4. Discussion
NBS is an important tool in advancing the United Nations Sustainable Development Goal (SDG) 3: Good Health and Well-Being. By enabling early detection of congenital and metabolic disorders, NBS significantly improves health outcomes through timely intervention and treatment. Many countries have developed tailored NBS programs, each designed to address their specific public health needs and target disorders. The expanded NBS program in Thailand has transitioned to a decentralized model, with Srinagarind Hospital uniquely positioned as one of 10 NBS centers. Before decentralization, the NBS program was primarily managed by the Department of Medical Science, Ministry of Public Health, located in Bangkok Metropolitan Region. Srinagarind Hospital is strategically located and optimally placed to serve HR 7 and 8 in northeastern Thailand. Furthermore, it is the only RD Center located outside the Bangkok metropolitan area, providing a distinct advantage in facilitating collaboration with network hospitals. Srinagarind Hospital functions as a one-stop service center for screening, confirmatory testing, and treatment, making it a reliable hub for network hospitals. Its integrated services ensure timely and expert support, including consultations for positive NBS results, initial management recommendations, and rapid patient transfers when necessary.
Its strategic location significantly reduces logistical challenges for the region. For instance, the farthest province in its catchment area, Bueng Kan in HR 8, is approximately 270 km (a little over a 4-hour drive) from Srinagarind Hospital in Khon Kaen. If a baby born in Bueng Kan receives a positive result, the referral to Srinagarind Hospital is far more feasible compared to a referral to Bangkok, which is over 720 km away a journey that would take more than 11 hours by car. This proximity ensures more timely access to confirmatory testing and specialized care, which is critical for conditions requiring immediate intervention.
This disparity highlights a strategic gap in the national NBS program. The Srinagarind model demonstrates the critical importance of aligning NBS and RD Centers within the same catchment area. Such integration shortens processes, ensures timely care, and could significantly improve outcomes for time-sensitive conditions such as IEMs, where delays in diagnosis and treatment can be life-threatening. This model serves as a model for optimizing NBS programs in other regions.
The expanded NBS program in HR 7 and 8 of Thailand has proven to be a valuable model for implementing such initiatives in rural areas of developing countries. This program achieved a screening coverage rate of 98.6%, which is comparable to or exceeds rates reported in many developing countries in Asia [
5].
The NBS coverage rate stands at 98%. However, several factors may contribute to the remaining gap to reach 100% coverage, even after implementing the service across both regions. One key factor is the flexibility of birth registration, which can be completed within 15 days after birth. This flexibility contrasts with NBS, which is conducted at 48 hours of age. Additionally, birth registration can be carried out at any civil registration office, regardless of the baby’s place of birth. Population movement also plays a role, as pregnant women may relocate due to work or be referred to tertiary care hospitals in different areas for delivery. After giving birth, these mothers may register their newborns at a registration office in a different location from the birth hospital. These factors can lead to slight discrepancies between the number of screenings conducted in each region and the number of births reported. To address this, compiling data from all NBS centers nationwide is essential for providing the most accurate representation of screening coverage of Thailand.
Globally, expanded NBS programs in developed countries often report confirmatory rates of over 95% for positive cases, similar to the results achieved for both TSH and IEMs in this study. However, the 96.0% follow-up rate for IEMs was lower than the TSH indicates room for improvement in rural Thailand. Factors such as healthcare access disparities and limited public awareness of metabolic disorders might contribute to this difference.
The recall rates observed in this study were 1 in 425.1 for TSH, with a positive predictive value (PPV) of 0.35, and 1 in 221.0 for IEMs, with a PPV of 0.05. While the recall rate and PPV for TSH fall within acceptable ranges, the recall rate for IEMs indicates a higher burden. This disparity may be attributed to the broader spectrum of disorders included in the screening panel, as well as several potential interferences such as extremely preterm infant, low birth weight, birth asphyxia, and the use of total parenteral nutrition. Additionally, the lower threshold for positive findings in our program may contribute to the higher recall rate for IEMs. These findings highlight the need for ongoing evaluation and refinement of screening protocols to balance sensitivity and specificity, particularly for IEMs, to minimize unnecessary recalls while maintaining effective detection of true positives. Enhanced data collection and analysis regarding the causes of false positives could further optimize the screening process and reduce the burden on families and healthcare systems.
The program identified 101 confirmed cases of CH and 20 confirmed cases of IEMs among the 122,004 newborns screened. The incidence rate of CH was 1 in 1,208 live births, slightly higher than the global average of 1 in 2,000–4,000 births [
6] and Thailand of 1 in 1,708 births [
7]. Further analysis found that Udon Thani province has highest incidence of 1 in 816 births. This finding suggests potential regional or ethnic predispositions. Another factor contributing to the higher CH incidence in this study compared to earlier reports in Thailand may be related to the NBS methodology. The current NBS program for TSH screening may include cases of transient CH, which accounts for approximately 29% of CH diagnoses [
8]. This is likely due to the limited availability of long-term systematic follow-up data for infants diagnosed with CH, which would be necessary to distinguish transient cases from permanent CH. These results emphasize the need for comprehensive follow-up systems to ensure accurate classification and better understanding of CH incidence trends.
