The Combined Impact of CLIR Post-Analytical Tools and Second Tier Testing on the Performance of Newborn Screening for Disorders of Propionate, Methionine, and Cobalamin Metabolism

Current Status of Newborn Bloodspot Screening Worldwide 2024: A Comprehensive Review of Recent Activities (2020-2023)

Newborn bloodspot screening (NBS) began in the early 1960s based on the work of Dr. Robert "Bob" Guthrie in Buffalo, NY, USA. His development of a screening test for phenylketonuria on blood absorbed onto a special filter paper and transported to a remote testing laboratory began it all. Expansion of NBS to large numbers of asymptomatic congenital conditions flourishes in many settings while it has not yet been realized in others. The need for NBS as an efficient and effective public health prevention strategy that contributes to lowered morbidity and mortality wherever it is sustained is well known in the medical field but not necessarily by political policy makers. Acknowledging the value of national NBS reports published in 2007, the authors collaborated to create a worldwide NBS update in 2015. In a continuing attempt to review the progress of NBS globally, and to move towards a more harmonized and equitable screening system, we have updated our 2015 report with information available at the beginning of 2024. Reports on sub-Saharan Africa and the Caribbean, missing in 2015, have been included. Tables popular in the previous report have been updated with an eye towards harmonized comparisons. To emphasize areas needing attention globally, we have used regional tables containing similar listings of conditions screened, numbers of screening laboratories, and time at which specimen collection is recommended. Discussions are limited to bloodspot screening.

Revolutionizing Blood Collection: Innovations, Applications, and the Potential of Microsampling Technologies for Monitoring Metabolites and Lipids

Blood serves as the primary global biological matrix for health surveillance, disease diagnosis, and response to drug treatment, holding significant promise for personalized medicine. The diverse array of lipids and metabolites in the blood provides a snapshot of both physiological and pathological processes, with many routinely monitored during conventional wellness checks. The conventional method involves intravenous blood collection, extracting a few milliliters via venipuncture, a technique limited to clinical settings due to its dependence on trained personnel. Microsampling methods have evolved to be less invasive (collecting ≤150 µL of capillary blood), user-friendly (enabling self-collection), and suitable for remote collection in longitudinal studies. Dried blood spot (DBS), a pioneering microsampling technique, dominates clinical and research domains. Recent advancements in device technology address critical limitations of classical DBS, specifically variations in hematocrit and volume. This review presents a comprehensive overview of state-of-the-art microsampling devices, emphasizing their applications and potential for monitoring metabolites and lipids in blood. The scope extends to diverse areas, encompassing population studies, nutritional investigations, drug discovery, sports medicine, and multi-omics research.

Combined Newborn Screening Allows Comprehensive Identification also of Attenuated Phenotypes for Methylmalonic Acidurias and Homocystinuria

Newborn screening (NBS) programs are effective measures of secondary prevention and have been successively extended. We aimed to evaluate NBS for methylmalonic acidurias, propionic acidemia, homocystinuria, remethylation disorders and neonatal vitamin B12 deficiency, and report on the identification of cofactor-responsive disease variants. This evaluation of the previously established combined multiple-tier NBS algorithm is part of the prospective pilot study "NGS2025" from August 2016 to September 2022. In 548,707 newborns, the combined algorithm was applied and led to positive NBS results in 458 of them. Overall, 166 newborns (prevalence 1: 3305) were confirmed (positive predictive value: 0.36); specifically, methylmalonic acidurias (N = 5), propionic acidemia (N = 4), remethylation disorders (N = 4), cystathionine beta-synthase (CBS) deficiency (N = 1) and neonatal vitamin B12 deficiency (N = 153). The majority of the identified newborns were asymptomatic at the time of the first NBS report (total: 161/166, inherited metabolic diseases: 9/14, vitamin B12 deficiency: 153/153). Three individuals were cofactor-responsive (methylmalonic acidurias: 2, CBS deficiency: 1), and could be treated by vitamin B12, vitamin B6 respectively, only. In conclusion, the combined NBS algorithm is technically feasible, allows the identification of attenuated and severe disease courses and can be considered to be evaluated for inclusion in national NBS panels.

