Rate and predictors of insufficient sweat volume in very young infants after pilocarpine gel iontophoresis: prospective, population-based study.

OBJECTIVE: To verify the rate and predictors of 'quantity not sufficient' (QNS) among Brazilian infants younger than 3 months with positive newborn screening (NBS) for cystic fibrosis (CF). DESIGN: Prospective, population-based study. SETTING: Public Statewide Newborn Screening Programme where the incidence rate of CF is ≈1:11 000. PATIENTS: Subjects with positive two-tiered immunoreactive trypsinogen. INTERVENTIONS: Sweat induction and collection were performed in the same facility; one sweat sample was obtained per individual. MAIN OUTCOME MEASURES: The QNS rate and its predictors; analysis corresponded to the day of sweat collection. RESULTS: Among the 975 participants, QNS rates for 10 and 15 µL were 3.6% (95% CI 2.5% to 4.9%) and 8.3% (95% CI 6.6% to 10.2%). Infants weighing >3056 and >3845 g and with gestational age higher than 37 weeks had a greater likelihood (5.5 and 6.7, and 2.7 and 5.8 times more, respectively) of avoiding QNS than their peers. CONCLUSION: QNS rates fulfilled the requirements, but predictors differed from those recommended by the Cystic Fibrosis Foundations guidelines.

Sweat conductivity for diagnosing cystic fibrosis after positive newborn screening: prospective, diagnostic test accuracy study.

OBJECTIVE: To assess the accuracy of sweat conductivity among newborns and very young infants. DESIGN: Prospective, population-based, diagnostic test accuracy study. SETTING: Public Statewide Newborn Screening Programme where the incidence rate of cystic fibrosis (CF) is ≈1:11 000. PATIENTS: Newborns and very young infants with positive two-tiered immunoreactive trypsinogen. INTERVENTIONS: Sweat conductivity and sweat chloride were performed simultaneously, on the same day and facility by independent technicians, with the cut-off values of 80 mmol/L and 60 mmol/L, respectively. MAIN OUTCOME MEASURES: Sensitivity, specificity, positive and negative predictive values (PPV and NPV), overall accuracy, positive and negative likelihood ratios (+LR, -LR) and post (sweat conductivity (SC)) test probability were calculated to assess SC performance. RESULTS: 1193 participants were included, 68 with and 1108 without CF, and 17 with intermediate values. The mean (SD) age was 48 (19.2) days, ranging from 15 to 90 days. SC yielded sensitivity of 98.5% (95% CI 95.7 to 100), specificity of 99.9% (95% CI 99.7 to 100), PPV of 98.5% (95% CI 95.7 to 100) and NPV of 99.9% (95% CI 99.7 to 100), overall accuracy of 99.8% (95% CI 99.6 to 100), +LR of 1091.7 (95% CI 153.8 to 7744.9) and -LR of 0.01 (95% CI 0.00 to 0.10). After a positive and negative sweat conductivity result, the patient's probability of CF increases around 350 times and drops to virtually zero, respectively. CONCLUSION: Sweat conductivity had excellent accuracy in ruling in or ruling out CF after positive two-tiered immunoreactive trypsinogen among newborns and very young infants.

Five-year performance analysis of a cystic fibrosis newborn screening program in northeastern Brazil.

OBJECTIVE: To analyze the performance of the cystic fibrosis (CF) newborn screening (NBS) program over its first five years in a Brazilian northeastern state. METHOD: A population-based study using a screening algorithm based on immunoreactive trypsinogen (IRT)/IRT. Data were retrieved from the state referral screening center registry. The program performance was evaluated using descriptive indicators such as the results of an active search, coverage, newborn's age at the time of blood sampling, the time between sample collection and its arrival at the laboratory, and the child's age at diagnosis of disease. RESULTS: The public CF screening program covered 82.6% of the 1,017,576 births that occurred, with an accumulated five-year incidence of 1:20,767 live births. The median (25th-75th) age at diagnosis was 3.5 (2.3-7.3) months. The sampling before 7 days of life for the first IRT (IRT1) increased between 2013 and 2017 from 42.2 to 48.3%. Around 5% of IRT1 samples and 30% of the second samples were collected after 30 days of life. In the first and second stages of screening, 23.6% and 19.9% of the infants, respectively, were lost to follow-up. In both stages of screening, the samples were retained at the health units for a median (25th-75th) of 9.0 (7.0-13.0) days. CONCLUSIONS: The coverage by the CF-NBS program was satisfactory as compared to other Brazilian state rates and the percentage of IRT1 samples collected within the first week of life increased progressively. However, time of samples retention at the health units, inappropriate sampling, inherent methodological problems, and loss of follow-up need to improve.

Comparison between two newborn screening strategies for cystic fibrosis in Argentina: IRT/IRT versus IRT/PAP.

BACKGROUND: The benefits of early cystic fibrosis (CF) detection using newborn screening (NBS) has led to widespread use in NBS programs. Since 2002, a two-stage immunoreactive trypsinogen (IRT/IRT) screening strategy has been used as a CFNBS method in all public maternity units in the City of Buenos Aires, Argentina. However, novel screening strategies may be more efficient. The aim of this study is to prospectively compare two CFNBS strategies: IRT/IRT and IRT/PAP (pancreatitis-associated protein). METHODS: A two-year prospective study was performed. IRT was measured in dried blood samples collected 48-72 h after birth. When an IRT value was abnormal, PAP was determined, and a second visit was scheduled to obtain another sample for IRT before 25 days of life. Newborns with a positive CFNBS were referred for a confirmatory sweat test. RESULTS: There were 69,827 births in the City of Buenos Aires during the period studied; 918 (1.31%) had an abnormal IRT. A total of 207 children (22.5%) failed to return for the second IRT, but only two PAP (0.2%) were not performed. IRT/IRT was more likely to lead to a referral for sweat testing than IRT/PAP (odds ratio 2.3 [95% confidence interval 1.8-2.9], p < .001). Sensitivity and specificity were: 80% and 100% and 86.5% and 82.6% for IRT/IRT and IRT/PAP strategies, respectively. CONCLUSION: The IRT/PAP strategy is more sensitive than IRT/IRT and has similar specificity; it avoids a second visit and unnecessary sweat testing, and it reduces loss to follow-up in our population.

The first five-year evaluation of cystic fibrosis neonatal screening program in São Paulo State, Brazil.

The Hospital of the Ribeirão Preto Medical School, University of São Paulo is one of the three screening centers in São Paulo State, Brazil, and has included a test for cystic fibrosis (CF) since February 6, 2010, by a court order. We evaluated the first five years of this CF-newborn screening program. The original immunoreactive trypsinogen (IRT)/IRT screening protocol was adopted in Brazil. A total of 173,571 newborns were screened, 1,922 (1.1%) of whom showed IRT1 ≥ 70ng/mL. Of these, 1,795 (93.4%) collected IRT2, with elevated results (IRT2 ≥ 70ng/mL) in 102 of them (5.2%). We identified a total of 26 CF cases during this period, including three CF cases that were not detected by the CF-newborn screening. The incidence of the disease among the screened babies was 1:6,675 newborns screened. Median age at the initial evaluation was 42 days, comparable to that of neonates screened with the IRT/DNA protocol. Almost all infants with CF already exhibited some manifestations of the disease during the neonatal period. The mutation most frequently detected in the CF cases was F508del. These findings suggest the early age at the beginning of treatment at our center was due to the effort of the persons involved in the program regarding an effective active search. Considering the false negative results of CF-newborn screening and the early onset of clinical manifestations of the disease in this study, pediatricians should be aware of the diagnosis of CF even in children with negative test.

Pilot study for cystic fibrosis neonatal screening: the Cuban experience.

