Cystic fibrosis newborn screening: outcome of infants with normal sweat tests

2017 ◽  
Vol 103 (8) ◽  
pp. 753-756 ◽  
Author(s):  
Claire Edmondson ◽  
Christopher Grime ◽  
Ammani Prasad ◽  
Jacqui Cowlard ◽  
Chinedu E C Nwokoro ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Newborn Screening ◽  
Genome Sequencing ◽  
Dna Analysis ◽  
Gene Mutations ◽  
High Serum ◽  
Sweat Test ◽  
Sweat Chloride ◽  
South East England

Newborn babies positively screened for cystic fibrosis (CF) (high serum immunoreactive trypsin (IRT) with DNA analysis) are referred for a diagnostic sweat test, which may be normal (sweat chloride <30 mmol/L). Unless two gene mutations are identified during Newborn screening (NBS), the babies are discharged from follow-up. We wished to check that none had subsequently developed symptoms suggestive of CF. We retrospectively reviewed patient notes and contacted general practitioners of all babies with a negative sweat test, conducted in one of the four paediatric specialist CF centres in London, over the first 6 years of screening in South East England.Of 511 babies referred, 95 (19%) had a normal sweat test. Five (5%) had CF diagnosed genetically, two of them on extended genome sequencing after clinical suspicion. Eleven (12%) were designated as CF screen positive inconclusive diagnosis (CFSPID); one of the five CF children was originally designated as CFSPID. Seventy-nine (83%) were assumed to be false-positive cases and discharged; follow-up data were available for 51/79 (65%); 32/51 (63%) had no health issues, 19/51 (37%) had other significant non-CF pathology.These results are reassuring in that within the limitations of those lost to follow-up, CF symptoms have not emerged in the discharged children. The high non-CF morbidity in these children may relate to known causes of high IRT at birth. Clinicians need to be aware that a child can have CF despite a normal sweat test following NBS, and if symptoms suggest the diagnosis, further testing, including extended genome sequencing, is required.

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.

scholarly journals Newborn Screening for Cystic Fibrosis: Infant and Laboratory Factors Affecting Successful Sweat Test Completion

2020 ◽  
Vol 7 (1) ◽  
pp. 1
Author(s):  
Ambika Shenoy ◽  
Dina Spyropoulos ◽  
Kathleen Peeke ◽  
Dawn Smith ◽  
Michael Cellucci ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Newborn Screening ◽  
Gestational Age ◽  
Diagnostic Testing ◽  
Sweat Test ◽  
Inherited Disease ◽  
Success Rates ◽  
Factors Affecting ◽  
Laboratory Staff ◽  
Sweat Chloride

Newborn screening (NBS) for Cystic Fibrosis (CF) has revolutionized the diagnosis of this inherited disease. CF NBS goals are to identify, diagnose, and initiate early CF treatment to attain better health outcomes. Abnormal CF NBS infants require diagnostic analysis via sweat chloride testing (ST). During ST, insufficient sweat volume collection causes a “quantity not sufficient” (QNS) test result and may delay CF diagnosis. The CF Foundation recommends QNS rates <10% for infants <3 months, but many CF Centers experience difficulties meeting this standard. Our quality improvement (QI) study assessed infant and laboratory factors contributing to ST success and QNS rates from 2017–2019. Infants’ day of life (DOL) at successful ST completion was analyzed according to infant factors (birth weight (BW), gestational age, ethnicity, and sex). Laboratory factors and procedures affecting ST outcomes were also reviewed. At our institution, BW and gestational age were the infant factors found to significantly affect DOL at ST completion. ST education, reduced number of laboratory technicians, and direct observation during ST completion also improved ST success rates. This study supports QI measures and partnerships between CF centers and laboratory staff to identify and improve ST QNS rates while sustaining practices to ensure timely CF diagnostic testing.

scholarly journals Cystic Fibrosis-Screening Positive Inconclusive Diagnosis: Newborn Screening and Long-Term Follow-Up Permits to Early Identify Patients with CFTR-Related Disorders

Diagnostics ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 570
Author(s):  
Alice Castaldo ◽  
Chiara Cimbalo ◽  
Raimondo J. Castaldo ◽  
Marcella D’Antonio ◽  
Manuela Scorza ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Newborn Screening ◽  
Molecular Analysis ◽  
Gene Sequencing ◽  
Sweat Test ◽  
Imaging Data ◽  
Recurrent Pneumonia ◽  
Clinical Complications

