Sweat Test Results Research Articles

Comparative Study of 1444 nm Laser Monotherapy versus Integrated Liposuction in the Treatment of Axillary Osmidrosis.

Background and Objectives: The 1444 nm wavelength Neodymium:Yttrium-Aluminum-Garnet (Nd:YAG) laser treatment is an efficient method for treating axillary osmidrosis (AO); however, it has a relatively low treatment persistence. To address this issue, we performed integrated liposuction surgery with a laser to treat AO and compared the results with those of a group treated only with a laser. Materials and Methods: This study compared the outcomes of AO treatment between the two groups up to six months postoperatively. The first group of 18 patients underwent laser treatment alone, and the second group of 12 patients underwent integrated liposuction surgery in addition to laser treatment. Outcomes were assessed using the following variables: degree of malodor (DOM), sweating area, patient satisfaction, pain levels, and complications, such as burns, swelling, and contractures. Results: Compared to the laser-only group, the integrated liposuction group demonstrated significantly superior outcomes in terms of DOM (p = 0.002) and patient satisfaction (p = 0.006), as well as a reduction in the sweating area (p = 0.012). The pain rating was higher in the liposuction group, but the difference was not statistically significant (p = 0.054). Compared with the patients in the integrated liposuction treatment group, those in the laser treatment group exhibited a significantly higher number of burns under the axillae (p = 0.025). However, no significant differences were observed in the swelling or contracture between the groups. Conclusions: Integrated liposuction with laser therapy significantly improved treatment outcomes, including malodor, patient satisfaction, sweat test results, and decreased complication rates.

The first described pathogenic variant c.2617G>T of the CFTR gene

Cystic fibrosis (CF) is a disease caused by pathogenic variants in the CFTR gene. The greatest difficulty at the moment is assessing the contribution to the development of the disease of rare and previously unidentified genetic variants (mutations), mutations of uncertain clinical significance, as well as determining the genotype-phenotype relationship. Additional diagnostic methods are needed due to the large number of patients with borderline sweat test values. Purpose of the study: to study the pathogenicity of a newly identified variant of the nucleotide sequence of the CFTR gene based on assessing the functional activity of epithelial ion channels (ENaC, CFTR, CaCCs). Materials and methods: medical history data, method intestinal current measurement (ICM). Results: the patient had a severe course of the disease. Positive sweat test results, low fecal pancreatic elastase. The ICM method showed the absence of chlorine channel function. Conclusion: For the first time, the clinical features of a patient with the c.2617G>T genetic variant in the genotype have been described. The results of the examination and the clinical course of the disease correspond to the severe course of the disease. Additional use of the ICM method confirmed the absence of CFTR channel function in a patient carrier of this variant of the CFTR gene.

CFTR function is impaired in a subset of patients with pancreatitis carrying rare CFTR variants

BackgroundMany affected by pancreatitis harbor rare variants of the cystic fibrosis (CF) gene, CFTR, which encodes an epithelial chloride/bicarbonate channel. We investigated CFTR function and the effect of CFTR modulator drugs in pancreatitis patients carrying CFTR variants. MethodsNext-generation sequencing was performed to identify CFTR variants. Sweat tests and nasal potential difference (NPD) assays were performed to assess CFTR function in vivo. Intestinal current measurement (ICM) was performed on rectal biopsies. Patient-derived intestinal epithelial monolayers were used to evaluate chloride and bicarbonate transport and the effects of a CFTR modulator combination: elexacaftor, tezacaftor and ivacaftor (ETI). ResultsOf 32 pancreatitis patients carrying CFTR variants, three had CF-causing mutations on both alleles and yielded CF-typical sweat test, NPD and ICM results. Fourteen subjects showed a more modest elevation in sweat chloride levels, including three that were provisionally diagnosed with CF. ICM indicated impaired CFTR function in nine out of 17 non-CF subjects tested. This group of nine included five carrying a wild type CFTR allele. In epithelial monolayers, a reduction in CFTR-dependent chloride transport was found in six out of 14 subjects tested, whereas bicarbonate secretion was reduced in only one individual. In epithelial monolayers of four of these six subjects, ETI improved CFTR function. ConclusionsCFTR function is impaired in a subset of pancreatitis patients carrying CFTR variants. Mutations outside the CFTR locus may contribute to the anion transport defect. Bioassays on patient-derived intestinal tissue and organoids can be used to detect such defects and to assess the effect of CFTR modulators.

