Sweat Testing For Cystic Fibrosis Research Articles

Functional endoscopic sinus surgery (FESS) with navigation system in childhood – our experience. Presentation of clinical cases

Introduction: Functional endoscopic sinus surgery (FESS) is the gold minimally invasive standard in diagnosing and surgically treating many diseases of the nose and paranasal cavities. An advantage of FESS is the possibility of application in all age groups. Materials and methods: We observed pediatric patients attended the Otorhinolaryngology Clinic in the University Hospital “Dr. Georgi Stranski” – Pleven in 2021. FESS surgery was performed in the “Integrated interdisciplinary operating unit with navigation and telesurgery systems” at the Center of competence on personalised medicine, 3D and telemedicine, robotic and minimally invasive surgery „Leonardo da Vinci” in Medical University – Pleven. Clinical cases: Case 1: A 7-year-old male patient with orbital complication of rhinosinusitis, with left orbital preseptal cellulitis, without ophthalmoplegia or loss of vision, + ptosis of the eyelid and data on pansinuitis from CT images. Performed FESS found lysis of lamina papyracea with involvement of anterior and posterior ethmoidal cells. Postoperative treatment was done with Ceftriaxone 1g/12h i.v. for 7 days, nasal glucocorticoids and antihistamines. Case 2: A 17-year-old female patient with suggested primary ciliary dyskinesia with a recurrent rhinosinusitis, persistent nasal obstruction, and thick viscous secretions that did not respond to conservative treatment. Sweat test for cystic fibrosis (-). FESS reshaping of the natural openings of the maxillary sinuses and anterior ethmoidectomy were performed bilaterally. Conclusion: FESS is a minimally invasive method, which is suitable for application in pediatric patients. When applied by trained professionals, FESS with an integrated navigation system is optimal for the diagnosis and surgical treatment of chronic and acute rhinosinusitis in children.

A simple sweat test for cystic fibrosis

A simple sweat test for cystic fibrosis

Sweat test for cystic fibrosis: Wearable sweat sensor vs. standard laboratory test

BackgroundSweat chloride testing for diagnosis of cystic fibrosis (CF) involves sweat induction, collection and handling, and measurement in an analytical lab. We have developed a wearable sensor with an integrated salt bridge for real-time measurement of sweat chloride concentration. Here, in a proof-of-concept study, we compare the performance of the sensor to current clinical practice in CF patients and healthy subjects. MethodSweat was induced on both forearms of 10 individuals with CF and 10 healthy subjects using pilocarpine iontophoresis. A Macroduct sweat collection device was attached to one arm and sweat was collected for 30 min and then sent for laboratory analysis. A sensor was attached to the other arm and the chloride ion concentration monitored in real time for 30 min using a Bluetooth transceiver and smart phone app. ResultsStable sweat chloride measurements were obtained within 15 min following sweat induction using the wearable sensor. We define the detection time as the time at which the standard deviation of the real-time chloride ion concentration remained below 2 mEq/L for 5 min. The sweat volume for sensor measurements at the detection time was 13.1 ± 11.4 μL (SD), in many cases lower than the minimum sweat volume of 15 μL for conventional testing. The mean difference between sweat chloride concentrations measured by the sensor and the conventional laboratory practice was 6.2 ± 9.5 mEq/L (SD), close to the arm-to-arm variation of about 3 mEq/L. The Pearson correlation coefficient between the two measurements was 0.97 highlighting the excellent agreement between the two methods. ConclusionA wearable sensor can be used to make real-time measurements of sweat chloride within 15 min following sweat induction, requiring a small sweat volume, and with excellent agreement to standard methods.

The Italian pilot external quality assessment program for cystic fibrosis sweat test

ObjectivesSweat chloride test is the gold standard test for cystic fibrosis (CF) diagnosis. In 2014 the Istituto Superiore di Sanità established the Italian pilot external quality assessment program for CF sweat test (IEQA-ST). Design and methodsTen laboratories, included among the 33 Italian CF Referral Centers, were selected and enrolled on the basis of their attitude to perform sweat test (ST) analysis by using methods recommended by the Italian Guidelines. They received three different sweat-like samples (normal, borderline and pathologic chloride concentration), with mock clinical indications, for analysis according to routine procedures. Assessment, performed by a panel of experts, covered analytical performance, interpretation and reporting of results; categories of “poor” and “satisfactory” performance were not defined. All data were managed through a web utility. ResultsThe program identified important areas of interest and, in some case, of concern. It is important to underline that results are referred to a small proportion, i.e. about 30%, of Italian laboratories performing CF ST in the context of the Referral Centers. ConclusionsData collected highlight the importance of participation in EQA programs as it may improve laboratory/clinical performance; our study represents a model for the setting up of a large-scale EQA scheme for ST.

