Perinatal palliative care (PPC) provides essential support for families and healthcare providers at the end-of-life. Despite clear global need, structured PPC programs are not widely established. To develop a PPC program that supports families confronted with a severe perinatal diagnosis for their (unborn) child, with a focus on evidence-based development of such program, ensuring care is effective, consistent, and aligned with best practices. We systematically designed a PPC program following a 7-step method, using Bleijenberg’s extended Medical Research Council framework. We conducted a qualitative interview study with 22 healthcare providers and 18 bereaved parents from six hospitals to identify care gaps alongside an integrative review study of international programs. These combined findings informed the development of a PPC prototype program, intended to be integrated in routine practice. Subsequently, we refined the program, identified barriers to implementation, and explored opportunities for contextual tailoring through six participatory workshops involving both healthcare providers and bereaved parents at three hospitals. In these sessions we reviewed the preliminary care components, identified practical challenges, and adapted the model to align with local workflows, staffing realities, and documentation systems. Five core components were developed: Key barriers to implementation included fragmented documentation systems, limited staffing and time resources, and challenges in cross-departmental coordination. We developed a PPC program based on existing international evidence and current PPC practices. This approach ensured both relevance and practical applicability. The program design is a strength, as it is grounded in evidence and shaped through active involvement of parents and healthcare providers, with attention to contextual tailoring. The program is now ready for pilot testing to assess feasibility and acceptability in clinical practice. Future implementation will require institutional support, contextual adaptation, and ongoing evaluation to ensure sustainable integration into perinatal care.

Purpose Retinopathy of prematurity (ROP) is a blinding disease, however largely preventable by timely detection of severe ROP and treatment when required. Clinical use of the DIGIROP decision support tool (DIGIROP-screen and DIGIROP-birth) can help detecting neonates at high risk of sight-threatening severe ROP needing treatment and to reduce unnecessary screening exams in low-risk infants. External validation is necessary before the tool can be used in clinical decision-making. Methods Retrospective cohort analysis of all preterm infants who were screened for ROP at the University Hospitals Ghent Belgium from January 1, 2020, to December 31, 2022. Validation of the DIGIROP decision support tools was the primary outcome variable. In a secondary analysis pre-, peri-, and postnatal characteristics were compared in different cohorts. Results 311 infants were eligible for routine ROP-screening. Infants with a (gestational age) GA beyond 30 weeks (N = 80) and those who died (N = 19) were excluded resulting in 212 infants eligible entered in DIGIROP-birth. 112 infants did not need to be screened according to DIGIROP-birth. This resulted in 94 infants entered in DIGIROP-screen. These infants had a median GA of 27 weeks, a median birth weight (BW) of 892.5 g, and 62.5% were boys. DIGIROP birth showed a sensitivity of 100%. Most important risk factors for ROP across all subgroups are GA, BW. Conclusions The DIGIROP decision support tool demonstrated very high performance in our setting. However, multicenter prospective validation studies with large cohorts should confirm our findings before the use of the model can be generalized in Western NICU's with similar levels of care.

BACKGROUND:Perinatal palliative care (PPC) is increasingly recognized as an essential component of quality maternity and neonatal care. Despite international calls for structured programs, little is known about how PPC is provided in everyday healthcare systems and how parents and professionals experience it. This study explored PPC practices in Flanders (Belgium), focusing on challenges and opportunities for improving care. METHODS:We conducted a qualitative study using semi-structured face-to-face interviews with healthcare professionals experienced in PPC, and with parents who had lost a child in the perinatal period. A total of 22 healthcare professionals and 18 parents participated. Framework analysis was employed to systematically analyze the interview data. The findings were compared with the results of a recent systematic review which synthesized existing literature and outlined the key components of PPC. RESULTS:In the absence of a formal PPC team, considerable effort was required to coordinate care and ensure effective information transfer between hospitals and departments. Palliative care training was largely informal, with most learning occurring on the job. In contrast to findings reported in the international literature, interview data revealed that external organizations were frequently and systematically involved in PPC. The recognizability of healthcare providers was identified as a key factor in parental psychosocial support. Parents' expressions of gratitude, respect, and satisfaction were experienced by caregivers as highly supportive. In terms of shared decision-making, several parents expressed a need for clearer explanations of medical scenarios, more directive support from physicians, and early exploration of their preferred decision-making style. Simultaneously, both parents and professionals reported feeling limited by legal constraints. Additional needs included improved communication amongst all involved, greater structural support and infrastructure adapted to palliative care needs. CONCLUSIONS:Both parents and healthcare providers pointed out the need for a multidisciplinary team to coordinate PPC across time and disciplines. Parents expressed more dissatisfaction with communication than with the purely medical aspects of care. The importance of caregiver introductions and role clarity, dedicated PPC training and experienced staff was stressed. A neutral, non-directive approach to decision-making did not suit all parents, underscoring the need to tailor support to individual preferences.

Summary: Background & Aims: In 2018, the European Society for Paediatric Gastroenterology, Hepatology and Nutrition (ESPGHAN) updated their guidelines on parenteral nutrition (PN) in pediatric patients, including recommendations for electrolyte and mineral provision. It is unknown how well clinical practice complies with the updated electrolyte and mineral guidelines due to a lack of observational studies. This study assessed concordance with the ESPGHAN 2018 PN guidelines for electrolytes and minerals at the neonatal intensive care unit (NICU) of the Ghent University Hospital. Methods: Retrospective analysis of TPN in neonates admitted to the NICU between December 15, 2013, and December 31, 2014. Patients were stratified according to their birth weight (BW): <1000 g, 1000 g to <1500 g and ≥1500 g. The TPN provision of electrolytes and minerals was compared against ESPGHAN 2018 PN guidelines for up to 14 days after birth. Results: In total, 76 patients were included, 28 with a BW of <1000 g, 10 with a BW of 1000 g to <1500 g and 38 with a BW ≥1500 g. The concordance with ESPGHAN 2018 PN guidelines varied substantially across BW groups and time. For neonates with a BW <1000 g, sodium provision within the 14 days after birth exceeded guideline recommendations in 61–91% of patients, depending on the day. Sodium provision below minimum recommendations was rare, regardless of BW. Only a small fraction of patients received potassium above maximum recommendations. Calcium provision on the first day of life was below recommendations in 50–60% of neonates with BW <1500 g, with similar observations for magnesium provision. The calcium:phosphorus ratio was generally not in range of recommendations. Conclusion: This study provides real-world evidence on ESPGHAN 2018 PN guideline concordance in a NICU. It identifies specific BW groups of neonates and times after birth when available TPN options might be insufficient to achieve guideline recommendations for electrolytes and minerals.

Aim: This study aimed to evaluate changes over time in cause of death and making end-of-life decisions in preterm infants. Methods: A follow-back survey was conducted of all preterm infants who died between September 2016 and December 2017 in Flanders and Brussels, Belgium. Cause of death was obtained from the death certificate and information on end-of-life decisions (ELDs) through an anonymous questionnaire of the certifying physician. Results were compared with a previous study performed between August 1999 and July 2000. Results: In the cohort 1999-2000 and 2016-2017, respectively, 150 and 135 deaths were included. A significantly higher proportion of infants born before 26 weeks of gestation was found in the 2016-2017 cohort (53% vs. 24% in 1999-2000, p < 0.001). Extreme immaturity (<26 weeks) remained the most prevalent cause with a significant increase in the 2016-2017 cohort (48% vs. 28% in 1999-2000, p < 0.001). The overall prevalence of ELDs was similar across study periods (61%). Non-treatment decisions remained the most common ELD (36% and 37%). Conclusion: Infants born at the limits of viability have become more prevalent among infant deaths, possibly due to a change in attitude towards periviable births. Neither the process of making ELDs nor the cause of death has changed over time.

Objective To describe trends in mortality and morbidity rates of very low birth weight infants as well as their pre-, peri- and postnatal characteristics over a period of 20 years' time. Methods Retrospective study in all very low birth weight infants admitted to the neonatal intensive care unit of the University Hospitals Ghent from 1 January 2000, to 31 December 2020. Mortality was the primary outcome variable with major morbidities being co-primary outcome variables. Pre-, peri- and postnatal characteristics are secondary outcome variables. We compared pre-, peri- and postnatal characteristics, as well as major morbidities between different groups with comparable rates of mortality. Results We included a total of 2037 very low birth weight infants and divided them in 3 epochs based on stepwise reductions in mortality in 2008 and 2013: 2000-2007 (n = 718), 2008-2012 (n = 506) and 2013-2020 (n = 813). Mortality decreased significantly over the years in all gestational ages, but predominantly in those with the youngest gestational age. Changes in obstetric and neonatal care were observed over time. Most significant changes were the increased use of antenatal corticosteroids, magnesium sulfate and surfactant. Intraventricular hemorrhage grade III/IV decreased significantly in all gestational ages. Significant increase in retinopathy of prematurity was observed. Bronchopulmonary dysplasia at 36 weeks and discharge home with oxygen is increasing in the total group. In those born below 26 weeks a slight increase in all major morbidities was observed especially of patent ductus arteriosus and retinopathy of prematurity. Increase of all other major morbidities seems to stabilize in epoch 3. The number of infants surviving without any major morbidity increases to almost 1/2 in all very low birth weight infants and to 1/10 in those born 24-25 weeks gestation. Conclusion Analysis of the real-life experience showed that survival in very low birth weight infants significantly increased over time. Evolution of major morbidities will have to be carefully watched in the future.

Parenteral nutrition (PN) is a standard of care for preterm infants in the first postnatal days. The European Society of Paediatric Gastroenterology, Hepatology, and Nutrition (ESPGHAN) has updated their guideline recommendations on PN in 2018. However, data on actual 2018 guideline adherence in clinical practice are sparse. In this retrospective study, conducted at the neonatal intensive care unit (NICU) of Ghent University Hospital, we analyzed the ESPGHAN 2018 PN guideline adherence and growth for 86 neonates admitted to the NICU. Analyses were stratified by birth weight (<1000 g, 1000 to <1500 g, ≥1500 g). We documented the provisions for enteral nutrition (EN) and PN, and we tested the combined EN and PN provisions for ESPGHAN 2018 adherence. The nutrition protocols showed a high adherence to PN guidelines in terms of carbohydrate provisions, yet lipid provisions for EN and PN often exceeded the recommended maximum of 4 g/kg/d; although, PN lipid intakes maxed out at 3.6 g/kg/d. Protein provisions tended to fall below the recommended minimum of 2.5 g/kg/d for preterm infants and 1.5 g/kg/d for term neonates. The energy provisions also tended to fall below the minimum recommendations, especially for neonates with a birth weight (BW) < 1000 g. Over a mean PN duration of 17.1 ± 11.4 d, the median weekly Fenton Z-scores changes for length, weight, and head circumference were positive for all BW groups. Future studies have to assess how protocols adapt to current guidelines, and how this affects short- and long-term growth across different BW groups. In conclusion, the reported findings provide real-world evidence regarding the effect of ESPGHAN 2018 PN guideline adherence, and they demonstrate how standardized neonatal PN solutions can safeguard stable growth during NICU stays.

Objectives Neonatal intensive care has changed extensively over the last decades resulting in improved survival of extreme preterm infants. However, improved survival is associated with prolonged hospitalization, mechanical ventilation and use of invasive devices, which are all predisposing factors for LOS. LOS is known to increase short- and long-term morbidities resulting in impaired neurodevelopmental outcome. Besides treatment with antibiotics and supportive care, there is an unmet need for adjunctive therapies to prevent neonatal sepsis and hereby improve outcome. Methods In a retrospective single-center design, we explored underlying pre-, peri- and postnatal factors in extreme preterm infants with and without LOS to potentially identify future strategies in the prevention of LOS in these infants. Results Associations formerly published could be confirmed, such as lower birth weight, longer duration of respiratory support, parenteral nutrition and NICU stay and a higher incidence of almost all neonatal morbidities. A new interesting finding was the fact that infants with LOS received more antenatal magnesium sulfate (p = 0.002). After nearest neighbor matching based on birth weight, gestational age, gender and multiplicity increased duration of parenteral nutrition and NICU stay, the incidence of PVL remained significantly different between the two groups (LOS/no LOS), but also the association between antenatal magnesium sulfate administration and less LOS held true (p = 0.004). Conclusion In this study, extreme preterm infants receiving antenatal magnesium sulfate developed less LOS. Whether this is merely an associative factor reflecting illness severity or an interesting link for new preventive strategies for LOS, should be further explored.

BACKGROUND:End-of-life decisions with potential life-shortening effect in neonates and infants are common. We aimed to evaluate how often and in what manner neonatologists consult with parents and other healthcare providers in these cases, and whether consultation is dependent on the type of end-of-life decision made.METHODS:Based on all deaths under the age of one that occurred between September 2016 and December 2017 in Flanders, Belgium, a nationwide mortality follow-back survey was performed. The survey asked about different types of end-of-life decisions, and whether and why parents and/or other healthcare providers had or had not been consulted.RESULTS:Response rate was 83% of the total population. End-of-life decisions in neonates and infants were consulted both with parents (92%) and other healthcare providers (90%), and agreement was reached between parents and healthcare providers in most cases (96%). When medication with an explicit life-shortening intent was administered parents were always consulted prior to the decision; however when medication without explicit life-shortening intention was administered parents were not consulted in 25% of the cases.CONCLUSIONS:Shared decision-making between parents and physicians in case of neonatal or infant end-of-life decision-making is the norm in daily practice. All cases without parental consultation concerned non-treatment decisions or comfort medication without explicit life-shortening intention where physicians deemed the medical situation clear and unambiguous. However, we recommend to at least inform parents of medical options, and to explore other possibilities to engage parents in reaching a shared decision. Physicians consult other healthcare providers before making an end-of-life decision in most cases.

ObjectivesNeonatology has undergone important clinical and legal changes; however, the implications for end-of-life decision-making in seriously ill neonates to date are unknown. Our aim was to examine changes in prevalence and characteristics of end-of-life decisions (ELDs) in neonatology.MethodsWe performed a nationwide mortality follow-back survey in August 1999 to July 2000 and September 2016 to December 2017 in Flanders, Belgium. Data were linked to information from death certificates. For each death under the age of 1, physicians were asked to complete an anonymous questionnaire about which ELDs were made preceding death.ResultsThe response rate was 87% in 1999–2000 (253/292) and 83% in 2016–2017 (229/276). The proportion of deaths of infants born before 26 weeks’ gestation was increased (14% vs 34%, p=0.001). Prevalence of ELDs remained stable at 60%, with non-treatment decisions occurring in about 35% of all deaths. Use of medication with an explicit life-shortening intention was prevalent in 7%–10% of all deaths. In early neonatal death (<7 days old) medication with an explicit life-shortening intention decreased from 12% to 6%, in late neonatal death (7–27 days old), it increased from 0% to 26%, and in postneonatal death (>27 days old), it increased from 2% to 10%.ConclusionsOver a timespan of 17 year, the prevalence of neonatal ELDs has remained stable. A substantial number of deaths was preceded by the intentionally hastening of death by administrating medication. While surveying solely the physician perspective in this paper, there is a need for an open multidisciplinary debate, including, for example, nursing staff and family members, based on clinical as well as ethical and jurisdictional reflections to discuss the need for international guidelines.

Critically ill neonates present clinical and ethical challenges. The deaths of these infants are often preceded by possibly life-shortening end-of-life decisions (ELD), including non-treatment decisions or pain and/or symptom relief medication. Recent empirical information about this practice is scarce. We performed a nationwide mortality follow-back survey for all deaths under the age of 1 between September 2016 and December 2017 in Flanders, Belgium. For all death cases identified through death certificates, treating physicians were sent an anonymous questionnaire about which ELDs were made. Details of the method were published elsewhere.1 Response rate was 83% (229/276). In 61% of all deceased infants, an ELD preceded death (table 1). Non-treatment decisions including withholding (12%) and withdrawing treatment (25%) are most prevalent (37%). Drugs are administered in 24% of cases, including medication with a possible (14%) and explicit life-shortening intention (10%). View this table: Table 1 Prevalence of end-of-life decisions (ELDs) …

BACKGROUND:Mortality and end-of-life decision-making can occur in newborns, especially within the Neonatal Intensive Care Unit. For parents, participating in end-of-life decision-making is taxing. Knowledge is lacking on what support is helpful to parents during decision-making.AIM:To identify barriers and facilitators experienced by parents in making an end-of-life decision for their infant.DESIGN:Qualitative study using face-to-face semi-structured interviews.SETTING/PARTICIPANTS:We interviewed 23 parents with a child that died after an end-of-life decision at a Neonatal Intensive Care Unit between April and September 2018.RESULTS:Parents stated barriers and facilitators within 4 themes: 1. Clinical knowledge and prognosis; 2. Quality of information provision; 3. Emotion regulation; and 4. Psychosocial environment. Facilitators include knowing whether the prognosis includes long-term negative quality of life, knowing all treatment options, receiving information according to health literacy level, being able to process intense emotions, having experienced counseling and practical help. Barriers include a lack of general medical knowledge, being unprepared for a poor prognosis, having an uninformed psychologist.CONCLUSIONS:We found that clinical information and psychosocial support aid parents in decision-making. Information is best tailored to health literacy. Psychosocial support can be provided by experienced, informed counselors, social services and sibling support, distinguishing between verbal and non-verbal coping preferences, and calm, familiar architecture. Intense emotions may hinder absorption of clinical information, therefore interventions to aid emotion regulation and reduce cognitive load may be looked at in further research. Adjustment of the Situations, Opinions and Options, Parents, Information, Emotions framework based on our results can be evaluated.

Background: The use of analgesics and sedatives to alleviate pain and discomfort is common in end-of-life care in neonates and infants. However, to what extent those drugs are used in that context with the specific aim of bringing the infant in a state of continuous deep sedation (CDS) is currently unknown. Methods: We performed a nationwide mortality follow-back survey based on all deaths under the age of 1 over a period of 16 months in Flanders, Belgium. Data on CDS were linked to sociodemographic information from death certificates. Physicians completed an anonymous questionnaire. Questions measured whether CDS preceded death, and which clinical characteristics were associated with the sedation (e.g., type of drugs used and the duration of sedation). Results: The response rate was 83% (229/276). In 39% of all deceased neonates and infants, death was preceded by CDS. Physicians used a combination of morphine and benzodiazepines in 53%, or morphine alone in 45% of all sedation cases in order to continuously and deeply sedate the infant. In 89% of cases, death occurred within 1 week after sedation was begun, and in 92% of cases, artificial nutrition and hydration were administered until death. In 49% of cases there was no intention to hasten death, and in 40% of cases, the possibility of hastening was taken into account. Conclusions: CDS precedes about 2 in 5 neonatal and infant deaths. Guidelines for CDS in this age group are non-existent and it is unclear whether the same recommendations as in the adult population apply and can be considered a good practice.

Background: Moral distress and burnout related to end-of-life decisions in neonates is common in neonatologists and nurses working in neonatal intensive care units. Attention to their emotional burden and psychological support in research is lacking. Aim: To evaluate perceived psychological support in relation to end-of-life decisions of neonatologists and nurses working in Flemish neonatal intensive care units and to analyse whether or not this support is sufficient. Design/participants: A self-administered questionnaire was sent to all neonatologists and neonatal nurses of all eight Flemish neonatal intensive care units (Belgium) in May 2017. The response rate was 63% (52/83) for neonatologists and 46% (250/527) for nurses. Respondents indicated their level of agreement (5-point Likert-type scale) with seven statements regarding psychological support. Results: About 70% of neonatologists and nurses reported experiencing more stress than normal when confronted with an end-of-life decision; 86% of neonatologists feel supported by their colleagues when they make end-of-life decisions, 45% of nurses feel that the treating physician listens to their opinion when end-of-life decisions are made. About 60% of both neonatologists and nurses would like more psychological support offered by their department when confronted with end-of-life decisions, and 41% of neonatologists and 50% of nurses stated they did not have enough psychological support from their department when a patient died. Demographic groups did not differ in terms of perceived lack of sufficient support. Conclusion: Even though neonatal intensive care unit colleagues generally support each other in difficult end-of-life decisions, the psychological support provided by their department is currently not sufficient. Professional ad hoc counselling or standard debriefings could substantially improve this perceived lack of support.

Aim Perinatal death is often preceded by an end-of-life decision (ELD). Disparate hospital policies, complex legal frameworks and ethically difficult cases make attitudes important. This study investigated attitudes of neonatologists and nurses towards perinatal ELDs. Methods A survey was handed out to all neonatologists and neonatal nurses in all eight neonatal intensive care units in Flanders, Belgium in May 2017. Respondents indicated agreement with statements regarding perinatal ELDs on a Likert-scale and sent back questionnaires via mail. Results The response rate was 49.5% (302/610). Most neonatologists and nurses found nontreatment decisions such as withholding or withdrawing treatment acceptable (90-100%). Termination of pregnancy when the foetus is viable in cases of severe or lethal foetal problems was considered highly acceptable in both groups (80-98%). Physicians and nurses do not find different ELDs equally acceptable, e.g. nurses more often than physicians (74% vs 60%, p = 0.017) agree that it is acceptable in certain cases to administer medication with the explicit intention of hastening death. Conclusion There was considerable support for both prenatal and neonatal ELDs, even for decisions that currently fall outside the Belgian legal framework. Differences between neonatologists' and nurses' attitudes indicate that both opinions should be heard during ELD-making.

Perinatal death is often preceded by an end-of-life decision (ELD). Disparate hospital policies, complex legal frameworks and ethically difficult cases make attitudes important. This study investigated attitudes of neonatologists and nurses towards perinatal ELDs. A survey was handed out to all neonatologists and neonatal nurses in all eight neonatal intensive care units in Flanders, Belgium in May 2017. Respondents indicated agreement with statements regarding perinatal ELDs on a Likert-scale and sent back questionnaires via mail. The response rate was 49.5% (302/610). Most neonatologists and nurses found nontreatment decisions such as withholding or withdrawing treatment acceptable (90–100%). Termination of pregnancy when the foetus is viable in cases of severe or lethal foetal problems was considered highly acceptable in both groups (80–98%). Physicians and nurses do not find different ELDs equally acceptable, e.g. nurses more often than physicians (74% vs 60%, p = 0.017) agree that it is acceptable in certain cases to administer medication with the explicit intention of hastening death. There was considerable support for both prenatal and neonatal ELDs, even for decisions that currently fall outside the Belgian legal framework. Differences between neonatologists' and nurses' attitudes indicate that both opinions should be heard during ELD-making.

Context. Making end-of-life decisions (ELDs) in neonates involves ethically difficult and distressing dilemmas for health care providers. Insight into which factors complicate or facilitate this decision-making process could be a necessary first step in formulating recommendations to aid future practice. Objectives. This study aimed to identify barriers to and facilitators of the ELD-making process as perceived by neonatologists and nurses. Methods. We conducted semistructured face-to-face interviews with 15 neonatologists and 15 neonatal nurses, recruited through four neonatal intensive care units in Flanders, Belgium. They were asked what factors had facilitated and complicated previous ELD-making processes. Two researchers independently analyzed the data, using thematic content analysis to extract and summarize barriers and facilitators. Results. Barriers and facilitators were found at three distinct levels: the case-specific context (e.g., uncertainty of the diagnosis and specific characteristics of the child, parents, and health care providers, which make decision making more difficult), decision-making process (e.g., multidisciplinary consultations and advance care planning, which make decision making easier), and overarching structure (e.g., lack of privacy and complex legislation making decision making more challenging). Conclusion. Barriers and facilitators found in this study can lead to recommendations, some simpler to implement than others, to aid the complex ELD-making process. Recommendations include establishing regular multidisciplinary meetings to include all health care providers and reduce unnecessary uncertainty, routinely implementing advance care planning in severely ill neonates to make important decisions beforehand, creating privacy for bad-news conversations with parents, and reviewing the complex legal framework of perinatal ELD making. (C) 2019 American Academy of Hospice and Palliative Medicine. Published by Elsevier Inc. All rights reserved.

The death of a child before or shortly after birth is frequently preceded by an end-of-life decision (ELD). Population-based studies of incidence and characteristics of ELDs in neonates and infants are rare, and those in the foetal-infantile period (> 22 weeks of gestation – 1 year) including both neonates and stillborns, are non-existent. However, important information is missed when decisions made before birth are overlooked. Our study protocol addresses this knowledge gap.

Background: Citrulline is considered to be a marker of absorptive enterocyte mass.Citrulline levels can be measured in plasma or dried blood spot (DBS) samples.The purpose of this study is to calculate reference intervals for plasma and DBS citrulline concentrations in children and to examine the effect of age and gender.Methods: In 151 healthy subjects ranging from 1 month to 20 years of age, plasma and DBS citrulline concentration were determined by using Liquid Chromatography-tandem Mass Spectrometry.Citrulline concentrations were examined in relation to age and gender.Reference values were calculated according to the guidelines of the International Federation of Clinical Chemistry and the National Committee on Clinical Laboratory Standards.Results: No significant influence of age and gender could be discerned on plasma or DBS citrulline concentration.In children, the reference intervals for citrulline bounded by the 2.5 and 97.5 percentiles are 13.31-69.05μmol/L and 23.70-49.04μmol/L for plasma and DBS samples respectively.Conclusions: The reference intervals for citrulline levels in healthy children are widely dispersed.Measuring citrulline concentrations in dried blood spots delivers no additional value to plasma measurements for the calculation of reference intervals in children.