Fridlyand S, Dheyab A, Kotkowski CB. Non-Classic Cystic Fibrosis: The Value in Family History. Am J Med, 2017. 130(8): p. e333-e334.
4. Boeck K D, Vermeulen F, Dupont L, et al. The diagnosis of cystic fibrosis. Presse Med. 2017 Jun: 46(6pt2):e97-e108. DOI:10.1016/j.lpm.2017.04.010.
5. Farrell PM, Beryl J, Terry BW, et al. Guidelines for diagnosis of cystic fibrosis in newborns through older adults: Cystic Fibrosis Foundation consenus report. J Pediatr, 2008.153(2):p.S4-S14.
6. Celestino-Soper PBS, Simpson E, et al. Intragenic CFTR Duplication and 5T/12TG Variant in a Patient with Non-Classic Cystic Fibrosis. Sci Rep, 2016. 6: p. 38776.
7. Castaldo A, Cimbalo C, Castalo RJ, D'Artonio M, Scorza M, et al. Cystic fibrosis-screening positive inconclusive diagnosis: Newborn screening and long term follow up permits to early identify patients with CFTR related disorders. Diagnostics (Basel).2020 Aug: 10(8):570. DOI: 10.3390/diagnostics10080570.
8. Shah U, Frossard P, Moatter T. Cystic fibrosis: defining a disease under-diagnosed in Pakistan. Trop Med & Int Health, 2009. 14(5): p. 542-5.
9. Gonzalo-Ruiz J, Mas R, de Haro C, Cabruja E, Camero R,et al. Early determination of cystic fibrosis by electrochemical chloride quantification in sweat. Biosens Bioelectron,2008:24(6):p 1788-91.
10. Davis PB, Schluchter, Konstan MW. Relation of sweat chloride concentration to severity of lung disease in cystic fibrosis. Pediatr Pulmonol, 2004:38(3):p 204-209.
11. Al-Mendalawi MD. The use of sweat chloride test for screening cystic fibrosis among malnourished children suffering from frequent respiratory infections. Saudi Med J, 2010. 31(10): p. 1187; author reply 1187-8.
12. Singh M, Rebordosa C, Bernholz J, Sharma N. Epidemiology and genetics of cystic fibrosis in Asia: In preparation for the next-generation treatments. Respirology, 2015. 20(8): p. 1172-81.
13. VanDevanter DRP, Kahle JS, O'Sullivan AK, Sikirica S, Hodgkins PS et al., Cystic fibrosis in young children: A review of disease manifestation, progression, and response to early treatment. J Cyst Fibros, 2016. 15(2): p. 147-57. DOI:10.1016/j.jcf.2015.09.008.
14. Konstan MW, Mckone EF, Moss RB, Marigowda G, Trian S, et al. Assessment of safety and efficacy of long-term treatment with combination lumacaftor and ivacaftor therapy in patients with cystic fibrosis homozygous for the F508del-CFTR mutation (PROGRESS): a phase 3, extension study. The Lancet Respir Med, 2017. 5(2): p. 107-118.
15. Al-Abadi, B., et al., Cystic Fibrosis Gene Mutation Frequency Among a Group of Suspected Children in King Hussein Medical Center. Med Arch, 2019. 73(2): p. 118-120.
16. Connett, G.J., Lumacaftor-ivacaftor in the treatment of cystic fibrosis: design, development and place in therapy. Drug Des Devel Ther, 2019. 13: p. 2405-2412.
17. Shakoor, S., F. Mir, and R. Hasan, Common alternative diagnoses among a pediatric hospital-based cohort evaluated for tuberculosis in Karachi, Pakistan: The need for facilitated referral in tuberculosis clinics. Int J Mycobacteriol, 2019. 8(1): p. 42-47.
18. Ratte, M.T., et al., Survey of current treatment practices for venous thromboembolism in patients with cystic fibrosis. Pediatr Pulmonol, 2019.
19. Mona M. El-Falaki, Walaa A. Shahin, et al. Profile of cystic fibrosis in a single referral center in Egypt. J Adv Res. 2014 Sep; 5(5): 563–568. DOI: 10.1016/J.JARE.2013.07.005.
20. Caimmi D, Chiron R, Tremblay F, et al. Cystic fibrosis and antibiotic hypersensitivity: present knowledge and practical approach. Journal of Biological Regulators and Homeostatic Agents. 2015:29(2 Suppl 1):29-37.
21. Rafeeq MM, Aly H, Murad S. Cystic fibrosis: current therapeutic targets and future approaches. J Transl Med, 2017. 15(1): p.84. DOI: 10.1186/s12967-017-1193-9.
22. Jamal, M., et al., Treating Genetic Disorders Using State-Of-The-Art Technology. Curr Issues Mol Biol, 2018. 26: p. 33-46
23. Mishra A, Greaves R, Massie J. The Relevance of Sweat Testing for the Diagnosis of Cystic Fibrosis in the Genomic Era. Clin Biochem Rev. 2005 Nov; 26(4): 135–153
24. Leung DH, Heltshe SL, Borowitz D, et al. Effects of Diagnosis by Newborn Screening for Cystic fibrosis on weight and length in the first year of life. JAMA Pediatr. 2017; 171(6):546-554. DOI: 10.1001/jamapediatrics.2017.0206.
25. Ooi C Y, Castellani C, Keenan K, Avolio J, et al. Inconclusive diagnosis of cystic fibrosis after newborn screening. Pediatrics. 2015; 135(6):1377-85. DOI: 10.1542/peds.2014-2081.
26. Mattar AC, Leone C, Rodrigues JC, et al. Sweat chloride: An accurate diagnostic test for cystic fibrosis. J Cyst Fibros. 2014:13(5):528-33. DOI: 10.1016/j.jcf.2014.01.002.
How to Cite
Zaman N, Zafar A, Amjad M, Ghazi S, Abid U, Hamid M. Frequency of Cystic Fibrosis in Children with Recurrent Respiratory Infections by Sweat Chloride Testing: A Hospital-Based Cross-sectional Study. JRMC [Internet]. 30Dec.2020 [cited 1Oct.2022];24(4):302-5. Available from: