Sweat testing for cystic fibrosis: Errors associated with the in-situ sweat test using chloride ion selective electrodes

1977 ◽  
Vol 80 (2) ◽  
pp. 333-338 ◽  
Author(s):  
P.T. Bray ◽  
G.C.F. Clark ◽  
G.J. Moody ◽  
J.D.R. Thomas
Keyword(s):  
Cystic Fibrosis ◽  
Chloride Ion ◽  
Sweat Test ◽  
Ion Selective Electrodes ◽  
Sweat Testing

Chronic Sinusitis and a Negative Sweat Test in a Patient with Cystic Fibrosis

1995 ◽  
Vol 9 (4) ◽  
pp. 225-228 ◽  
Author(s):  
Todd T Kingdom ◽  
Kelvin C. Lee ◽  
Gerd J. Cropp
Keyword(s):  
Cystic Fibrosis ◽  
Unusual Case ◽  
Dna Analysis ◽  
Chronic Sinusitis ◽  
Carrier State ◽  
Sweat Test ◽  
Genetic Mutations ◽  
Dna Mutation ◽  
Sweat Chloride ◽  
Sweat Testing

The diagnosis of cystic fibrosis (CF) is based on sweat chloride and DNA mutation testing. A subset of CF patients may have normal sweat chloride levels, thus requiring DNA analysis for confirmation of the diagnosis. These patients may escape diagnosis if sweat testing is the only modality used for screening. Recently, the putative structural gene for CF was localized to chromosome 7. The delta-F508 mutation accounts for approximately 70% of the CF chromosomes identified in North American Caucasians. Over 400 identified mutations constitute the remainder. It is now possible to screen patients for the presence of many of these genetic mutations, thus establishing the diagnosis of CF or defining a carrier state. We report an unusual case of a 17-year-old male with chronic sinusitis, mild pulmonary disease, and pancreatic sufficiency with nondiagnostic sweat chloride levels diagnosed to have CF after DNA analysis. This technique may thus serve as an important tool that pediatricians and otolaryngologists can use to diagnose children suspected of having CF.

Implementation of a Quality Improvement Program to Improve Sweat Test Performance in a Pediatric Hospital

2014 ◽  
Vol 138 (7) ◽  
pp. 920-922 ◽  
Author(s):  
Barina Aqil ◽  
Aaron West ◽  
Michael Dowlin ◽  
Estella Tam ◽  
Cristy Nordstrom ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Quality Improvement ◽  
Test Performance ◽  
Sweat Test ◽  
Pediatric Hospital ◽  
Improvement Program ◽  
Sweat Chloride ◽  
Sweat Production ◽  
Sweat Testing ◽  
Set Up

Context.—All positive screening of newborns for cystic fibrosis using the dried blood spot 2-tiered immunoreactive trypsinogen/DNA method requires subsequent sweat chloride testing for confirmation. Obtaining an adequate volume of sweat to measure chloride is a challenge for many cystic fibrosis centers across the nation. The standard for patients older than 3 months is less than 5% quantity not sufficient (QNS) and for patients 3 months or younger is less than 10% QNS. Objective.—To set up a quality improvement (QI) program for sweat testing to improve QNS rates using the Wescor Macroduct (Wescor, Inc, Logan, Utah) method at Texas Children's Hospital's laboratory, Houston, Texas. Design.—Single-center study. Results.—Quantity not sufficient rates were evaluated for 4 months before and 8 months after implementation of the QI program for patients aged 3 months or younger and those older than 3 months. The QI program included changes in technician training, service, site of collection, mode of collection, weekly review, and forms to screen patients for medications that may alter sweat production. A marked improvement was observed in the rates of QNS, which declined considerably from 16.7% to 8.5% (≤3 months old) and from 9.3% to 2.2% (>3 months old) after implementation of the QI initiative in both age categories. Conclusion.—This report demonstrates the effectiveness of the QI program in significantly improving QNS rates in sweat chloride testing in a pediatric hospital.

Cystic Fibrosis Diagnosis in Newborns, Children, and Adults

2019 ◽  
Vol 40 (06) ◽  
pp. 701-714 ◽  
Author(s):  
Carlo Castellani ◽  
Barry Linnane ◽  
Iwona Pranke ◽  
Federico Cresta ◽  
Isabelle Sermet-Gaudelus ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Clinical Presentation ◽  
Clinical Symptoms ◽  
Ex Vivo ◽  
Sweat Test ◽  
Intestinal Epithelia ◽  
Sweat Testing ◽  
Cftr Protein ◽  
Cf Transmembrane Conductance Regulator