Efficacy of treatment of equine anhidrosis with acupuncture and Chinese herbs is low but higher in treated horses compared with placebo.

To assess the therapeutic efficacy of acupuncture in combination with Chinese herbs for treatment of horses affected with anhidrosis. 44 horses affected with anhidrosis for up to 3 years' duration were enrolled. Inclusion required both compatible clinical signs and results of a quantitative intradermal terbutaline sweat test. Study horses were randomly allocated into 2 groups. Group 1 (n = 19) was treated with daily Chinese herbs and 4 weekly acupuncture sessions. Group 2 (n = 25) was given daily hay powder as a placebo and 4 weekly sham acupuncture sessions. Horses were tested by quantitative intradermal terbutaline sweat test within 2 days after treatment completion and again 4 weeks following treatment. Terbutaline-induced sweat responses (mg) were not different between groups within 2 days and 4 weeks after treatment. Two days after treatment, ratios of sweat responses (compared to baseline) were higher (P < .05) in the treatment group compared to the placebo group at terbutaline concentrations of 1.0, 100, and 1,000 µg/mL. The number of horses responding to treatment was higher in the treatment group (5/19 [26%]), compared to horses in the placebo group (1/25 [4%]) for 1 of 5 terbutaline concentrations 2 days (10 µg/mL) or 4 weeks (0.1 µg/mL) after treatment. Ratios of sweat responses were higher in treatment horses 2 days after treatment, compared to baseline, but not 4 weeks later. The efficacy of a traditional Chinese veterinary medicine protocol for anhidrosis treatment with acupuncture and Chinese herbs was low but higher in treated horses compared with placebo.

Comprehensive Assessment of CFTR Modulators' Therapeutic Efficiency for N1303K Variant.

p.Asn1303Lys (N1303K) is a common missense variant of the CFTR gene, causing cystic fibrosis (CF). In this study, we initially evaluated the influence of CFTR modulators on the restoration of N1303K-CFTR function using intestinal organoids derived from four CF patients expressing the N1303K variant. The forskolin-induced swelling assay in organoids offered valuable insights about the beneficial effects of VX-770 + VX-661 + VX-445 (Elexacaftor + Tezacaftor + Ivacaftor, ETI) on N1303K-CFTR function restoration and about discouraging the prescription of VX-770 + VX-809 (Ivacaftor + Lumacaftor) or VX-770 + VX-661 (Ivacaftor + Tezacaftor) therapy for N1303K/class I patients. Then, a comprehensive assessment was conducted on an example of one patient with the N1303K/class I genotype to examine the ETI effect on the restoration of N1303K-CFTR function using in vitro the patient's intestinal organoids, ex vivo the intestinal current measurements (ICM) method and assessment of the clinical status before and after targeted therapy. All obtained results are consistent with each other and have proven the effectiveness of ETI for the N1303K variant. ETI produced a significant positive effect on forskolin-induced swelling in N1303K/class I organoids indicating functional improvement of the CFTR protein; ICM demonstrated that ETI therapy restored CFTR function in the intestinal epithelium after three months of treatment, and the patient improved his clinical status and lung function, increased his body mass index (BMI) and reduced the lung pathogenic flora diversity, surprisingly without improving the sweat test results.

Experiences of cystic fibrosis newborn screening and genetic counseling.