Background In Cuba, no screening program for cystic fibrosis (CF) has been implemented yet. The ultramicro enzyme-linked immunosorbent assay (UMELISA)® TIR NEONATAL has been developed for the measurement of immunoreactive trypsin (IRT) in dried blood spots on filter paper. The analytical performance of the kit was evaluated in the national network of laboratories. Methods Newborn dried blood samples (DBS) were evaluated in 16 laboratories. An IRT/IRT/DNA protocol was followed using a cut-off value of 50 ng/mL. The mean, median and percentiles of the distribution were calculated and a two-sample t-test with unequal variance was used for statistical analysis. Influence of perinatal factors on IRT levels was analyzed. Results From January to June 2018, 6470 newborns were studied, obtaining a mean IRT value of 12.09 ng/mL (ranging 0-358 ng/mL) and a median of 8.99 ng/mL. Fifty-two samples (0.78%) were above the cut-off level and 16 samples (0.24%) were elevated in the re-screening process. One of them was confirmed positive by molecular biology (phe508del/c.3120 + 1G > A), constituting the first newborn screened and diagnosed early in Cuba. Second DBS samples were collected on average at 14 days and processed in the laboratory at 16 days of birth. Significant differences were observed (p < 0.05) when evaluating the influence of gender, birth weight (BW) and gestational age (GA) on the IRT values. Lower IRT concentrations were found in samples processed after 10 days of collection. Conclusions The performance of UMELISA® TIR NEONATAL in the laboratories has been satisfactory; hence CF newborn screening (NBS) was extended throughout the country from January 2019.

The first five-year evaluation of cystic fibrosis neonatal screening program in São Paulo State, Brazil / Uma avaliação dos primeiros cinco anos do programa de triagem neonatal da fibrose cística no Estado de São Paulo, Brasil / Una evaluación de los primeros cinco años del programa de cribado neonatal de fibrosis cística en el Estado de São Paulo, Brasil

The Hospital of the Ribeirão Preto Medical School, University of São Paulo is one of the three screening centers in São Paulo State, Brazil, and has included a test for cystic fibrosis (CF) since February 6, 2010, by a court order. We evaluated the first five years of this CF-newborn screening program. The original immunoreactive trypsinogen (IRT)/IRT screening protocol was adopted in Brazil. A total of 173,571 newborns were screened, 1,922 (1.1%) of whom showed IRT1 ≥ 70ng/mL. Of these, 1,795 (93.4%) collected IRT2, with elevated results (IRT2 ≥ 70ng/mL) in 102 of them (5.2%). We identified a total of 26 CF cases during this period, including three CF cases that were not detected by the CF-newborn screening. The incidence of the disease among the screened babies was 1:6,675 newborns screened. Median age at the initial evaluation was 42 days, comparable to that of neonates screened with the IRT/DNA protocol. Almost all infants with CF already exhibited some manifestations of the disease during the neonatal period. The mutation most frequently detected in the CF cases was F508del. These findings suggest the early age at the beginning of treatment at our center was due to the effort of the persons involved in the program regarding an effective active search. Considering the false negative results of CF-newborn screening and the early onset of clinical manifestations of the disease in this study, pediatricians should be aware of the diagnosis of CF even in children with negative test.

O Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo é um dos três centros de triagem da fibrose cística (FC) no estado de São Paulo, tendo incluído esse teste desde 6 de fevereiro de 2010, a partir de uma liminar judicial. O estudo avalia os primeiros cinco anos desse programa de triagem neonatal da FC. O Brasil adota o protocolo de triagem original, com o tripsinogênio imunorreativo (IRT)/IRT. Foram triados um total de 173.571 recém-nascidos, dos quais 1.922 (1,1%) mostraram IRT ≥ 70ng/mL. Destes, 1.795 (93,4%) tiveram amostras coletadas para IRT2, com resultados elevados (IRT2 ≥ 70ng/mL) em 102 deles (5,2%). Identificamos um total de 26 casos de FC durante esse período, inclusive 3 casos de FC que não foram detectados com a triagem neonatal. A incidência da FC foi de 1 caso em cada 6.675 recém-nascidos triados. A idade mediana na avaliação inicial foi 42 dias, comparável à idade de recém-nascidos triados com o protocolo IRT/DNA. Quase todos os lactentes com FC já exibiam algumas manifestações da doença durante o período neonatal. A mutação mais comum nos casos de FC foi a F508del. Os resultados em nosso centro indicam que a idade precoce no início do tratamento foi devido aos esforços do programa na implementação de uma busca ativa eficaz. Considerando os resultados falsos-negativos no programa de triagem neonatal para FC e o início precoce das manifestações clínicas da doença neste estudo, os pediatras devem estar cientes da possibilidade de diagnóstico de FC, mesmo em crianças com teste negativo.