Biomarkers to predict disease progression and therapeutic response in isolated methylmalonic acidemia

Methylmalonic Acidemia (MMA) is a heterogenous group of inborn errors of metabolism caused by a defect in the methylmalonyl-CoA mutase (MMUT) enzyme or the synthesis and transport of its cofactor, 5'-deoxy-adenosylcobalamin. It is characterized by life-threatening episodes of ketoacidosis, chronic kidney disease, and other multiorgan complications. Liver transplantation can improve patient stability and survival and thus provides clinical and biochemical benchmarks for the development of hepatocyte-targeted genomic therapies. Data are presented from a US natural history protocol that evaluated subjects with different types of MMA including mut-type (N = 91), cblB-type (15), and cblA-type MMA (17), as well as from an Italian cohort of mut-type (N = 19) and cblB-type MMA (N = 2) subjects, including data before and after organ transplantation in both cohorts. Canonical metabolic markers, such as serum methylmalonic acid and propionylcarnitine, are variable and affected by dietary intake and renal function. We have therefore explored the use of the 1-13 C-propionate oxidation breath test (POBT) to measure metabolic capacity and the changes in circulating proteins to assess mitochondrial dysfunction (fibroblast growth factor 21 [FGF21] and growth differentiation factor 15 [GDF15]) and kidney injury (lipocalin-2 [LCN2]). Biomarker concentrations are higher in patients with the severe mut0 -type and cblB-type MMA, correlate with a decreased POBT, and show a significant response postliver transplant. Additional circulating and imaging markers to assess disease burden are necessary to monitor disease progression. A combination of biomarkers reflecting disease severity and multisystem involvement will be needed to help stratify patients for clinical trials and assess the efficacy of new therapies for MMA.

Is Our Newborn Screening Working Well? A Literature Review of Quality Requirements for Newborn Blood Spot Screening (NBS) Infrastructure and Procedures

Newborn screening using dried blood spots (NBS) is widely acknowledged as a highly successful procedure in secondary prevention. For a number of congenital disorders, severe disability or death are impressively prevented by early detection and early treatment through NBS. However, as with any other screening, NBS can also cause harm, and the principle that "the overall benefits of screening should outweigh the harms" must be considered when introducing and implementing NBS programmes. This publication compiles the results of a systematic literature research on requirements for NBS infrastructure and procedures which was conducted as part of a research project on the quality and shortcomings of the NBS pathway in Germany. The compilation contains the requirements and recommendations for realising the principle of "maximise benefits and minimise harms" in relevant NBS pathway components such as parental education and information, coverage, timeliness, laboratory quality assurance, follow-up of abnormal results, confirmatory diagnostics, documentation, and evaluation. The results reflect the complexity of NBS infrastructure, and thus, they illustrate the importance of considering and implementing NBS as a well-coordinated public health programme with continuous quality management. Special attention should be paid to the perspectives of parents and families. Some NBS issues can substantially benefit from digital instruments or international cooperation. The literature review presented here has contributed to a concept of proposals for the advancement of NBS in Germany, and despite different settings, it may as well be of interest for other countries to achieve the best possible course and outcome of NBS for each child.

A computer vision approach to the assessment of dried blood spot size and quality in newborn screening

BACKGROUND

Dried blood spot (DBS) size and quality affect newborn screening (NBS) test results. Visual assessment of DBS quality is subjective.

METHODS

We developed and validated a computer vision (CV) algorithm to measure DBS diameter and identify incorrectly applied blood in images from the Panthera DBS puncher. We used CV to assess historical trends in DBS quality and correlate DBS diameter to NBS analyte concentrations in 130,620 specimens.