The South Carolina cystic fibrosis (CF) newborn screening (NBS) program changed in 2019 to include CFTR genotyping for babies with top 4% immunoreactive trypsinogen, which improves sensitivity and timeliness but increases carrier detection. Carrier identification has genetic implications for the family and parents of NBS+ babies have increased emotional distress. Genetic counseling (GC) may increase parent understanding and reduce anxiety yet is not uniformly offered at CF centers. We report our early results after implementing GC for NBS+ families at the time of sweat chloride testing based on GC availability, which resulted in an unselected GC- control arm. Sixteen mothers (GC+ = 9, GC- = 7) participated in an online survey about their experience. Responses were analyzed in aggregate and for differences between GC+ and GC- groups. All-respondent sadness and anxiety increased with notification of the NBS+ result and decreased after sweat test results. Anxiety and sadness were greater in GC- compared to GC+ until after the diagnosis was resolved, though emotional differences between the groups were not statistically significant. On a scale of 0 = not at all to 10 = extremely, GC was rated very helpful (mean 9.0, range 5-10), informative (mean 8.9, range 4-10), comforting (mean 9.1, range 6-10), and minimally distracting (mean 1.8, range 0-9). All participants correctly identified that a risk for a child to have CF exists when both parents are (at least) carriers. Delivery of NBS results to respondents varied by timing, informant, and information given. The child's pediatrician notified 10 (62.5%) of the NBS+ result. Parents felt they were notified in a timely manner (68.8%), by someone knowledgeable about NBS (62.5%), the sweat test (62.5%), CF (43.8%), and genetics (43.8%) and who cared about them (81.3%). Parents felt worried (81.3%), confused (81.3%), empowered (25%), and other (sad, shocked, scared, overwhelmed, devastated, defeated). Data from this single-center study suggest benefit of GC, that families would value earlier contact with an expert, and that prompt diagnostic resolution may reduce duration of parental distress.

Effectiveness of lumacaftor/ivacaftor in 1-year therapy of cystic fibrosis in adult patients

Introduction. Cystic fibrosis is a severe systemic multiorgan exocrinopathy, the severity of the condition in 95% cases is caused by the depth of respiratory organ damage. Symptom management drugs that were developed over more than 50 years allowed to improve survival, but average life expectancy in cystic fibrosis (CF) remains well below the general population average. Targeted therapy is the most promising treatment, which restores the chloride channel function. Lumacaftor/ivacaftor is the first targeted therapy drug authorized in Russia.Aim. To evaluate the effect of lumacaftor/ivacaftor therapy on the respiratory function, microbiological profile, nutritional and oxygen status, as well as the rescue antibiotic therapy coverage in adult patients with CF.Materials and methods. 39 adult patients with CF received lumacaftor/ivacaftor for one year. The therapy effectiveness endpoints included the changes in indices of the pulmonary function tests: FEV1, FVC, FEV1/FVC, sweat test results, nutritional and oxygen status, antibiotic therapy coverage. The tolerability of the drug was assessed. The median age of patients was 28.9 (11.3) years. 6 patients (15.4%) discontinued therapy due to different adverse reactions.Results. The median increase in FVC was 2.9 (4.1)%, in FEV1 – 3.1 (4.1)%, sweat chloride decreased by 21 (27) mmol/l during 1–1.5-month lumacaftor/ivacaftor therapy. After 12-month therapy, the median increase in FVC was 2.3 (3.6)%, in FEV1 – 2.4 (3.8)%, BMI increased by 0.6 (0.6) kg/m2 and the frequency of rescue antibiotic therapy decreased by half. The patients showed a significant increase in FVC and FEV1 indices and a decrease in sweat chloride after 1-month therapy and an increase in FEV1 indices, BMI vales as well as a reduced need for rescue antibiotic therapy after 12-month therapy.Conclusion. The first experience with a long-term pathogenetic therapy with lumacaftor/ivacaftor in adult patients with CF in Russia demonstrated the expected positive effect on the respiratory function and changes in nutritional status, a reduced need for rescue antibiotic therapy, and low rates of adverse reactions.

Pengujian Peluahan Sebagian Menggunakan Rogowski Coil Inti Ferit dan Non Ferit dengan Variaasi Lilitan Sebanyak 10 Lilitan

Partial Discharge is one of the phenomena that occurs in the electric power system, which is characterized by the phenomenon of heat which will disrupt the insulation system. If this phenomenon is left for a long time, it will disrupt the process of distributing electricity, even stopping the process of distributing electricity. Partial discharge testing can be tested in 2 ways, namely conventional using coupling and conventional using electromagnetic methods, optical methods, acoustic methods, and chemical methods. Moisture testing in part in this study uses a non-conventional method with the electromagnetic method. The electromagnetic method used is the Rogowski Coil with ferrite and non-ferrite cores. Each Rogowski Coil core has an inner diameter of 1.2 cm, an outer diameter of 2.5 cm, a height of 2.5 cm and a total of 10 turns. The results of the partial sweat test show that the non-ferrite core Rogowski Coil responds faster than the ferrite core Rogowski Coil. As for the sensitivity level of the second core used for partial discharge testing, it can be seen that the Rogowski Coil with a ferrite core is more sensitive than the non-ferrite core with a sensitivity value of 11.63%.

