Evaluation of specificity and sensitivity of IRT/IRT protocol in the cystic fibrosis newborn screening program: 6-year experience of three tertiary centers.

We aimed to evaluate cutoff values of immunoreactive trypsinogen (IRT)/IRT and determine relationship between IRT values and clinical characteristics of children with cystic fibrosis (CF). This study is cross-sectional study. Data of children with positive newborn screening (NBS) between 2015 and 2021 were evaluated in three pediatric pulmonology centers. Age at admission, sex, gestational age, presence of history of meconium ileus, parental consanguinity, sibling with CF, and doll-like face appearance, first and second IRT values, sweat chloride test, fecal elastase, fecal fat, biochemistry results, and age at CF diagnosis were recorded. Sensitivity and specificity of IRT cutoff values were evaluated. Of 815 children with positive NBS, 58 (7.1%) children were diagnosed with CF. Median values of first and second IRT were 157.2 (103.7-247.6) and 113.0 (84.0-201.5) µg/L. IRT values used in current protocol, sensitivity was determined as 96.6%, specificity as 17.2% for first IRT, and 96.6% sensitivity, 20.5% specificity for second IRT. Positive predictive value (PPV) was determined as 7.1%. When cutoff value for first IRT was estimated as 116.7 µg/L, sensitivity was 69.0% and specificity was 69.6%, and when cutoff value was set to 88.7 µg/L for second IRT, sensitivity was 69.0% and specificity was 69.0%. Area under curve was 0.757 for first and 0.763 for second IRT (p < 0.001, p < 0.001, respectively). PPV was calculated as 4.3%.    Conclusion: Although sensitivity of CF NBS is high in our country, its PPV is significantly lower than expected from CF NBS programs. False-positive NBS results could have been overcome by revising NBS strategy. What is Known: • Although immunoreactive trypsinogen elevation is a sensitive test used in cystic fibrosis newborn screening, its specificity is low. • In countries although different algorithms are used, all strategies begin with the measurement of immunoreactive trypsinogen in dried blood spots. What is New: • In our study, it was shown that use of the IRT/IRT protocol for cystic fibrosis newborn screening is not sufficient for the cut-off values determined by the high number of patients. • Newborn screening strategy should be reviewed to reduce false positive newborn screening results.

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

Background/ aim: Since 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 methods: A 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. Results: Nine 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%. Conclusion: This 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.

The Incidence of Cystic Fibrosis in the Central Region of Anatolia in Turkey Between 2015 and 2016

Background: Cystic fibrosis is the most common metabolic chronic disease among European Caucasian children. Cystic fibrosis incidence in Northern Europeans countries is approximately 1 in 3000 births while the worldwide prevalence varies considerably. Aims: To determine the incidence of cystic fibrosis in the central region of Anatolia in Turkey using the newborn screening program data. Study Design: Cross-sectional study Methods: We used the records of the newborn screening program which is implemented by the Konya and Kayseri Provincial Health Directories. Between January 2015 and December 2016, there were a total of 119006 live births in Konya and Kayseri. The newborn screening test was applied to all these babies. Results: During this period, there were 22 live born babies diagnosed with cystic fibrosis in Konya with an incidence of 2.9 per 10000 live births and 13 live born babies diagnosed with cystic fibrosis in Kayseri with an incidence of 2.8 per 10000 live births. In genetic of 30 patients, fifteen patients were homozygous, and 15 patients were a compound heterozygote. Twenty-one different gene variants were detected and the most common mutation was F508del (17/30). Conclusion: We found the incidence of cystic fibrosis in central Anatolia similar to northern European countries.

Neonatal Thyroid-Stimulating Hormone Screening as a Monitoring Tool for Iodine Deficiency in Turkey.