RESULTS

CV estimates of DBS diameter were precise (percentage coefficient of variation <1.3%) and demonstrated excellent agreement with digital calipers with a mean (standard deviation) difference of 0.23mm (0.18mm). An optimised logistic regression model showed a sensitivity of 94.3% and specificity of 96.8% for detecting incorrectly applied blood. In a validation set of images (n=40), CV agreed with an expert panel in all acceptable specimens and identified all specimens rejected by the expert panel due to incorrect blood application or DBS diameter >14mm. CV identified a reduction in unsuitable NBS specimens from 25.5% in 2015 to 2% in 2021. Each mm decrease in DBS diameter decreased analyte concentrations by up to 4.3%.

CONCLUSIONS

CV can aid assessment of DBS size and quality to harmonize specimen rejection both within and between laboratories.

Liquid Chromatography-Tandem Mass Spectrometry in Newborn Screening Laboratories

Tandem mass spectrometry (MS/MS) is the most universal platform currently available for the analysis of enzymatic activities and biomarkers in dried blood spots (DBS) for applications in newborn screening (NBS). Among the MS/MS applications in NBS, the most common is flow-injection analysis (FIA-) MS/MS, where the sample is introduced as a bolus injection into the mass spectrometer without the prior fractionation of analytes. Liquid chromatography combined with MS/MS (LC-MS/MS) has been employed for second-tier tests to reduce the false-positive rate associated with several nonspecific screening markers, beginning two decades ago. More recently, LC-MS/MS has been applied to primary screening for new conditions for which FIA-MS/MS or other methods, including genomic screening, are not yet adequate. In addition to providing a list of the currently used LC-MS/MS-based assays for NBS, the authors share their experience regarding the maintenance requirements of LC-MS/MS vs. FIA-MS/MS systems. The consensus is that the maintenance of LC-MS/MS and FIA-MS/MS instrumentation is similar, and LC-MS/MS has the advantage of allowing for a larger number of diseases to be screened for in a multiplex, cost-effective fashion with a high throughput and an adequate turnaround time.

Vitamin B12 (Cobalamin): Its Fate from Ingestion to Metabolism with Particular Emphasis on Diagnostic Approaches of Acquired Neonatal/Infantile Deficiency Detected by Newborn Screening

Acquired vitamin B12 (vB12) deficiency (vB12D) of newborns is relatively frequent as compared with the incidence of inherited diseases included in newborn screening (NBS) of different countries across the globe. Infants may present signs of vB12D before 6 months of age with anemia and/or neurologic symptoms when not diagnosed in asymptomatic state. The possibility of identifying vitamin deficient mothers after their pregnancy during the breastfeeding period could be an additional benefit of the newborn screening. Vitamin supplementation is widely available and easy to administer. However, in many laboratories, vB12D is not included in the national screening program. Optimized screening requires either second-tier testing or analysis of new urine and blood samples combined with multiple clinical and laboratory follow ups. Our scope was to review the physiologic fate of vB12 and the pathobiochemical consequences of vB12D in the human body. Particular emphasis was put on the latest approaches for diagnosis and treatment of vB12D in NBS.

Utilizing augmented artificial intelligence for aminoacidopathies using collaborative laboratory integrated reporting- A cross-sectional study

Introduction

Plasma amino acids profiling can aid in the screening and diagnosis of aminoacidopathies. The goal of the current study was to analyze and report the metabolic profiles of plasma amino acid (PAA) and additionally to compare PAA-reference intervals (RI) from Pakistan with more countries utilizing Clinical Laboratory Integrated Reports (CLIR).

Methods

This was a cross sectional prospective single center study. Twenty-two amino acids were analyzed in each sample received for one year at the clinical laboratory. Data was divided into reference and case data files after interpretation by a team of pathologists and technologists. All PAA samples were analyzed using ion-exchange high-performance chromatography. The CLIR application of Amino Acid in Plasma (AAQP) was used for statistical analysis for both data sets and post-analytical interpretive tools using a single condition tool was applied.

Result

The majority of 92% (n = 1913) of PAA profiles out of the total 2081 tests run were non-diagnostic; the PAA values were within the age-specific RI. The PAA median was in close comparison close to the 50th percentile of reference data available in CLIR software. Out of the total 2081 tests run, one hundred and sixty-eight had abnormal PAA levels; 27.38% were labeled as non-fasting samples, and the main aminoacidopathies identified were Phenylketonuria and Maple Syrup Urine Disorder.