Problems and achievements in the study of clinical and genetic aspects of cystic fibrosis

Cystic fibrosis is a common hereditary autosomal recessive disease characterized by pronounced genetic heterogeneity, associated clinical polymorphism, severe course and prognosis. The disease occurs worldwide in representatives of various populations and ethnic groups, with equal frequency among the male and female population. The molecular pathogenesis of the disease is based on disturbances in the synthesis, structure and function of the cystic fibrosis transmembrane conductance regulator protein (CFTR), which leads to various functional disorders in the work of chloride channels. As a result, the viscosity of secretions increases and exocrinopathy develops, which leads to disruption in the functioning of all organs and systems. The main cause of cystic fibrosis is a mutation in the CFTR gene. There are seven genetic classes of mutations in the CFTR gene, they mainly determine the severity of the disease. The main criterion in the diagnosis of cystic fibrosis is an increase in the concentration of chlorine ions in the secretion of sweat glandsof more than 60mmol/l when performing a sweat test using the classical GibsonCook method. An exception is a mutation in the CFTR 3849+10kbCT gene, which is associated with anormal or borderline sweat test result. For a long time, the treatment of patients suffering from cystic fibrosis was symptomatic, while the course of the disease remained severe and led to early mortality of patients. However, in recent decades, modern achievements in the field of studying the molecular genetic aspects of cystic fibrosis have made it possible to make a scientific breakthrough in the creation of pathogenetic therapy for this disease. New effective drugs that improve the health of patients and their quality of life have appeared. The relevance of studying the molecular mechanism of the disease for the development of a personalized approach in the treatment of cystic fibrosis is increasing, which is a promising direction on the way to gaining health for this category of patients.

Two Years of Newborn Screening for Cystic Fibrosis in North Macedonia: First Experience.

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).

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

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.

Uncommon clinical presentation of cystic fibrosis in a patient homozygous for a rare CFTR mutation: a case report

BackgroundCystic fibrosis (CF) is the most common, life-threatening, autosomal-recessive disorder among Caucasians. To date, approximately 2000 mutations in the CFTR gene have been reported. Some of these mutations are very rare, and some represent individual sequence changes in the gene. The introduction of newborn screening (NBS) in high prevalence countries for CF has considerably changed the diagnosing of this metabolic disease. Currently, in most cases, a diagnosis is made based on NBS, including or expanded with DNA analysis and confirmed with sweat chloride tests, rather than waiting until the child has already developed signs and symptoms. However, in rare cases, NBS does not provide enough information to confirm or reject a CF diagnosis. Not only are there small groups of patients who have false-negative or false-positive NBS results, but there is also a growing number of patients with positive NBS results in whom results of sweat tests and genetic examinations do not provide definite conclusions. Despite all knowledge and modern diagnostic tools at our disposal, sometimes the clinical presentation is so inconclusive, that making a final diagnosis remains a challenge.Case presentationIn this case report, we present a male infant of Polish origin, whose symptoms and laboratory findings (including metabolic acidosis) were strongly suggestive of metabolic disease other than cystic fibrosis. Newborn screening for CF was positive, but the first sweat test results were equivocal, and initial and extended molecular tests were negative. Finally, after considering broad differential diagnosis, introducing treatment specific for CF and excluding other metabolic diseases, a third expanded genetic test revealed the presence of a rare pathogenic mutation in both alleles of the CFTR gene: c.4035_4038dupCCTA (p.Ser1347ProfsX13).ConclusionAlthough CF is considered a monogenic disorder, the relationship between genotype and phenotype is very complex. The reported case shows the unusual presentation of the disease. The patient’s clinical symptoms and laboratory findings, in combination with molecular test results, provide useful information for further observing the genotype-phenotype correlations in cystic fibrosis.

The location and characteristics of the thermal sudomotor pathways in the human brainstem: A reappraisal.