El Hospital das Clínicas de la Facultad de Medicina de Ribeirão Preto, São Paulo Universidad es uno de los tres centros de cribado de fibrosis cística (FC) en el estado de São Paulo, incluyendo este test desde el 6 de febrero de 2010, debido a una medida cautelar judicial. El estudio evalúa los primeros cinco años de este programa de cribado neonatal de FC. Brasil adopta el protocolo de cribado original, con el tripsinógeno inmunorreactivo (TIR)/IRT. Se cribaron un total de 173.571 recién nacidos, de los cuales 1.922 (1,1%) mostraron IRT ≥ 70ng/mL. De estos, se obtuvieron 1.795 (93,4%) muestras recogidas para IRT2, con resultados elevados (IRT2 ≥ 70ng/mL) en 102 de ellos (5,2%). Identificamos un total de 26 casos de FC durante ese período, inclusive 3 casos de FC que no fueron detectados con el cribado neonatal. La incidencia de la FC fue de 1 caso por cada 6.675 recién-nacidos cribados. La edad media en la evaluación inicial fue 42 días, comparable a la edad de recién nacidos cribados con el protocolo IRT/DNA. Casi todos los lactantes con FC ya manifestaban algunos síntomas de la enfermedad durante el período neonatal. La mutación más común en los casos de FC era el F508del. Los resultados en nuestro centro indican que la edad precoz en el inicio del tratamiento se debía a los esfuerzos del programa en la implementación de una búsqueda activa eficaz. Considerando los resultados falsos-negativos en el programa de cribado neonatal para FC, y el inicio precoz de las manifestaciones clínicas de la enfermedad en este estudio, los pediatras deben ser conscientes de la posibilidad de diagnóstico de FC, incluso en niños con test negativo.

Secondhand Smoke Exposure and Serum Trypsinogen in Cystic Fibrosis Carriers.

OBJECTIVE: The objective of this study was to determine if infants carrying 1 cystic fibrosis transmembrane receptor (CFTR) mutation demonstrate pancreatic inflammation in response to tobacco exposure. METHODS: Cystic fibrosis carrier infants aged 4 to 16 weeks were prospectively enrolled. Tobacco exposure was assessed by survey and maternal hair nicotine analysis. Serum immunoreactive trypsinogen (IRT) levels at birth and at the time of recruitment were analyzed relative to the presence or absence of tobacco exposure. The effect of the severity of the CFTR mutation carried by the infant on the tobacco-IRT relationship was also analyzed. RESULTS: Forty-eight infants completed the study. Newborn screen and follow-up IRT levels were not different between exposed infants (19 by hair analysis) and nonexposed infants (29 by hair analysis). Follow-up IRT levels were lower in infants with more severe CFTR mutations (P = 0.005). There was no difference in follow-up IRT based on CFTR mutation severity in exposed infants. Nonexposed infants with milder CFTR mutations had higher median IRT values on follow-up testing than those with more severe CFTR mutations (P < 0.05). CONCLUSIONS: The pancreas of cystic fibrosis carrier infants is affected by tobacco exposure, and those carrying less severe CFTR mutations may be more susceptible to tobacco effects.

Biochemical characterization of recombinant Penaeus vannamei trypsinogen.

Trypsinogens are the inactive precursors of trypsins (EC 3.4.21.4), which are digestive serine proteases. Despite knowing the properties of trypsins from Pacific white shrimp, Penaeus vannamei, the biochemical properties of shrimp trypsinogens including activation mechanisms and kinetics are unknown, due to difficulties isolating them from natural sources. In the present work, we describe the purification and biochemical characterization of four trypsinogen-like isoforms from recombinant P. vannamei trypsinogen, with a special emphasis on understanding its activation kinetics. The major trypsinogen-like isoform had an apparent molecular mass of 29 kDa. The other three forms of recombinant trypsinogen were: an N-glycosylated form of 32 kDa, a possibly O-glycosylated form of 41 kDa, and a likely double-chain form with a subunit of 23 kDa. The autoactivation profile of three-recombinant trypsinogen-like isoforms showed increased trypsin activity at a rate that was higher than that of bovine trypsinogen. This confirms the hypothesis proposed in the literature of a rapid trypsinogen autoactivation in the absence of aspartates in the activation peptide as it is for P. vannamei trypsinogen.

An Enzyme Immunoassay for Determining Immunoreactive Trypsinogen (IRT) in Dried Blood Spots on Filter Paper Using an Ultra-Microanalytical System.