Conclusion

An agreement of >95% was observed between the reporting done by the pathologists and technologists’ team and then after the application of CLIR. Augmented artificial intelligence using CLIR can improve the accuracy of reporting rare aminoacidopathies in a developing country like ours.

•

Plasma amino acids helps in diagnosing and monitoring of various aminoacidopathies.

•

Few aminoacidopathies present with a grossly abnormal investigation profile, with few diseases having subtle deviations.

•

Their is 98% concordance of diagnosis concordance of diagnosis of aminoacidopathies between our lab and CLIR.

•

CLIR tools can be utilized in a newborn screening program for screening and diagnosis in future.

Proximal urea cycle defects are challenging to detect with newborn screening: Results of a prospective pilot study using post-analytical tools

The purpose of this pilot project was to evaluate the efficacy of the Collaborative Integrated Laboratory Reports (CLIR) postanalytical tools from Mayo Clinic for detection of newborns with proximal urea cycle disorders (PUCD) in the Georgia newborn screening program that uses the underivatized Neobase2 kit (Perkin Elmer). We evaluated 138,560 newborn screening (NBS) samples (between 125,000 and 130,000 children) and used the CLIR result interpretation guidelines to stratify results. Children at higher risk of having a PUCD received follow-up services including confirmatory lab testing (ammonia, plasma amino acids, urine orotic acid) or a repeat NBS sample. We made multiple adjustments to our CLIR PUCD tool and to our follow-up algorithms in order to reduce false positives. Regardless, a high number of NBS samples resulted with false positives in part due to the glutamine peak also containing lysine. No children were diagnosed with a PUCD during our study period, and the Emory Genetics Metabolic Center is unaware of any children diagnosed outside of the NBS system during that time. Based on our experience, PUCD is not suitable for statewide NBS using Neobase2 and CLIR. Other methodologies that can separate glutamine from other amino acids may have better performance.

Methionine synthase deficiency: Variable clinical presentation and benefit of early diagnosis and treatment

Methionine synthase deficiency (cblG complementation group) is a rare inborn error of metabolism affecting the homocysteine re-methylation pathway. It leads to a biochemical phenotype of hyperhomocysteinemia and hypomethioninemia. The clinical presentation of cblG is variable, ranging from seizures, encephalopathy, macrocytic anemia, hypotonia, and feeding difficulties in the neonatal period to onset of psychiatric symptoms or acute neurologic changes in adolescence or adulthood. Given the variable and nonspecific symptoms seen in cblG, the diagnosis of affected patients is often delayed. Medical management of cblG includes the use of hydroxocobalamin, betaine, folinic acid, and in some cases methionine supplementation. Treatment has been shown to lead to improvement in the biochemical profile of affected patients, with lowering of total homocysteine levels and increasing methionine levels. However, the published literature contains differing conclusions on whether treatment is effective in changing the natural history of the disease. Herein, we present five patients with cblG who have shown substantial clinical benefit from treatment with objective improvement in their neurologic outcomes. We demonstrate more favorable outcomes in our patients who were treated early in life, especially those who were treated before neurologic symptoms manifested. Given improved outcomes from treatment of presymptomatic patients, cblG warrants inclusion in newborn screening.

Screening for Methylmalonic and Propionic Acidemia: Clinical Outcomes and Follow-Up Recommendations

Wisconsin's newborn screening program implemented second-tier testing on specimens with elevated propionylcarnitine (C3) to aid in the identification of newborns with propionic and methylmalonic acidemias. The differential diagnosis for elevated C3 also includes acquired vitamin B12 deficiency, which is currently categorized as a false positive screen. The goal of this study was to summarize screening data and evaluate their effectiveness at establishing diagnoses and categorizing false positive cases. All Wisconsin newborns born between 2013 and 2019 with a positive first-tier screen for C3 were included in this study. For each case the first- and second-tier newborn screening data and confirmatory test results were compiled. The clinical determination for each case was reviewed and categorized into groups: inborn error of metabolism, maternal B12 deficiency, infant B12 deficiency, and false positive. A review of the screening data showed a significant overlap in the concentration of biomarkers for newborns with genetic versus acquired disease. Additionally, a review of confirmatory test results showed incomplete ascertainment of maternal vitamin B12 status. The Wisconsin newborn screening program recommended a confirmatory testing algorithm to aid in the diagnosis of inborn errors of metabolism and acquired vitamin B12 deficiency.

Analysis of 2-methylcitric acid, methylmalonic acid, and total homocysteine in dried blood spots by LC-MS/MS for application in the newborn screening laboratory: A dual derivatization approach

Inborn errors of propionate, cobalamin and methionine metabolism are targets for Newborn Screening (NBS) in most programs world-wide, and are primarily screened by analyzing for propionyl carnitine (C3) and methionine in dried blood spot (DBS) cards using tandem mass spectrometry (MS/MS). Single-tier NBS approaches using C3 and methionine alone lack specificity, which can lead to an increased false-positive rate if conservative cut-offs are applied to minimize the risk of missing cases. Implementation of liquid chromatography tandem mass spectrometry (LC-MS/MS) second-tier testing for 2-methylcitric acid (MCA), methylmalonic acid (MMA), and homocysteine (HCY) from the same DBS card can improve disease screening performance by reducing the false-positive rate and eliminating the need for repeat specimen collection. However, DBS analysis of MCA, MMA, and HCY by LC-MS/MS is challenging due to limited specimen size and analyte characteristics leading to a combination of low MS/MS sensitivity and poor reverse-phase chromatographic retention. Sufficient MS response and analytical performance can be achieved for MCA by amidation using DAABD-AE and by butylation for MMA and HCY. Herein we describe the validation of a second-tier dual derivatization LC-MS/MS approach to detect elevated MCA, MMA, and HCY in DBS cards for NBS. Clinical utility was demonstrated by retrospective analysis of specimens, an interlaboratory method comparison, and assessment of external proficiency samples. Imprecision was <10.8% CV, with analyte recoveries between 90.2 and 109.4%. Workflows and analytical performance characteristics of this second-tier LC-MS/MS approach are amenable to implementation in the NBS laboratory.

Use of Molecular Genetic Analyses in Danish Routine Newborn Screening

Historically, the analyses used for newborn screening (NBS) were biochemical, but increasingly, molecular genetic analyses are being introduced in the workflow. We describe the application of molecular genetic analyses in the Danish NBS programme and show that second-tier molecular genetic testing is useful to reduce the false positive rate while simultaneously providing information about the precise molecular genetic variant and thus informing therapeutic strategy and easing providing information to parents. When molecular genetic analyses are applied as second-tier testing, valuable functional data from biochemical methods are available and in our view, such targeted NGS technology should be implemented when possible in the NBS workflow. First-tier NGS technology may be a promising future possibility for disorders without a reliable biomarker and as a general approach to increase the adaptability of NBS for a broader range of genetic diseases, which is important in the current landscape of quickly evolving new therapeutic possibilities. However, studies on feasibility, sensitivity, and specificity are needed as well as more insight into what views the general population has towards using genetic analyses in NBS. This may be sensitive to some and could have potentially negative consequences for the NBS programme.

Diagnosis of Classic Homocystinuria in Two Boys Presenting with Acute Cerebral Venous Thrombosis and Neurologic Dysfunction after Normal Newborn Screening