To elucidate location and characteristics of the central thermoregulatory sudomotor pathway in the human brainstem, thermoregulatory sweating (TS) in 91 patients with focal brainstem lesions was studied. TS was symmetric or minimally asymmetric in 40 subjects (Group S), and was apparently asymmetric in 51 patients (Group AS). In Group AS, the main abnormality was ipsilateral segmental hypohidrosis with a varying extent, involving predominantly the upper half of the body. Lesion locations, correlations between thermoregulatory sweat test results, and other autonomic and somatic functions were compared between the groups. The results suggested following: (1) The hypothalamospinal pathway related to TS may pass through the posterior hypothalamus and descend in the dorsolateral part of the brainstem, near the spinal trigeminal and spinothalamic tracts; (2) the pathway may descend together with those related to oculosympathetic and vasoconstrictor systems, but each of these may form distinct fiber groups; (3) the majority of the central TS fibers may reach ipsilateral sudomotor sympathetic neurons of the spinal cord, even though some fibers may cross at various levels; (4) in this descending pathway, somatotopic arrangements corresponding to each of the spinal sympathetic segments must be present; (5) There may be another fiber group passing through the central to dorsal paramedian portions of the brainstem, and lesions of these fibers also result in asymmetric TS, but seldom in oculosympathetic dysfunction. This second pathway probably exerts contralateral inhibitory influence on TS, but its origin, intracerebral course and exact physiological function require further clinical investigations.

Comparison of two sweat test systems for the diagnosis of cystic fibrosis in newborns.

In the national newborn screening programme for CF in Switzerland, we compared the performance of two sweat test methods, by investigating the feasibility and diagnostic performance of the Macroduct® collection method (with chloride mesurement) and Nanoduct® test (measuring conductivity) for diagnosing CF. We included all newborns with a positive screening result between 2011 and 2015 who were referred to a CF-centre for sweat testing. In the CF-centre, a Macroduct and Nanoduct sweat test were performed simultaneously. If sweat test results were positive or borderline, a DNA analysis was performed. Final diagnosis was based on genetic mutations. Over 5 years, 445 children were screened positive and in 413 (114 with CF) at least one sweat test was performed (median age at first test, 22 days); both tests were performed in 371 children. A sweat test result was more often available with the Nanoduct compared to the Macroduct (79 vs 60%, P < 0.001). The Nanoduct was equally sensitive as the Macroduct in identifying newborns with CF (sensitivity 98 vs 99%) but less specific (specificity 79 vs 93%; P-value comparing ROC curves = 0.033). This national multicentre study revealed high failure rates for Macroduct and Nanoduct in newborns in real life practice. While this needs to be addressed, our results suggested that performing the Nanoduct in addition to the Macroduct might speed up the diagnostic process because it more often yields valid results with comparable diagnostic performance. The addition of the Nanoduct sweat test can therefore help to reduce the stressful time of uncertainty for parents and to start appropriate treatment earlier.

Initial regional evaluation of the Cystic Fibrosis Newborn Screening Program: data from the Mediterranean coast of Turkey

Background/ aimSince January 2015, the Cystic Fibrosis Newborn Screening (CFNS) program has been implemented in Turkey. We aimed to evaluate the demographic, clinical, and laboratory data of cases referred from the CFNS program and to determine the most suitable cut-off value for immunoreactive trypsinogen (IRT)-1 and immunoreactive trypsinogen (IRT-2) that are used in the CFNS program in Turkey.Materials and methodsA total of 156 Turkish Caucasian subjects were determined as positive cases during 3 years, from January 2015 to January 2018, and were referred to the pediatric pulmonology clinics of Akdeniz University Hospital, Antalya, Turkey, for the national CFNS program. The evaluation was made considering the IRT-1 and IRT-2 values, demographic characteristics, sweat test results, CFTR genotypes, and diagnoses.ResultsNine patients were diagnosed with cystic fibrosis (CF). Eight were diagnosed with CF-related metabolic syndromes and three were determined to be CF carriers. The ratio of CF to CF-related metabolic syndrome was determined as 1.1:1. Considering the limits of the present CFNS program and the IRT method, the positive predictive value (PPV) for the referred cases was determined as 5.8%. When a cut-off value of 105.6 ng/mL was taken for IRT-1, sensitivity was 100%, specificity was 59%, and PPV was 12.8%. For a cut-off value of 88.75 ng/mL for IRT-2, sensitivity was determined as 90%, specificity as 65%, and PPV as 15.2%.ConclusionThis is the first detailed clinical study to evaluate the data from the CFNS program along the Mediterranean coast of Turkey. As false positive results are extremely high in Turkey, there is an urgent need for revision of the IRT-1 and IRT-2 limits by evaluating the data of the whole country.

