Laboratory performance of sweat conductivity for the screening of cystic fibrosis

2018 ◽  
Vol 56 (4) ◽  
pp. 554-559 ◽  
Author(s):  
Ronda F. Greaves ◽  
Lisa Jolly ◽  
John Massie ◽  
Sue Scott ◽  
Veronica C. Wiley ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Quality Assurance ◽  
Royal College ◽  
English Language ◽  
Sweat Rate ◽  
Proper Action ◽  
Laboratory Performance ◽  
Reporting Practices ◽  
Sweat Chloride ◽  
Sweat Testing

Abstract Background: There are several complementary English-language guidelines for the performance of the sweat chloride test. These guidelines also incorporate information for the collection of conductivity samples. However, recommendations for the measurement and reporting of sweat conductivity are less clear than for sweat chloride. The aim of the study was to develop an understanding of the testing and reporting practices of sweat conductivity in Australasian laboratories. Methods: A survey specifically directed at conductivity testing was sent to the 12 laboratories registered with the Royal College of Pathologists of Australasia Quality Assurance Programs. Results: Nine (75%) laboratories participated in the survey, seven of whom used Wescor Macroduct® for collecting sweat and the Wescor SWEAT·CHEK™ for conductivity testing, and the remaining two used the Wescor Nanoduct®. There was considerable variation in frequency and staffing for this test. Likewise, criteria about which patients it was inappropriate to test, definitions of adequate collection sweat rate, cutoffs and actions recommended on the basis of the result showed variations between laboratories. Conclusions: Variations in sweat conductivity testing and reporting reflect many of the same issues that were revealed in sweat chloride test audits and have the potential to lead to uncertainty about the result and the proper action in response to the result. We recommend that sweat testing guidelines should include clearer statements about the use of sweat conductivity.

Negative Effects of Oral Fatty Acid Supplementation on Sweat Chloride in Cystic Fibrosis

PEDIATRICS ◽  
1979 ◽  
Vol 64 (1) ◽  
pp. 50-52
Author(s):  
John D. Lloyd-Still ◽  
Stuart H. Simon ◽  
Hans U. Wessel ◽  
Lewis E. Gibson
Keyword(s):  
Cystic Fibrosis ◽  
Fatty Acid ◽  
Sweat Rate ◽  
Chloride Concentration ◽  
Control Group ◽  
Safflower Oil ◽  
Negative Effects ◽  
Fatty Acid Supplementation ◽  
Acid Supplementation ◽  
Sweat Chloride

Essential fatty acid supplementation with oral safflower oil (1 gm/kg/day) to 11 cystic fibrosis patients (aged 6 months to 14 years) for one year produced no significant change in sweat chloride concentration (mEq/liter) or sweat rate (gm/min/m2). Addition of vitamin E (10 mg/kg/day) to the safflower oil had no effect on sweat chloride concentration or rate compared to placebo. No clinical improvement could be detected compared to a control group. These results do not support previous reports of the effects of fatty acid supplementation on sweat electrolyte concentrations in cystic fibrosis.

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.

scholarly journals Cystic fibrosis with normal sweat chloride concentration: case report

2003 ◽  
Vol 58 (5) ◽  
pp. 260-262 ◽  
Author(s):  
Luiz Vicente Ferreira da Silva Filho ◽  
Maria Helena de Carvalho Ferreira Bussamra ◽  
Cleyde Miriam Aversa Nakaie ◽  
Fabíola Villac Adde ◽  
Joaquim Carlos Rodrigues ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Genetic Disease ◽  
Gold Standard ◽  
Diagnostic Tests ◽  
Chloride Concentration ◽  
Rapid Decrease ◽  
Compound Heterozygous ◽  
Sweat Chloride ◽  
Sweat Testing ◽  
Chloride Concentrations

Cystic fibrosis is a genetic disease usually diagnosed by abnormal sweat testing. We report a case of an 18-year-old female with bronchiectasis, chronic P. aeruginosa infection, and normal sweat chloride concentrations who experienced rapid decrease of lung function and clinical deterioration despite treatment. Given the high suspicion ofcystic fibrosis, broad genotyping testing was performed, showing a compound heterozygous with deltaF508 and 3849+10kb C->T mutations, therefore confirming cystic fibrosis diagnosis. Although the sweat chloride test remains the gold standard for the diagnosis of cystic fibrosis, alternative diagnostic tests such as genotyping and electrophysiologic measurements must be performed if there is suspicion of cystic fibrosis, despite normal or borderline sweat chloride levels.