Homocystinuria, caused by cystathionine β-synthase deficiency, is a rare inherited disorder involving metabolism of methionine. Impaired synthesis of cystathionine leads to accumulation of homocysteine that affects several organ systems leading to abnormalities in the skeletal, cardiovascular, ophthalmic and central nervous systems. We report a 14-month-old and a 7-year-old boy who presented with neurologic dysfunction and were found to have cerebral venous sinus thromboses on brain magnetic resonance imaging (MRI)/magnetic resonance venogram (MRV) and metabolic and hypercoagulable work-up were consistent with classic homocystinuria. The 14-month-old boy had normal newborn screening. The 7-year-old boy initially had an abnormal newborn screen for homocystinuria but second tier test that consisted of total homocysteine was normal, so his newborn screen was reported as normal. With the advent of expanded newborn screening many treatable metabolic disorders are detected before affected infants and children become symptomatic. Methionine is the primary target in newborn screening for homocystinuria and total homocysteine is a secondary target. Screening is usually performed after 24-48 h of life in most states in the US and some states perform a second screen as a policy on all tested newborns or based on when the initial newborn screen was performed. This is done in hopes of detecting infants who may have been missed on their first screen. In the United Kingdom, NBS using dried blood spot is performed at 5 to 8 days after birth. It is universally known that methionine is a poor target and newborn screening laboratories have used different cutoffs for a positive screen. Reducing the methionine cutoff increases the sensitivity but not necessarily the specificity of the test and increasing the cutoff will miss babies who may have HCU whose levels may not be high enough to be detected at their age of ascertainment. It is not clear whether adjusting methionine level to decrease the false negative rates combined with total homocysteine as a second-tier test can be used effectively and feasibly to detect newborns with HCU. Between December 2005 and December 2020, 827,083 newborns were screened in Kentucky by MS/MS. Kentucky NBS program uses the postanalytical tools offered by the Collaborative Laboratory Integrated Reports (CLIR) project which considers gestational age and birthweight. One case of classical homocystinuria was detected and two were missed on first and second tier tests respectively. The newborn that had confirmed classical homocystinuria was one of twenty-three newborns that were referred for second tier test because of elevated methionine (cutoff is >60 µmol/L) and/or Met/Phe ratio (cutoff is >1.0); all 23 dried blood spots had elevated total homocysteine. One of the subjects of this case report had a normal methionine on initial screen and the other had a normal second-tier total homocysteine level. The performance of methionine and total homocysteine as screening analytes for homocystinuria suggest that it may be time for newborn screening programs to consider adopting next generation sequencing (NGS) platforms as alternate modality of metabolic newborn screening. Because of cost considerations, newborn screening programs may not want to adopt NGS, but the downstream healthcare cost incurred due to missed cases and the associated morbidity of affected persons far exceed costs to newborn screen programs. Since NGS is becoming more widely available and inexpensive, it may be feasible to change testing algorithms to use Newborn Metabolic NGS as the primary mode of testing on dry blood specimens with confirmation with biochemical testing. Some commercial laboratories have Newborn Screening Metabolic gene panel that includes all metabolic disorders on the most comprehensive newborn screening panel in addition to many other conditions that are not on the panel. A more targeted NGS panel can be designed that may not cost much and eventually help avoid the pitfalls associated with delayed diagnosis and cost of screening.

Pilot Study on Neonatal Screening for Methylmalonic Acidemia Caused by Defects in the Adenosylcobalamin Synthesis Pathway and Homocystinuria Caused by Defects in Homocysteine Remethylation

Neonatal screening (NS) for methylmalonic acidemia uses propionylcarnitine (C3) as a primary index, which is insufficiently sensitive at detecting methylmalonic acidemia caused by defects in the adenosylcobalamin synthesis pathway. Moreover, homocystinuria from cystathionine β-synthase deficiency is screened by detecting hypermethioninemia, but methionine levels decrease in homocystinuria caused by defects in homocysteine remethylation. To establish NS detection of methylmalonic acidemia and homocystinuria of these subtypes, we evaluated the utility of indices (1) C3 ≥ 3.6 μmol/L and C3/acetylcarnitine (C2) ≥ 0.23, (2) C3/methionine ≥ 0.25, and (3) methionine < 10 μmol/L, by retrospectively applying them to NS data of 59,207 newborns. We found positive results in 116 subjects for index (1), 37 for (2), and 15 for (3). Second-tier tests revealed that for index 1, methylmalonate (MMA) was elevated in two cases, and MMA and total homocysteine (tHcy) were elevated in two cases; for index 2 that MMA was elevated in one case; and for index 3 that tHcy was elevated in one case. Though data were anonymized, two cases identified by index 1 had been diagnosed with maternal vitamin B₁₂ deficiency during NS. Methylene tetrahydrofolate reductase deficiency was confirmed for the case identified by index 3, which was examined because an elder sibling was affected by the same disease. Based on these data, a prospective NS study is underway.