Cystic fibrosis (CF) is a severe autosomal recessive disorder. It is caused by mutations in the CF transmembrane conductance regulator gene. Early diagnosis of CF can be carried out by determining high immunoreactive trypsinogen (IRT) blood values in newborns. A simple sandwich-type ultramicroELISA assay (UMELISA®) has been developed for the measurement of IRT in dried blood spots on filter paper. Strips coated with a high affinity monoclonal antibody directed against IRT are used as solid phase, to ensure the specificity of the assay. The assay is carried out within 20 h. The useful rank of the curve is 0-500 ng/mL, and the lowest detectable concentration is 4.8 ng/mL. Intra- and inter-assay coefficients of variation were lower than 10%. The recovery mean value was 100.3 ± 11.2%. Cross-reactivity with proteins structurally related to IRT (α2-macroglobulin, α1-antitrypsin, and human chymotrypsin) was lower than the detection limit of the assay. Four thousand four hundred six newborn samples from the Cuban Newborn Screening Program were analyzed, and the mean IRT concentration was 12.8 ng/mL. Higher IRT values were obtained when samples were eluted overnight. Regression analysis showed a good correlation with the commercially available AutoDELFIA® Neonatal IRT kit (n = 3948, r = 0.885, ƙ = 0.976, p < 0.01). The analytical performance characteristics of our UMELISA® TIR Neonatal suggest that it can be used for the neonatal screening of CF.

Newborn cystic fibrosis screening in southeastern Mexico: Birth prevalence and novel CFTR gene variants.

OBJECTIVE: To use the results of the first five years of a cystic fibrosis newborn screening program to estimate the cystic fibrosis birth prevalence and spectrum of cystic fibrosis transmembrane conductance regulator ( CFTR) gene variants in Yucatan, Mexico. METHODS: Screening was performed from 2010 to 2015, using two-tier immunoreactive trypsinogen testing, followed by a sweat test. When sweat test values were >30 mmol/L, the CFTR gene was analyzed. RESULTS: Of 96,071 newborns screened, a second sample was requested in 119 cases. A sweat test was performed in 30 newborns, and 9 possible cases were detected (seven confirmed cystic fibrosis and two inconclusive). The most frequently detected CFTR pathogenic variant (5/14 cystic fibrosis alleles, 35.7%) was p.(Phe508del); novel p.(Ala559Pro) and p.(Thr1299Hisfs*29) pathogenic variants were found. CONCLUSIONS: Cystic fibrosis birth prevalence in southeastern Mexico is 1:13,724 newborns. Immunoreactive trypsinogen blood concentration is influenced by gestational age and by the time of sampling. The spectrum of CFTR gene variants in Yucatan is heterogeneous.

Both Exocrine Pancreatic Insufficiency and Signs of Pancreatic Inflammation Are Prevalent in Children with Complicated Severe Acute Malnutrition: An Observational Study.

OBJECTIVES: To assess whether pancreatic function is impaired in children with severe acute malnutrition, is different between edematous vs nonedematous malnutrition, and improves by nutritional rehabilitation. STUDY DESIGN: We followed 89 children with severe acute malnutrition admitted to Queen Elizabeth Central Hospital in Blantyre, Malawi. Stool and blood samples were taken on admission and 3 days after initial stabilization to determine exocrine pancreatic function via fecal elastase-1 (FE-1) and serum trypsinogen and amylase levels. RESULTS: A total of 33 children (37.1%) had nonedematous severe acute malnutrition, whereas 56 (62.9%) had edematous severe acute malnutrition. On admission, 92% of patients showed evidence of pancreatic insufficiency as measured by FE-1 <200 µg/g of stool. Patients with edematous severe acute malnutrition were more likely to have low FE-1 (98% vs 82.8%, P = .026). FE-1 levels remained low in these individuals throughout the assessment period. Serum trypsinogen was elevated (>57 ng/mL) in 28% and amylase in 21% (>110 U/L) of children, suggesting pancreatic inflammation. CONCLUSION: Exocrine pancreatic insufficiency is prevalent in children with severe acute malnutrition and especially in children with edematous severe acute malnutrition. In addition, biochemical signs suggestive of pancreatitis are common in children with severe acute malnutrition. These results have implications for standard rehabilitation treatment of children with severe acute malnutrition who may benefit from pancreatic enzyme replacement therapy. TRIAL REGISTRATION: ISRCTN.com: 13916953.