OBJECTIVE: Thyroid-stimulating hormone (TSH) level in neonates is recommended as an indicator for presence of iodine deficiency (ID) at a population level and as a monitoring tool in programs of iodine supplementation. The purpose of this study, based on data from the National Newborn Screening Program (NNSP) for congenital hypothyroidism (CH) in 2014, was to analyze neonatal TSH levels to predict the current status of iodine nutrition in Turkey. METHODS: According to screening methodology, heel-prick blood samples of newborns were collected on filter paper cards usually on day 3-5 after birth (or shortly before discharge). Results of samples collected >48 h after birth were analyzed. The degree of severity of ID was assessed by using the epidemiologic criteria of the World Health Organization (WHO). Elevated TSH levels (>5 mIU/L) were processed and classified according to province, region, birth season, and sampling time. RESULTS: A total of 1,298531 newborns were registered in the NNSP for the CH database. Of those, 1,270311 newborns had screening results collected >48 h after birth and were included in the statistical analyses. The national prevalence of elevated TSH was 7.2%. While the Gaziantep sub-region had the highest TSH elevation rate (15.9%), the Tekirdag sub-region had the lowest rate (4.0%; p<0.001). Seasonal variations were also significant, and the elevated TSH prevalence rate was highest in winter (7.4%; p<0.001). CONCLUSION: National CH screening results suggest that Turkey may still be mildly iodine deficient. Nationwide studies should be performed for direct assessment and monitoring of iodine status in vulnerable populations to confirm accuracy of our results.

The development and organization of newborn screening programs in Turkey.

BACKGROUND: Newborn screening tests have been designed to identify infants with severe disorders that are relatively prevalent and treatable or controllable. Comparing to other countries, the incidence of these diseases are very high in Turkey where the rate of consanguineous marriage is high. METHODS: In this article, it is aimed to evaluate the development and organization of newborn screening programs in Turkey which include phenylketonuria, congenital hypothyroidism and biotinidase deficiency screenings. The point reached today, limitations of the program, expectations and projects for the future are discussed. RESULTS: Today, the point reached in screening programs of the country is appreciable. While the screening rate of the live born babies was 4,7% in 1987, this rate reached to 95% by 2008. Predicted target for newborn screening program at the strategic plan of Ministry of Health for 2010-2014 was to enhance this rate above 95% by the end of 2012. It seems that the envisaged goal has been reached. CONCLUSION: National newborn screening program appears to be conducted successfully and extensively as a result of political determination and performance of health care workers who are in charge of this program. Nevertheless, limited numbers of the nutrition and metabolism clinics and specialists on these branches have caused some access difficulties, waste of time, and financial loss. Therefore, special planning to improve quality and the number of the clinics would be useful.

Establishment and development of a national newborn screening programme for congenital hypothyroidism in Turkey.

OBJECTIVE: To assess the Turkish National Newborn Screening Programme (NNSP) for congenital hypothyroidism (CH). Retrospective study based on the data from NNSP. METHODS: Since December 2006, a nationwide screening programme for CH has been conducted in Turkey by the Turkish Directorate of Public Health (TDPH) in cooperation with several institutions. We evaluated the database between January 2008 and July 2010 of this programme. According to the methodology of the NNSP, between three and five days of age (or at discharge from the hospital, if this occurs earlier) blood specimens were routinely collected from neonates on filter paper, by puncturing the heel. The accepted thyroid-stimulating hormone cut-off level for recall was 20 mU/L initially and 15 mU/L subsequently. The incidence of possible CH by years was reported. RESULTS: During the evaluation period, 3223765 newborns were tested. The mean annual incidence of possible CH showed a gradual increase over the years (1:888 in 2008, 1:592 in 2009, and 1:469 in 2010). Regional differences were noted. Although the mean age of blood sampling did not change by years, the mean age at notification for suspected CH decreased from 19.2 to 15.7 days from 2008 to 2010. CONCLUSIONS: We reported the first assessment of NNSP in Turkey. An improvement in performance measures for the CH screening programme has been noted. Knowledge on incidence of confirmed CH is not yet available in the database.