Spirometric caracterization of cystic fibrosis patients

The prognosis of patients with cystic fibrosis (CF) has remarkably improved. The as sessment of the disease progression is based on the measurement of the FEV1 (Forced Expiratory Volume in one second). 1. To describe forced expiratory flows and volumes and com pare their interpretation according to different reference standards (Knudson, Gutiérrez, and multi ethnic GLI); 2. To describe bronchodilator response. The medical records and spirometries of all patients with CF controlled at the Dr. Sotero del Rio Hospital were reviewed. Demographic background, sweat test results, genetic study , and bacteriological study were obtained. In addition, Forced Vital Capacity (FVC) was recorded as well as FEV1 and FEV1/FVC ratio. Re sults: Data from 14 patients, were analyzed, seven males, aged 6-24 years, median 15 years, median BMI 18.15 (range 14.6-23.3), median sweat chloride test 76 mEq/l (range 50,2-119 mEq/l), seven patients with at least one F508del mutation. Using multi-ethnic and Gutierrez predictive formulas, lung function involvement occurred previously in relation to the use of Knudson equations. None of the patients had a significant bronchodilator response. The group of patients descri bed mostly presents functional respiratory involvement and had no bronchodilator response. The interpretation of functional respiratory involvement varies according to the theoretical values used.

Optimization of the French cystic fibrosis newborn screening programme by a centralized tracking process.

ObjectivesTo evaluate the French cystic fibrosis newborn screening algorithm, based on data tracked by a centralized monitoring process, from 2002 to 2014. The programme aimed to attain European Standards in terms of positive predictive value, sensitivity, the ratio of screen positive patients diagnosed with cystic fibrosis to infants who screen positive but with inconclusive diagnosis (CFSPID), and time to diagnosis.MethodsRetrospective analysis of programme performance, compliance with the algorithm, and changes in screening strategy.ResultsModifications in the flow chart protocol improved the positive predictive value to 0.31 while maintaining the sensitivity at 0.95. Among infants diagnosed with cystic fibrosis, or identified as CFSPID, sweat test results were obtained for 94%, and two mutations were identified after exhaustive screening for the gene, when applicable, in 99.6%. The rate of pending diagnosis was very low (0.5%). The ratio of infants with cystic fibrosis:CFSPID was 6.3:1. Age at initial visit at the CF centre was ≤ 35 days, respectively, in 53%/26%.ConclusionPerformances were in agreement with European standards, but timeliness of initial visit needed improvement. Our data complement an accumulating body of evidence demonstrating that attention must be paid to such ethical considerations as limiting carrier detection and inconclusive diagnosis. Newborn screening programmes should have a rigorous centralized monitoring process to warrant adjustments for improving performance to attain consensus guidelines.

Biological Variation of Chloride and Sodium in Sweat Obtained by Pilocarpine Iontophoresis in Adults: How Sure are You About Sweat Test Results?

The measurement of chloride and sodium concentrations in sweat is an important test for the diagnosis of cystic fibrosis (CF). The aim of this study was to assess the analytical variation (CVA) and within-subject (CVI) and between-subject (CVG) biological variation of chloride and sodium concentrations in sweat, collected by pilocarpine iontophoresis and to determine their effect on the clinical interpretation of sweat test results. Twelve Caucasian adults (six male and six female) without symptoms suggestive for CF and with a mean age of 41years (range 28-59) were included in the study. At least eight samples of sweat were collected from each individual by pilocarpine iontophoresis. Chloride and sodium concentrations were measured in duplicate for each sample using ion selective electrodes. After the removal of outliers, the CVA, CVI, and CVG of chloride and sodium were determined, and their impact on measurement uncertainty and reference change value were calculated. The CVA, CVI, and CVG of chloride in sweat samples were 6.5, 17.7, and 47.2%, respectively. The CVA, CVI, and CVG of sodium sweat samples were 6.0, 17.5, and 42.6%, respectively. Our study indicates that sweat chloride and sodium concentration results must be interpreted with great care. Different components of variation, particularly the biological variations, have a considerable impact on the interpretation of these results. If no pre-analytical, analytical, or post-analytical errors are suspected, repeated sweat testing to confirm first-measurement results might not be desirable.