Improving the Sensitivity and Positive Predictive Value in a Cystic Fibrosis Newborn Screening Program Using a Repeat Immunoreactive Trypsinogen and Genetic Analysis.

OBJECTIVE: To evaluate the performance of a new cystic fibrosis (CF) newborn screening algorithm, comprised of immunoreactive trypsinogen (IRT) in first (24-48 hours of life) and second (7-14 days of life) dried blood spot plus DNA on second dried blood spot, over existing algorithms. STUDY DESIGN: A retrospective review of the IRT/IRT/DNA algorithm implemented in Colorado, Wyoming, and Texas. RESULTS: A total of 1 520 079 newborns were screened, 32 557 (2.1%) had abnormal first IRT; 8794 (0.54%) on second. Furthermore, 14 653 mutation analyses were performed; 1391 newborns were referred for diagnostic testing; 274 newborns were diagnosed; and 201/274 (73%) of newborns had 2 mutations on the newborn screening CFTR panel. Sensitivity was 96.2%, compared with sensitivity of 76.1% observed with IRT/IRT (105 ng/mL cut-offs, P < .0001). The ratio of newborns with CF to heterozygote carriers was 1:2.5, and newborns with CF to newborns with CFTR-related metabolic syndrome was 10.8:1. The overall positive predictive value was 20%. The median age of diagnosis was 28, 30, and 39.5 days in the 3 states. CONCLUSIONS: IRT/IRT/DNA is more sensitive than IRT/IRT because of lower cut-offs (∼97 percentile or 60 ng/mL); higher cut-offs in IRT/IRT programs (>99 percentile, 105 ng/mL) would not achieve sufficient sensitivity. Carrier identification and identification of newborns with CFTR-related metabolic syndrome is less common in IRT/IRT/DNA compared with IRT/DNA. The time to diagnosis is nominally longer, but diagnosis can be achieved in the neonatal period and opportunities to further improve timeliness have been enacted. IRT/IRT/DNA algorithm should be considered by programs with 2 routine screens.

Ontogeny changes and weaning effects in gene expression patterns of digestive enzymes and regulatory digestive factors in spotted rose snapper (Lutjanus guttatus) larvae.

The study of digestive physiology is an important issue in species that have been introduced in aquaculture like the spotted rose snapper (Lutjanus guttatus). The aims of this study were to describe the expression of digestive enzymes (trypsinogen, chymotrypsinogen, α-amylase, lipoprotein lipase, phospholipase A and pepsinogen) and their relation with orexigenic (neuropeptide Y, NPY) and anorexigenic (cholecystokinin, CCK) factors during the larval development and to evaluate the effect of weaning in their expression. The results showed that the transcripts of all the assayed digestive enzymes, with the exception of pepsinogen, and NPY and CCK were already present in L. guttatus from the hatching stage. The expression of all the enzymes was low during the yolk-sac stage (0-2 days after hatching, DAH), whereas after the onset of exogenous feeding at 2 DAH, their expression increased and fluctuated throughout larval development, which followed a similar pattern as in other marine fish species and reflected changes in different types of food items and the progressive maturation of the digestive system. On the other hand, weaning of L. guttatus larvae from live prey onto a microdiet between 25 and 35 DAH significantly affected the relative expression of most pancreatic digestive enzymes during the first weaning days, whereas chymotrypsinogen 2 and lipoprotein lipase remained stable during this period. At the end of co-feeding, larvae showed similar levels of gene expression regardless of the diet (live prey vs. microdiet), which indicated that larvae of L. guttatus were able to adapt their digestive capacities to the microdiet. In contrast, feeding L. guttatus larvae with live feed or microdiet did not affect the expression of CCK and NPY. The relevance of these findings with regard to current larval rearing procedures of L. guttatus is discussed.

Fibrosis quística y tamizaje neonatal / Newborn screening and cystic fibrosis

Newborn screening for cystic fibrosis is a public health strategy that as been associated with early improved nutrition and survival, and the potential for preventing severe health problems. Various protocols have been employed, being the measurement of immunoreactive trypsynogen (IRT) in the first few days of life the first step in all of them. The second tier can include IRT/IRT, IRT/DNA, IRT/PAP (pancreatitis associated protein). Protocol selection depends on the priorities for each country but at present there is no optimal strategy.