A Novel Approach to Improve Newborn Screening for Congenital Hypothyroidism by Integrating Covariate-Adjusted Results of Different Tests into CLIR Customized Interpretive Tools

Newborn screening for congenital hypothyroidism remains challenging decades after broad implementation worldwide. Testing protocols are not uniform in terms of targets (TSH and/or T4) and protocols (parallel vs. sequential testing; one or two specimen collection times), and specificity (with or without collection of a second specimen) is overall poor. The purpose of this retrospective study is to investigate the potential impact of multivariate pattern recognition software (CLIR) to improve the post-analytical interpretation of screening results. Seven programs contributed reference data (N = 1,970,536) and two sets of true (TP, N = 1369 combined) and false (FP, N = 15,201) positive cases for validation and verification purposes, respectively. Data were adjusted for age at collection, birth weight, and location using polynomial regression models of the fifth degree to create three-dimensional regression surfaces. Customized Single Condition Tools and Dual Scatter Plots were created using CLIR to optimize the differential diagnosis between TP and FP cases in the validation set. Verification testing correctly identified 446/454 (98%) of the TP cases, and could have prevented 1931/5447 (35%) of the FP cases, with variable impact among locations (range 4% to 50%). CLIR tools either as made here or preferably standardized to the recommended uniform screening panel could improve performance of newborn screening for congenital hypothyroidism.

Development of Strategies to Decrease False Positive Results in Newborn Screening

The expansion of national newborn screening (NBS) programmes has provided significant benefits in the diagnosis and early treatment of several rare, heritable conditions, preventing adverse health outcomes for most affected infants. New technological developments have enabled the implementation of testing panel covering over 50 disorders. Consequently, the increment of false positive rate has led to a high number of healthy infants recalled for expensive and often invasive additional testing, opening a debate about the harm-benefit ratio of the expanded newborn screening. The false-positive rate represents a challenge for healthcare providers working in NBS systems. Here, we give an overview on the most commonly used strategies for decreasing the adverse effects due to inconclusive screening results. The focus is on NBS performance improvement through the implementation of analytical methods, the application of new and more informative biomarkers, and by using post-analytical interpretive tools. These strategies, used as part of the NBS process, can to enhance the positive predictive value of the test and reduce the parental anxiety and healthcare costs related to the unnecessary tests and procedures.

Identifying and overcoming barriers to harmonize newborn screening programs through consensus strategies

The benefits of newborn screening (NBS) programs have been widely demonstrated after more than 50 years since first established. NBS enables the detection of the disease before the child shows clinical symptoms, allowing clinicians to act early and facilitating appropriate interventions to prevent or improve adverse outcomes. Delay or lack of medical intervention in these infants may lead to developmental delay, severe disability, or premature death. NBS programs have grown exponentially both in the number of diseases screened and in complexity, creating controversy. New technological advances, as well as the emergence of new therapies that require early disease detection, have allowed for the inclusion of new diseases in NBS screening programs. However, different countries and even different regions have in turn adopted very diverse strategies and diagnostic algorithms when it comes to NBS. There are many factors responsible for these differences, such as the health care system, available funds, local politics, professional groups, and others that depend on the position taken by policymakers. These differences in NBS have led to discrepancies in detection opportunities between countries or regions, which has led to many varied attempts to harmonize NBS programs but not all have been equally satisfactory. Some countries have achieved good results, but always within their borders. Therefore, there are still many differences between NBS programs at the international level that must be overcome. These advances have also brought considerable uncertainty regarding ethical aspects and balance between benefits and harms. For this reason, and so that the situation of disparity in the global NBS programs can be minimized, health authorities must work to develop uniform criteria for decision-making and to take a further step toward harmonization. To do so, it is necessary to identify the crucial factors that lead to the adoption of different NBS programs worldwide, in order to analyze their influence and find ways to overcome them.