Epidermal Nerve Fiber Quantification in Patients With Erythromelalgia

Erythromelalgia is a clinical diagnosis based on intermittent warmth, erythema, and pain in the distal extremities. One problem facing physicians is how to objectively test for this disease. Given that other painful conditions of the distal extremities (ie, neuropathy related to human immunodeficiency virus, diabetes, or Fabry disease) can be evaluated with a skin biopsy to visualize pathologically decreased densities of the small nerve fibers that innervate the epidermis, one hypothesis is that erythromelalgia could similarly be associated with a loss of epidermal nerve fiber density (ENFD). To examine whether erythromelalgia is associated with a structural loss of small fibers using the ENFD technique and to compare this with functional studies of small nerve fibers. In a retrospective study of 52 consecutive patients with erythromelalgia who were seen between September 1, 2010, and September 22, 2015, patients were interviewed and examined and their conditions clinically diagnosed by a board-certified dermatologist at a large tertiary referral center, where ENFD testing became a routine part of evaluating erythromelalgia in 2010. Thus, all 52 consecutive patients were included solely based on their clinical diagnosis of erythromelalgia. For quantification of ENFD, observers were masked to all patient information except for name and clinic number. The hypothesis that patients with erythromelalgia would have decreased ENFD was formulated before data collection. Epidermal nerve fiber density, the primary outcome, is a measurement of the density of small nerve fibers within the epidermis. Secondary measures included functional small fiber evaluation, such as autonomic (heart rate, blood pressure, and sweat testing) and subjective testing of pain. In this cohort study, 52 consecutively seen patients were identified (female, 42 [80%]; median age, 44 years; age range, 13-82 years). Whereas only 5 of 52 patients (10%) had ENFD at or below the fifth percentile of healthy control individuals, most patients had functional abnormalities of these small fibers; 29 patients (60%) had abnormal sweat test results, 21 (42%) had abnormal pain thresholds, and 20 (38%) had abnormal blood pressure or heart rate control. Unlike other diseases of the small nerve fibers that cause acral pain syndromes, erythromelalgia is not characterized by loss of ENFD. However, most patients have impaired function of these small fibers. Physicians would benefit from performing functional rather than structural small fiber studies when evaluating erythromelalgia.

WS20.2 Intra-patient variability of sweat chloride concentrations in patients with cystic fibrosis (CF)

Introduction Sweat chloride concentration, a biomarker of CFTR function, is an appropriate outcome parameter in clinical trials aimed at correcting the basic CF defect. Although we agree on a cut-of value to diagnose CF, we have only limited information on the natural variability of sweat chloride over time. Still, this information is useful for power calculations in clinical trials. Therefore, we analyzed sweat test results obtained in patients with G551D mutation(s) assigned to placebo in an ivacaftor interventional trial. Methods In subjects with G551D at least 12 years of age, a pilocarpine sweat test using Macroduct collector was taken on both arms at 8 time points over 48 weeks. We explored 1062 pilocarpine sweat test values obtained in 78 patients. Results Mean overall sweat chloride value (all patients, all tests) was 100.1 mmol/L (95% CI 96.4–103.7). Using a random coefficient model, the within-subject standard deviation(SD) for sweat chloride was 8.5 mmol/L (95% CI 8.1–8.9) and between-subject SD was 9.8 mmol/L (95% CI 8.1–11.9). Standard deviations were similar with results from the left and from the right arm. Taking the mean measure of both arms rather than the result of one arm decreased within-subject SD by only 0.3 mmol/L. Conclusion Although the sweat test is considered a robust measure, sweat chloride measurements in patients with CF had an inherent biological variability that is higher than commonly considered. Further analyses of placebo arm data are crucial to learn more about the natural variability of outcome parameters.