El tamizaje neonatal para fibrosis quística es una estrategia de salud pública que ha demostrado beneficios nutricionales, aumento de la sobrevida y potencialmente prevención de problemas severos de salud. En el mundo se usan variados protocolos, sin embargo en todos el primer paso es la determinación de tripsinógeno inmunorreactivo (IRT) en sangre, tomado del talón del recién nacido. El segundo paso incluye la determinación de un segundo IRT o determinación de DNA o PAP (Proteína asociada a pancreatitis). La selección del protocolo a seguir depende de cada país pero hasta ahora no hay una estrategia óptima.

Pesquisa neonatal en fibrosis quística: un modelo de coordinación multidisciplinaria. ha llegado la hora de los centros de fibrosis quística / Cystic fibrosis screening: amultidisciplinary coordinationapproach. the time for cysticfibrosis centers has arrived

Introducción. La pesquisa neonatal para fibrosis quística ha demostrado su utilidad en el diagnóstico precoz con mejoría en nutrición, función pulmonar y cognición. Se coordinaron dos centros para la medición de los valores de TIR y diagnóstico de fibrosis quística, usando un algoritmo tradicional y uno adaptado para mejorar resultados previos sin coordinación. Método. Se presentan datos del período pre-coordinación donde no hubo diagnósticos de FQ a partir de TIR. Se detallan datos del período coordinado, que aun no siendo cronológica ni numéricamente igual al anterior, muestran resultados totalmente distintos. Para TIR se utilizó DELFIA y para test de sudor iontoforesis por pilocarpina. Resultados. Período pre-coordinación entre centros (enero de 2005 a febrero de 2010): se realizaron 18.732 determinaciones de TIR. 74 fueron TIR (+). No hubo diagnósticos de FQ por problemas de seguimiento. Período coordinado: desde el 1° de marzo de 2010 hasta el 31 de diciembre de 2011. Se realizaron 41.142 determinaciones de TIR. Se encontró TIR elevado en la 1ª muestra en 91 niños (0,22%). Se diagnosticaron 4 fibroquísticos por medio de los algoritmos presentados. Conclusiones. En 71 RN seguidos efectivamente con TIR positivo, se diagnosticaron 4 FQ en el período coordinado. Disminuyó la edad media al diagnóstico de 4,54 años a 2,5 meses (aún pocos casos) y la cantidad de perdidos al seguimiento bajó de 36,95 % a 15,90%. Estas cifras sugieren un resultado positivo producto de la integración y centralización de los sistemas como lo cita toda la literatura.

Introduction. Neonatal screening in cystic fibrosis has shown to be an important tool for early diagnosis, better nutrition, diminished lung function and cognitive development. Our laboratory and CF Center were coordinated for IRT screening and diagnosis. We used a standard and a modified algorithm to improve previous results of an uncoordinated period. Method. IRT-IRT-sweat test algorithms was implemented using Dissociation-Enhanced Lanthanide Fluroimmunoassay (DELFIA) for IRT, and pilocarpine iontophoresis for sweat test. Pre-coordination period data are also presented (January 2005 - February 2010) when follow up was difficult .Details for the coordinated period are presented although no statistical comparisons are intended since the number of patients and time-periods studied were completely different. Results. a) pre-coordination period: 18,732 IRT measurements were done. 74 positive IRT tests were detected. No CF diagnosis was made by IRT screening due to problems with follow-up. Only 3 CF patients were diagnosed by genetic studies requested only due to clinical symptoms. b) Coordinated period (March 2010 to December 2011): 41,142 IRT samples were analized. 91 positive first sample IRT detected (0.22%). 71 patients remained for effective follow-up. Four CF diagnosis were made by the algorithm IRT screening-sweat test. Conclusions. In 71 remaining patients after first IRT positive result, CF was diagnosed in four patients. Mean age of diagnosis diminished from 4.54 years to 2.5 months although numbers are small for definitive conclusions. These figures suggest that positive results are the result of coordination and centralization in the CF Center as suggested by many references.