Outcomes of Cystic Fibrosis Screening–Positive Infants With Inconclusive Diagnosis at School Age

PEDIATRICS ◽  
2021 ◽  
Author(s):  
Tanja Gonska ◽  
Katherine Keenan ◽  
Jacky Au ◽  
Annie Dupuis ◽  
Mark A. Chilvers ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Chloride Concentration ◽  
Predictive Biomarkers ◽  
School Age ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Sweat Chloride ◽  
Sweat Testing ◽  
Prospective Longitudinal ◽  
Cystic Fibrosis Transmembrane

BACKGROUND AND OBJECTIVES Cystic fibrosis (CF) screen–positive infants with an inconclusive diagnosis (CFSPID) are infants in whom sweat testing and genetic analysis does not resolve a CF diagnosis. Lack of knowledge about the health outcome of these children who require clinical follow-up challenges effective consultation. Early predictive biomarkers to delineate the CF risk would allow a more targeted approach to these children. METHODS Prospective, longitudinal, multicenter, Canada-wide cohort study of CF positive–screened newborns with 1 to 2 cystic fibrosis transmembrane conductance regulator gene variants, of which at least 1 is not known to be CF-causing and/or a sweat chloride between 30 and 59 mmol/L. These were monitored for conversion to a CF diagnosis, pulmonary, and nutritional outcomes. RESULTS The mean observation period was 7.7 (95% confidence interval 7.1 to 8.4) years. A CF diagnosis was established for 24 of the 115 children with CFSPID (21%) either because of reinterpretation of the cystic fibrosis transmembrane conductance regulator genotype or because of increase in sweat chloride concentration ≥60 mmol/L. An initial sweat chloride of ≥40 mmol/l predicted conversion to CF on the basis of sweat testing. The 91 remaining children with CFSPID were pancreatic sufficient and showed normal growth until school age. Pulmonary function as well as lung clearance index in a subgroup of children with CFSPID were similar to that of healthy controls. CONCLUSIONS Children with CFSPID have good nutritional and pulmonary outcomes at school age, but rates of reclassifying the diagnosis are high. The initial sweat chloride test can be used as a biomarker to predict the risk for CF in CFSPID.

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.

ΔF508 Genotype Does Not Predict Disease Severity in an Ethnically Diverse Cystic Fibrosis Population

PEDIATRICS ◽  
1994 ◽  
Vol 93 (1) ◽  
pp. 114-118
Author(s):  
Lucille A. Lester ◽  
Jerome Kraut ◽  
John Lloyd-Still ◽  
Theodore Karrison ◽  
Carol Mott ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Disease Severity ◽  
Ethnically Diverse ◽  
Clinical Parameter ◽  
Population Based ◽  
Age At Diagnosis ◽  
Chest Roentgenogram ◽  
Sweat Chloride ◽  
Cystic Fibrosis Population ◽  
Cftr Mutations

Objective. As part of a study to determine population-based frequencies of CFTR mutations in an ethnically diverse, midwestern cystic fibrosis (CF) population, clinical histories were studied in 119 CF patients. Methodology. We sought to examine the association between genotype as characterized by the ΔF508 and 11 other commonly occurring mutations and clinical parameters including age at diagnosis, clinical presentation, sweat chloride level, chest roentgenogram score, clinical scores, pulmonary function test results, percent weight for height, and presence of associated CF complications. Results. Age at diagnosis of CF was significantly associated with homozygosity for ΔF508 (mean age at diagnosis ± SE: 1.7 ± 0.3 years for ΔF508/ΔF508 vs 3.9 ± 0.9 years for ΔF508/other and other/other; P = .03). No other age-adjusted clinical parameter was significantly associated with ΔF508 or any other genotype. Conclusion. These data suggest that in this sample of CF patients, ΔF508 genotype is not predictive of disease severity. The lack of association between disease severity and genotype in this ethnically diverse sample may reflect the presence of more severe undetected mutations in our sample, or the effects of modifying genes at other, non-CF loci.

Rectal organoid morphology analysis (ROMA) as a promising diagnostic tool in cystic fibrosis

Thorax ◽  
2021 ◽  
pp. thoraxjnl-2020-216368
Author(s):  
Senne Cuyx ◽  
Anabela Santo Ramalho ◽  
Nikky Corthout ◽  
Steffen Fieuws ◽  
Eva Fürstová ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Image Analysis ◽  
Diagnostic Tool ◽  
Automated Image Analysis ◽  
Sweat Chloride ◽  
Morphology Analysis ◽  
Morphological Differences ◽  
Two Parameters ◽  
Analysis Protocol

Diagnosing cystic fibrosis (CF) when sweat chloride is not in the CF range and less than 2 disease-causing CFTR mutations are found requires physiological CFTR assays, which are not always feasible or available. We developed a new physiological CFTR assay based on the morphological differences between rectal organoids from subjects with and without CF. In organoids from 167 subjects with and 22 without CF, two parameters derived from a semi-automated image analysis protocol (rectal organoid morphology analysis, ROMA) fully discriminated CF subjects with two disease-causing mutations from non-CF subjects (p<0.001). ROMA, feasible at all ages, can be centralised to improve standardisation.

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