Lack of harmonization in sweat testing for cystic fibrosis – a national survey

Introduction. Sweat testing is used in the diagnosis of cystic fibrosis. Interpretation of the sweat test depends, however, on the method performed since conductivity, osmolality and chloride concentration all can be measured as part of a sweat test. The aim of this study was to investigate how performance of the test is organized in Denmark. Methods. Departments conducting the sweat test were contacted and interviewed following a premade questionnaire. They were asked about methods performed, applied NPU (Nomenclature for Properties and Units) code, reference interval, recommended interpretation and referred literature. Results. 14 departments performed the sweat test. One department measured chloride and sodium concentration, while 13 departments measured conductivity. One department used a non-existing NPU code, two departments applied NPU codes inconsistent with the method performed, four departments applied no NPU code and seven applied a correct NPU code. Ten of the departments measuring conductivity applied reference intervals. Nine departments measuring conductivity had recommendations of a normal area, a grey zone and a pathological value, while four departments only applied a normal and grey zone or a pathological value. Cut-off values for normal, grey and pathological areas were like the reference intervals inconsistent. Conclusion. There is inconsistent use of NPU codes, reference intervals and interpretation of sweat conductivity used in the process of diagnosing cystic fibrosis. Because diagnosing cystic fibrosis is a combined effort between local pediatric departments, biochemical and genetic departments and cystic fibrosis centers, a national harmonization is necessary to assure correct clinical use.

Sixty-five years since the New York heat wave: Advances in sweat testing for cystic fibrosis

The sweat test remains important as a diagnostic test for cystic fibrosis (CF) and has contributed greatly to our understanding of CF as a disease of epithelial electrolyte transport. The standardization of the sweat test, by Gibson and Cooke [Gibson and Cooke (1959) Pediatrics 1959;23:5], followed observations of excessive dehydration amongst patients with CF and confirmed the utility as a diagnostic test. Quantitative pilocarpine iontophoresis remains the gold standard for sweat induction, but there are a number of collection and analytical methods. The pathophysiology of electrolyte transport in sweat was described by Quinton [Quinton (1983) Nature 1983;301:421-422], and this complemented the developments in genetics that discovered the cystic fibrosis transmembrane conductance regulator (CFTR), an epithelial-based electrolyte transport protein. Knowledge of CF has since increased rapidly and further developments in sweat testing include: new collection methods, further standardization of the technique with international recommendations and age related reference intervals. More recently, sweat chloride values have been used as proof of effect for the new drugs that activate CFTR. However, there remain issues with adherence to sweat test guidelines in many countries and there are gaps in our knowledge, including reference intervals for some age groups and stability of sweat samples in transport. Furthermore, modern methods of elemental quantification need to be explored as alternatives to the original analytical methods for sweat electrolyte measurement. The purpose of this review is therefore to describe the development of the sweat test and consider future directions.

A Patient With Pancreas Divisum, Recurrent Acute Pancreatitis, and Homozygosity for the Cystic Fibrosis Transmembrane Regulator–Associated Protein 5T Allele

Mutations in the gene encoding the cystic fibrosis transmembrane regulator (CFTR) have been reported to increase the risk of recurrent acute pancreatitis in patients with pancreas divisum. We assessed the CFTR gene in a young male patient with pancreas divisum and recurrent acute pancreatitis. Magnetic resonance cholangiopancreatography and computed tomography revealed that the patient had pancreas divisum, with an enlarged and tortuous pancreatic duct; he also had positive results from the cystic fibrosis sweat test. Genetic analysis did not identify any common CFTR mutations, but did show that he was homozygous for the 5T allele in intron 8 IVS8 5T-12TG (which affects splicing at intron 8). Endoscopic sphincterotomy and stenting of papilla minor was performed. The IVS8 5T-12TG variant has been associated with abnormal organ development, therefore it is possible that CFTR has an important role in the development of the pancreatic duct. We propose this patient has recurrent acute pancreatitis resulting from a developmental defect associated with a suboptimal CFTR function.