Background: Newborn screening (NBS) early-identifies cystic fibrosis (CF), but in CF-screening positive inconclusive diagnosis (CF-SPID) the results of immunoreactive trypsinogen (IRT), molecular analysis and sweat test (ST) are discordant. A percentage of CF-SPID evolves to CF, but data on long-term monitoring are lacking. We describe the follow-up of all CF and CF-SPID identified between 2008 and 2019. Methods: NBS was performed by IRT followed by molecular analysis and ST between 2008 and 2014; double IRT followed by molecular analysis and ST after 2014. Results: NBS revealed 47 CF and 99 CF-SPID newborn, a ratio 1:2.1—the highest reported so far. This depends on the identification by gene sequencing of the second variant with undefined effect in 40 CF-SPID that otherwise would have been defined as carriers. Clinical complications and pulmonary infections occurred more frequently among CF patients than among CF-SPID. Two CF-SPID cases evolved to CF (at two years), while eight evolved to CFTR-related disorders (CFTR-RD), between one and eight years, with bronchiectasis (two), recurrent pneumonia (four, two with sinonasal complications), recurrent pancreatitis (two). No clinical, biochemical or imaging data predicted the evolution. Conclusion: Gene sequencing within the NBS reveals a higher number of CF-SPID and we first describe an approach to early identify CFTR-RD, with relevant impact on their outcome.

scholarly journals Two years of newborn screening for cystic fibrosis in North Macedonia: First experience

2021 ◽  
Vol 24 (1) ◽  
pp. 41-46
Author(s):  
S Fustik ◽  
V Anastasovska ◽  
D Plaseska-Karanfilska ◽  
A Stamatova ◽  
L Spirevska ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Pilot Study ◽  
Newborn Screening ◽  
Chloride Concentration ◽  
Sweat Test ◽  
Sweat Chloride ◽  
Frequent Mutations ◽  
Cftr Mutations ◽  
The Republic ◽  
Cf Transmembrane Conductance Regulator

Abstract There is a widely accepted consensus on the benefits of newborn screening (NBS) for cystic fibrosis (CF) in terms of reduced disease severity, improved quality of life, lower treatment burden, and reduced costs. More and more countries in the world are introducing NBS for CF as a national preventive health program. Newborn screening for CF was introduced in the Republic of North Macedonia (RNM) in April, 2019, after a pilot study of 6 months in 2018. A two-step immunoreactive trysinogen (IRT-IRT) algorithm is performed, and then a sweat test for confirmation/exclusion of the CF diagnosis when the IRT values were both over the cutoff (70.0 and 45.0 ng/mL, respectively). In cases with confirmed diagnosis of CF (a sweat chloride concentration >60.0 mmol/L) or with intermediate sweat test results (a sweat chloride concentration of between 30.0 and 59.0 mmol/L), CF transmembrane conductance regulator (CFTR) mutation analysis is performed. By the end of 2020, over a period of 27 months, including the pilot study period, a total number of 43,139 newborns were screened for CF. Seventeen (0.039%) newborns were diagnosed with CF. In all newly discovered CF cases by screening, the diagnosis was confirmed by determination of the CFTR mutations. The most common CFTR mutation, F508del, was found with an overall incidence of 70.6%. Other more frequent mutations were G542X (11.8%) and N1303K (5.9%). Four mutations were found in one CFTR allele each: G1349D, G126D, 457TAT>G and CFTRdupexon22, with the last one being newly discovered with unknown consequences. An incredibly large difference was found in the incidence of the disease between the Macedonian and Albanian neonatal population, with almost four time higher prevalence among Albanians (1:4530 vs. 1:1284).

Newborn Screening for Cystic Fibrosis

PEDIATRICS ◽  
1991 ◽  
Vol 87 (6) ◽  
pp. 954-955
Author(s):  
IAN C. T. LYON ◽  
DIANNE R. WEBSTER
Keyword(s):  
Cystic Fibrosis ◽  
Newborn Screening ◽  
Elevated Level ◽  
Meconium Ileus ◽  
Screening Tests ◽  
Initial Screening ◽  
False Negatives ◽  
Immunoreactive Trypsinogen