The incidence of IEMs in this study was 1 in 6,100 live births, which is twice as high as the rate reported in previous pilot studies conducted in Bangkok, Thailand [
3]. Further investigations revealed regional genetic variations that contribute to this difference. For example, a founder mutation, c.1534C>T (p.Arg512Cys) in the
PCCB gene, associated with propionic aciduria, was identified in Nakhon Phanom province. Additionally, the c.51C>G (p.Phe17Leu) mutation in the
SLC22A5 gene, linked to carnitine uptake deficiency, was found to have a higher prevalence in the Thai population [
9], consistent with its increased allele frequency in East Asian populations, with the Genome Aggregation Database (gnomAD) aggregated allele frequency of 0.001662 [
10]. These findings highlight the influence of genetic diversity on the incidence of IEMs and highlight the importance of region-specific genetic studies to tailor screening and second-tier diagnostic strategies.
Maternal conditions affecting NBS results, such as maternal carnitine deficiency, were identified in six cases. Although these conditions are often asymptomatic in mothers, their detection through NBS can provide significant benefits. Early identification allows for interventions that may prevent or mitigate potential health issues in both childhood and adulthood, such as muscle weakness, fatigue, or more severe metabolic complications. Moreover, detecting maternal conditions highlights an added value of NBS programs: the potential to uncover undiagnosed health issues in mothers. Addressing these conditions not only improves maternal health but also reduces the risk of adverse outcomes in future pregnancies. This highlight the importance of systematic follow-up and family health evaluations when abnormal results are detected, as well as the value of integrating maternal assessments into NBS protocols for comprehensive care.
Our study demonstrated the effectiveness of utilizing technology to streamline the entire NBS process, from sample collection to reporting. The use of electronic ordering by 100% of network hospitals significantly reduced human errors and labor hours in the laboratory process. The coordinators at network hospitals can monitor the real-time status of their samples through the KKU-IEM platform, ensuring transparency and efficiency. The program is continuously developed and updated based on user feedback, ensuring it remains user-friendly and responsive to the needs of the coordinators. This collaborative and iterative approach encourages widespread adoption and ease of use among stakeholders. The reduction in the average time from birth to reporting (from 9.13 days in 2023 to 8.4 days in 2024) highlights the program's commitment to continuous improvement. These enhancements were driven by performance feedback shared at conferences and subsequent workflow adjustments made in collaboration with network hospitals. Faster turnaround times are critical, particularly for conditions such as IEMs, where delays in diagnosis and treatment can result in irreversible developmental delays or even mortality.
Given the program's strong performance, it has been shared with other NBS centers across Thailand to help improve the overall NBS process nationwide. This initiative not only enhances service quality at a regional level but also contributes to a more efficient national NBS system, ensuring better outcomes for affected infants and their families.
The program's geographic analysis revealed variations in the duration from birth to report across provinces, with Bueng Kan demonstrating longer times compared to others. This variability could reflect differences in hospital infrastructure, sample transportation logistics, or personnel training levels. Following the implementation of a knowledge management process in 2024, significant improvements were observed in Bueng Kan province. Adjustments made to the processes in network hospitals resulted in a notable 19.1% reduction in reporting time. This improvement highlights the effectiveness of data-driven interventions and collaborative problem-solving in enhancing service delivery and ensuring more timely care for affected newborns.
The success of the expanded NBS program in rural Thailand emphasizes the feasibility of implementing such initiatives in resource-limited settings. The integration of digital tools, such as the KKU-IEM online platform, played a critical role in streamlining processes from registration to result reporting. Collaboration with TPD for sample logistics ensured timely and efficient transportation, even in remote areas. These innovations can serve as a model for other developing countries seeking to establish or scale up their own NBS programs.
Our NBS program also benefited from a robust quality control system, including participation in international proficiency testing and inter-laboratory comparisons. These measures not only ensured high standards but also aligned the program with global benchmarks, bolstering its credibility and sustainability.
Moving forward, the program should focus on further reducing reporting times, particularly for very urgent conditions, by utilizing real-time data analytics and automated result reporting systems. Expanding public education campaigns on the importance of NBS and involving community health workers in follow-up care could enhance parental compliance and reduce missed follow-ups.
Additionally, conducting long-term outcome studies on affected infants would provide critical insights into the efficacy of early interventions and help shape future policy decisions. Another important step would be to develop second-tier tests for positive results, enhancing diagnostic specificity. The program should also consider including additional diseases that pose significant regional challenges but are preventable or treatable, further broadening its impact.