Multiple Brain Abscesses Associated With Tongue Piercing

PREVIOUSLYHEALTHY22-YEAR-OLDMANWAS referredtoourinstitutionbyanotherhospitalbecauseofhighfever,drowsiness,and multiplering-enhancinglesionsonbrain computedtomography(CT).Medicalhistory was unremarkable, except for a tongue piercing the patienthadgotten2weeksearlier.Onhospitaladmission, globalaphasiaandrighthemiplegiawerefound.Histemperaturewas39°C,andhiswhitebloodcellcountshowed leukocytosis with a left shift. The patient was given empiricalantibiotictreatment.Magneticresonanceimaging of the brain revealed 13 ring enhancement lesions with surroundingedema,withfocalbleedinginsomeofthem (Figure). Results of an extensive clinical and laboratory workup, including abdominal CT, transesophageal echocardiography, immunoelectrophoresis, complement levels, antinuclear antibody test, human immunodeficiency virus test, and sweat test for cystic fibrosis, were negative, whilechestCTshowedlocalbronchiectasesontheleftlower lobe.Biopsyaspirationfromoneofthebrainlesionsrevealed

Sweat testing for cystic fibrosis: How good is your laboratory?

Sweat testing for cystic fibrosis: How good is your laboratory?

Sweat testing for cystic fibrosis: A review of New Zealand laboratories

Evolving diagnostic criteria for cystic fibrosis, broadening of the populations being tested and the need to interpret intermediate sweat test results have imposed a much greater need to standardize the collection and analysis of sweat. To identify variations in sweat testing in New Zealand laboratories and compare these with guidelines from the UK and the USA. All laboratories in New Zealand offering sweat testing were identified and data collected from these laboratories by structured questionnaire. There were no New Zealand laboratories that conformed to either set of guidelines. Inconsistencies were observed in minimum sweat quantities, the nature of the iontophoresis solution, the sweat electrolytes analysed, quoted reference ranges and recommendations made as a consequence of the result. Conformity to the guidelines would help to minimize variation in sweat testing in New Zealand. Performance of a sufficient number of tests to maintain expertise is critical, but geographical constraints make patient travel to distant centres difficult in a small, scattered population. A possible solution, where numbers permit, may be the collection of sweat locally, with referral to a major laboratory for analysis. This is only possible with adequate training in collection and follow-up audit of the sweat testing procedure both in the collection and in the analytical phase.

Birth After Preimplantation Diagnosis of the Cystic Fibrosis △F508 Mutation by Polymerase Chain Reaction in Human Embryos Resulting From Intracytoplasmic Sperm Injection With Epididymal Sperm

Men with congenital bilateral absence of the vas deferens (CBAVD) have been regarded as presenting a mild form of cystic fibrosis (CF). In this article, we report a case of male-factor infertility, in which both partners are carriers of the delta F508 mutation and the male partner has CBAVD. Microsurgical epididymal sperm aspiration (MESA) was performed to obtain spermatozoa; intracytoplasmic sperm injection (ICSI) was carried out on the oocytes since the motility of the spermatozoa was severely impaired; and embryo biopsy and a polymerase chain reaction (PCR) were carried out for preimplantation diagnosis of the CF delta F508 mutation. Single-blastomere analysis was performed and indicated that two embryos were affected (homozygous delta F508) and three embryos were carriers. After transfer of the latter three embryos, a singleton pregnancy was established. At amniocentesis, the delta F508 carrier status of the fetus with a 46, XY karyotype was confirmed. A healthy boy was born and the presence of vasa deferentia, bilaterally, was confirmed. The CF sweat test was also normal. Successful fertilization can be obtained by combination of MESA and ICSI in patients with CBAVD. Preimplantation diagnosis of CF is indicated. Pregnancy and birth of normal children can ensue in such patients.

Trends and Methodology in Sweat Testing for Cystic Fibrosis

The diagnosis of cystic fibrosis (CF) depends on a carefully performed sweat test using reliable methodology. This article describes the current status of sweat testing methodology in North Carolina and compares it with results from a study done more than a decade ago. While the less reliable chloride electrode remains the most popular method for sweat testing, more sweat tests are performed annually using the CF Foundation approved methods of GCQPIT and Macroduct. In many hospital laboratories, the concern for accurate testing has lead to quality assurance procedures for the sweat test.