To the Editor.— The report on newborn screening for cystic fibrosis1 illustrates the need for continued evaluation of such programs. The authors state that the identification of cases of cystic fibrosis (CF) by an elevated level of immunoreactive trypsinogen (IRT) in second (follow-up) samples from infants with positive initial screening tests could result in false negatives in 27% of cases of cystic fibrosis without meconium ileus (MI). We have screened 401 122 infants using the method originally reported.2

Cystic Fibrosis and Non-Cystic Fibrosis Bronchiectasis

2014 ◽  
Author(s):  
Michael J Stephen
Keyword(s):  
Cystic Fibrosis ◽  
Differential Diagnosis ◽  
Forced Expiratory Volume ◽  
Sweat Test ◽  
Inherited Disease ◽  
Injury Rates ◽  
Computed Tomographic ◽  
Sweat Chloride ◽  
Average Survival ◽  
Pancreatic Exocrine Deficiency

Cystic fibrosis (CF) is an autosomal recessive disease characterized by an elevated sweat chloride level, diffuse bronchiectasis, and pancreatic exocrine deficiency. It is the most common lethal inherited disease in whites. Most patients present at birth or early childhood, although later diagnoses are not infrequent. Once CF was uniformly fatal at an early age, but advances in nutrition, airway clearance, and infection management have led to an average survival of 37 years. The newest aspect of care is the advent of protein modulators, which may increase life expectancy even further. This chapter discusses the epidemiology, genetics, pathophysiology and pathogenesis, diagnosis, differential diagnosis, and treatment of CF. The definition, epidemiology, etiology, pathogenesis, diagnosis, management, and prognosis of non-CF bronchiectasis are also covered. Figures illustrate normal and abnormal CF transmembrane conductance regulators, the vicious cycle hypothesis of lung injury, rates of respiratory germs by age, the diagnosis of CF, the therapeutics pipeline for CF, forced expiratory volume in 1 second lung function percent predicted versus body mass index, and the median predicted survival age of patients with CF. A chest x-ray and chest computed tomographic scan of CF are also provided. Tables outline the most common CF mutations in 2011, class mutations of CF, a mnemonic for acute exacerbations of CF, the diagnosis of CF-related diabetes in a stable patient, sweat test values, and the differential diagnosis of bronchiectasis.This chapter contains 9 highly rendered figures, 6 tables, 143 references, 1 teaching slide set, and 5 MCQs.

Test for the Concentration of Electrolytes in Cystic Fibrosis of the Pancreas Utilizing Pilocarpine by Iontophoresis, by Lewis E. Gibson and Robert E. Cooke,Pediatrics; 1959;24:545–549

PEDIATRICS ◽  
1998 ◽  
Vol 102 (Supplement_1) ◽  
pp. 230-231
Author(s):  
Victor Chernick
Keyword(s):  
Cystic Fibrosis ◽  
Filter Paper ◽  
Direct Injection ◽  
Heat Stroke ◽  
Chloride Concentration ◽  
Hot Water ◽  
Sweat Test ◽  
High Concentration ◽  
Sweat Chloride ◽  
Plastic Bag

Aim. To develop a method for stimulating sweating that is rapid, painless, and avoids the risk of heat stress. Background. Since the discovery that there is a high concentration of sodium and chloride in the sweat of patients with cystic fibrosis of the pancreas in 1953, the sweat test has been performed by placing the patient's body in a plastic bag with or without hot water bottles to stimulate sweating. This method is unsatisfactory because of complications such as hyperpyrexia and heat stroke. Direct injection of a cholinergic agent intradermally is painful and therefore not practical. Methods. A rheostat with a milliampere meter was constructed at a cost of ∼$7 that allowed the iontophoresis of pilocarpine into the skin using negative and positive (2-cm diameter) electrocardiography electrodes. The positive electrode was placed on the flexor surface of the arm over a filter paper soaked in 0.2 mL of 0.2% pilocarpine nitrate. Current (0.2 mA) was applied for 5 minutes and then sweat was collected onto a preweighed filter paper for 30 minutes. Sweat chloride was determined by a polarographic method. Sweat tests were performed on 25 patients with cystic fibrosis (CF), 17 asymptomatic relatives and 27 control patients. Patients with CF had sweat chloride concentration &gt;80 mEq/L; relatives, 32.5 mEq/L (highest 57 mEq/L); and control subjects, 21.1 mEq/L (highest 60 mEq/L). Conclusions. The iontophoresis of pilocarpine into the skin is a rapid, painless, safe, and reliable method for stimulating sweating and facilitating the determination of sweat chloride concentration.

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