AbstractThe diagnosis of cystic fibrosis (CF) has traditionally relied on the presence of clinical features of the disease. Today, diagnosis through newborn screening (NBS) is becoming the standard of modern CF care. CF NBS programs can identify CF prior to clinical presentation, but for the advantages of an early diagnosis to accrue a scrupulous system must be in place to ensure all steps in the program are performing. As we move rapidly into the era of CF transmembrane conductance regulator (CFTR) protein modulators, the opportunity to start a presymptomatic infant, identified through CF NBS, on these agents offers the prospect of true disease-modifying interventions which could result in a paradigm shift in CF care.Conversely, the introduction of NBS has resulted in many children being asymptomatic at the time of diagnosis. Some screened newborns are classified as “CF Screening Positive, Inconclusive Diagnosis”, or “CFTR-related metabolic syndrome” when the diagnosis can neither be confirmed nor excluded. Appropriate assessment and follow-up should be arranged at specialist centers as a proportion of these infants and adults will eventually be diagnosed with CF.Symptoms and signs are particularly pertinent when considering a diagnosis of CF outside the context of NBS. In older patients with a late diagnosis, the spectrum of clinical presentation can be very variable with vigilant clinicians from multiple specialties suspecting the diagnosis in conditions such as recurrent pulmonary infections, male infertility, pancreatitis, nasal polyposis, and malabsorption.In addition to clinical symptoms or positive NBS results, sweat test and genetic analysis are cornerstones in the diagnosis of CF, but in some cases the diagnosis cannot be confirmed on genetic or sweat testing. Difficult diagnosis may be supported by in vivo or ex vivo electrophysiology measurements on respiratory or intestinal epithelia. This can be done by either measuring transepithelial nasal potential difference or intestinal current measurements.

scholarly journals Sweat Testing and Recent Advances

2021 ◽  
Vol 9 ◽  
Author(s):  
Yasemin Gokdemir ◽  
Bulent Taner Karadag
Keyword(s):  
Cystic Fibrosis ◽  
Newborn Screening ◽  
Diagnostic Test ◽  
Genetic Disease ◽  
Clinical Findings ◽  
Caucasian Population ◽  
Test Method ◽  
Sweat Test ◽  
Recent Advances ◽  
Sweat Testing

Cystic fibrosis (CF) is the most common fatal genetic disease of the Caucasian population. Sweat testing is the principal diagnostic test for CF, and it is used for the evaluation of infants with positive CF newborn screening (NBS) and in patients with clinical findings suggesting CF. This article describes the classical sweat test method in detail and also provides an overwiew of recent advances.

scholarly journals Cystic fibrosis in disguise – the wolf in sheep’s clothing, a case report

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Friederike Wilbert ◽  
Sarah C. Grünert ◽  
Andrea Heinzmann ◽  
Sebastian F. N. Bode
Keyword(s):  
Cystic Fibrosis ◽  
Systemic Disease ◽  
Gastrointestinal Symptoms ◽  
Chloride Concentration ◽  
Failure To Thrive ◽  
Sweat Test ◽  
Upper Airways ◽  
Inborn Errors ◽  
Hepatic Involvement ◽  
Number Of Patients

Abstract Background Childhood hypoglycemia in combination with hepatomegaly is suspicious for inborn errors of metabolism. Cystic fibrosis typically presents with failure to thrive, pulmonary and gastrointestinal symptoms. Hepatic involvement and hypoglycemia can occur in a significant number of patients, although hepatomegaly is uncommon. Case presentation A 28 months old boy was presented with recurrent upper airways infections, progressive lethargy and weight loss. Clinically hepatomegaly was the main presenting feature and hypoglycemia (minimum 1.4 mmol/l) was noted as were elevated transaminases. The patient did not produce enough sweat to analyze it. Infectious causes for hepatitis were excluded and a broad metabolic work-up initiated. A therapy with starch was initiated to control hypoglycemia. In further course loose stools were reported and pancreatic elastase was found to be reduced. A further sweat test yielded pathological chloride concentration and genetic testing confirmed the diagnosis of cystic fibrosis. Conclusions Cystic fibrosis is a systemic disease and less common presentations need to be considered. Even in the age of CF-newborn screening in many countries CF needs to be ruled out in typical and atypical clinical presentations and diagnostics need to be repeated if inconclusive.

Adult Cystic Fibrosis Presenting with Nasal Polyposis and Chronic Sinusitis

1994 ◽  
Vol 8 (5) ◽  
pp. 237-240 ◽  
Author(s):  
Erica R. Thaler ◽  
Sean M. Smullen ◽  
David W. Kennedy
Keyword(s):  
Cystic Fibrosis ◽  
Nasal Polyposis ◽  
Chronic Sinusitis ◽  
Sweat Testing ◽  
General Aspects ◽  
Recurrent Nasal Polyposis

The diagnosis of cystic fibrosis is important to the otolaryngologist because of the association with chronic sinusitis and nasal polyposis. Eighty-five percent of patients are diagnosed under the age of 15, and diagnosis beyond age 20 is uncommon. We present two patients over 35 years of age in whom the diagnosis of cystic fibrosis was made during the course of workup and treatment for recurrent nasal polyposis and chronic sinusitis. To our knowledge, only one prior such case has been reported. This paper will provide a brief overview of the general aspects of the disease, discuss otolaryngic manifestations and management, and recommend indications for sweat testing in the adult.

Sign in / Sign up

Export Citation Format

Share Document