Laboratory Diagnosis of Cystic Fibrosis

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Author: Vicky LeGrys, DA, MT(ASCP)
Reviewer: Rebecca J. Laudicina, PhD, MLS(ASCP)CM

This course discusses the clinical presentation of cystic fibrosis (CF) and how genetic mutations can lead to the manifestation of the disorder. Laboratory testing used in the diagnosis of CF is presented including the components of a quantitative sweat chloride test. Finally, current treatment options for the disease are discussed.

Continuing Education Credits


  • Describe the clinical presentation of cystic fibrosis (CF).
  • Describe how mutations in the CF gene lead to the clinical manifestations of the disorder.
  • Outline the laboratory diagnosis of CF to include newborn screening, the sweat test, and DNA testing.
  • Describe the components of a quantitative sweat chloride test to include reference ranges.
  • Compare screening sweat tests to confirmatory sweat tests.
  • Discuss the current treatment options for CF.

Course Outline

  • Introduction to Cystic Fibrosis
      • Course Introduction
  • The History of CF
      • History of CF and Diagnostic Testing
  • Pathophysiology of CF
      • Pathophysiology of CF
      • Mutations of Cystic Fibrosis Transmembrane Conductance Regulator (CFTR)
      • CF is due to a defect in a protein which functions as a(n):
  • Clinical Presentation
      • Overview of Clinical Characteristics
      • Pulmonary Disease
      • Pancreatic Disease
      • Sweat Gland Involvement
      • Gastrointestinal and Liver Disease
      • Reproductive System
      • Which of the following pathogens is associated with CF pulmonary disease?
      • Which of the following statements concerning the sweat of patients with CF is TRUE?
  • Laboratory Diagnosis of CF
      • Laboratory Diagnosis of CF
      • Newborn Screening (NBS) in the United States
      • DNA Testing
      • Why do patients with a positive newborn screening test for CF require confirmation of the diagnosis?
    • Sweat Testing
      • Sweat Testing
      • Sweat Stimulation
      • Sweat Collection
      • Collecting An Adequate Sweat Sample
      • Quantitative Sweat Analysis
      • Screening Tests for Sweat
      • Reference Intervals for Sweat Chloride
      • Reference Intervals for Sweat Conductivity
      • Quality Assurance for Sweat Testing
      • CF is the only disorder that will result in increased sweat chloride concentrations.
      • When performing sweat testing for CF diagnosis, how long is sweat stimulated by iontophoresis and how long is it collected?
  • Treatment
      • Treatment
      • Treating the Symptoms
      • Treating the Protein Defect
      • Gene Replacement
      • Which of the following statements are TRUE concerning medications that treat the protein defect in CF?
  • Summary
      • Summary
  • References
      • References

Additional Information

Level of instruction: Intermediate

Intended Audience: Medical laboratory scientists, medical technologists, and technicians. This course is also appropriate for medical laboratory science students and pathology residents.

Author information: Vicky LeGrys, DA, MT(ASCP) is a professor in the Division of Clinical Laboratory Science in the School of Medicine at the University of North Carolina Chapel Hill where she is responsible for the lecture and laboratory courses in Biochemistry, Clinical Chemistry, and Quality Assurance. She holds a Doctorate of Arts and a Master of Science in Medical Technology from Catholic University of America, Washington DC with a major in Clinical Chemistry.
Reviewer information: Rebecca J. Laudicina, PhD, MLS(ASCP)CM is Professor Emeritus in the Division of Clinical Laboratory Science at The University of North Carolina at Chapel Hill’s School of Medicine. She obtained a Master of Education and PhD in Educational Psychology from Temple University. She is the author of numerous hematology-related publications.

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This course is part of:
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collection of sweat into macroduct_edit
digital chloridometer_edit