Diagnostic Delay in Duchenne's Muscular Dystrophy and Cystic Fibrosis

<h3>To the Editor.—</h3> In an analysis of diagnostic delays in patients with Duchenne's muscular dystrophy (DMD), Crisp et al (1982;247:478) found that the average elapsed time between initial parental concern and final diagnosis was 3.0 years. These delays occurred even though massive elevation of serum creatine kinase levels is a reliable biochemical marker for the early detection of DMD. It is of interest to note the similarities between DMD, which is transmitted as an X-linked recessive, and cystic fibrosis (CF), which is transmitted as an autosomal recessive. In the case of both diseases, the basic defect is unknown, there is no specific therapy, a reliable test is available for early diagnosis (sweat test for CF), the course is marked by recurrent pulmonary infections and eventual respiratory failure, and average survival is 20 years. There is also a similarity in diagnostic delays. We have reviewed the records of 194 patients with

The Sweat Test for Cystic Fibrosis: Improving Its Reliability

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The sweat test for cystic fibrosis

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Sweat Tests

<h3>To the Editor.—</h3> I feel obliged to reply to Dr Shwachmann's letter (240:2731, 1978) regarding the high frequency of unreliable sweat tests for cystic fibrosis and his statement that the cause is the lack of interest of clinical chemists. I agree that sweat tests are frequently not performed reliably, but I wonder why the clinical chemist has been singled out as being responsible when most hospital laboratories are still directed by pathologists and not by professional clinical chemists. Certainly in our laboratory the sweat test is performed exactly as described by the Cystic Fibrosis Foundation in its publication,<i>Procedure for the Quantitative Iontophoretic Sweat Test for Cystic Fibrosis</i>, by Gibson, Sant' Agnese, and Shwachmann. We report the weight of sweat collected and the concentration of sodium and chloride and run the test twice. In addition to our laboratory, I know of many other hospital clinical chemistry laboratories in which the

Sweat tests

<h3>To the Editor.—</h3> I feel obliged to reply to Dr Shwachmann's letter (240:2731, 1978) regarding the high frequency of unreliable sweat tests for cystic fibrosis and his statement that the cause is the lack of interest of clinical chemists. I agree that sweat tests are frequently not performed reliably, but I wonder why the clinical chemist has been singled out as being responsible when most hospital laboratories are still directed by pathologists and not by professional clinical chemists. Certainly in our laboratory the sweat test is performed exactly as described by the Cystic Fibrosis Foundation in its publication,<i>Procedure for the Quantitative Iontophoretic Sweat Test for Cystic Fibrosis</i>, by Gibson, Sant' Agnese, and Shwachmann. We report the weight of sweat collected and the concentration of sodium and chloride and run the test twice. In addition to our laboratory, I know of many other hospital clinical chemistry laboratories in which the

Sweat testing for cystic fibrosis. Diagnostic screening with a combination chloride ion-selective electrode.

Screening of sweat chloride in newborn infants with the Orion Skin Chloride Measuring System and incorporating some procedural innovations is described. The results indicate that while diagnostic screening for cystic fibrosis can be readily undertaken, the test with the chloride ion-selective electrode is best left at least to the second day of life or later because of insufficient sweating in very young babies. Measurements on 2 babies with cystic fibrosis are also discussed.

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

The in-situ sweat test is prone to errors from various sources. This paper examines errors due to evaporation, absorption of water into the skin, and pressure of the electrode on the skin. Only evaporation caused serious errors. The accuracy and precision when measuring small chloride/sweat samples on the skin are not significantly worse than when measuring bulk solutions.

Sweat testing for cystic fibrosis: Characteristics of a combination chloride ion-selective electrode

Filling solution leakage, reproducibility, stability, interferences and temperature effects have been studied in relation to the use of the Orion 96-17-01 combination chloride ion-selective electrode in sweat testing for cystic fibrosis. While stability and reproducibility is good, certain antiseptic systems and especially Hibitaine (chlorhexidine gluconate) interfere with the electrode and therefore need to be absent during sweat testing. Temperature conditions during calibration and sweat testing need to be controlled in view of the extent of response variations for even modest temperature differences between sensor-skin interface and electrode stem.