Continuous reference intervals for 21 biochemical and hematological analytes in healthy Chinese children and adolescents: the PRINCE study

The impact of physiological variations on personalized reference intervals and decision limits: an in-depth analysis

The interpretation of laboratory data is a comparative procedure. Physicians typically need reference values to compare patients' laboratory data for clinical decisions. Therefore, establishing reliable reference data is essential for accurate diagnosis and patient monitoring. Human metabolism is a dynamic process. Various types of systematic and random fluctuations in the concentration/activity of biomolecules are observed in response to internal and external factors. In the human body, several biomolecules are under the influence of physiological rhythms and are therefore subject to ultradian, circadian and infradian fluctuations. In addition, most biomolecules are also characterized by random biological variations, which are referred to as biological fluctuations between subjects and within subjects/individuals. In routine practice, reference intervals based on population data are used, which by nature are not designed to capture physiological rhythms and random biological variations. To ensure safe and appropriate interpretation of patient laboratory data, reference intervals should be personalized and estimated using individual data in accordance with systematic and random variations. In this opinion paper, we outline (i) the main variations that contribute to the generation of personalized reference intervals (prRIs), (ii) the theoretical background of prRIs and (iii) propose new methods on how to harmonize prRIs with the systematic and random variations observed in metabolic activity, based on individuals' demography.

Development of next-generation reference interval models to establish reference intervals based on medical data: current status, algorithms and future consideration

Evidence derived from laboratory medicine plays a pivotal role in the diagnosis, treatment monitoring, and prognosis of various diseases. Reference intervals (RIs) are indispensable tools for assessing test results. The accuracy of clinical decision-making relies directly on the appropriateness of RIs. With the increase in real-world studies and advances in computational power, there has been increased interest in establishing RIs using big data. This approach has demonstrated cost-effectiveness and applicability across diverse scenarios, thereby enhancing the overall suitability of the RI to a certain extent. However, challenges persist when tests results are influenced by age and sex. Reliance on a single RI or a grouping of RIs based on age and sex can lead to erroneous interpretation of results with significant implications for clinical decision-making. To address this issue, the development of next generation of reference interval models has arisen at an historic moment. Such models establish a curve relationship to derive continuously changing reference intervals for test results across different age and sex categories. By automatically selecting appropriate RIs based on the age and sex of patients during result interpretation, this approach facilitates clinical decision-making and enhances disease diagnosis/treatment as well as health management practices. Development of next-generation reference interval models use direct or indirect sampling techniques to select reference individuals and then employed curve fitting methods such as splines, polynomial regression and others to establish continuous models. In light of these studies, several observations can be made: Firstly, to date, limited interest has been shown in developing next-generation reference interval models, with only a few models currently available. Secondly, there are a wide range of methods and algorithms for constructing such models, and their diversity may lead to confusion. Thirdly, the process of constructing next-generation reference interval models can be complex, particularly when employing indirect sampling techniques. At present, normative documents pertaining to the development of next-generation reference interval models are lacking. In summary, this review aims to provide an overview of the current state of development of next-generation reference interval models by defining them, highlighting inherent advantages, and addressing existing challenges. It also describes the process, advanced algorithms for model building, the tools required and the diagnosis and validation of models. Additionally, a discussion on the prospects of utilizing big data for developing next-generation reference interval models is presented. The ultimate objective is to equip clinical laboratories with the theoretical framework and practical tools necessary for developing and optimizing next-generation reference interval models to establish next-generation reference intervals while enhancing the use of medical data resources to facilitate precision medicine.

Evaluation of glomerular filtration rate estimation equations based on serum creatinine in healthy Chinese children and adolescents: a nationwide cross-sectional study

BACKGROUND

Several equations for glomerular filtration rate (GFR) estimation based on serum creatinine (SCr) have been proposed for children, but most were developed among patients with kidney disease. The association between SCr and GFR may be distorted by kidney dysfunction and thus not applicable to healthy children. This study aimed to evaluate the applicability of existing SCr-based GFR estimation equations in healthy Chinese children.

METHODS

GFR estimation equations that developed in healthy children were mainly analysed, including the Flanders Metadata (FM), simple height-independent (Simple), full age spectrum (FAS) and FAS-height equations. The FM equation assumed that GFR is proportional to the ratio of height to SCr. The Simple, FAS and FAS-height equations assumed that the ratio of GFR to population mean is equal to the reciprocal ratio of SCr to population mean (denoted by Q). Estimated GFR were calculated using data of SCr, age, sex and height collected from 12 208 healthy Chinese children aged 3 months to <20 years. The performance of GFR estimation equations was evaluated by the sex and age distribution of the estimated GFR and the deviation from the measured GFR reported by other literatures.

RESULTS

The FM and Simple equations performed well in their applicable age of 1 month to 14 years, but presented undesirable sex difference after adolescence. The FAS and FAS-height equations showed reasonable development trend of estimated GFR throughout childhood, and the FAS equation had higher consistency than the FAS-height equation compared with measured GFR in healthy children. The GFR estimated by the FAS equation increased with age before 2 years, and reached the adult level thereafter without important sex difference.

CONCLUSIONS

The FAS equation is applicable to healthy Chinese children.

Reference intervals: past, present, and future

Clinical laboratory test results alone are of little value in diagnosing, treating, and monitoring health conditions; as such, a clinically actionable cutoff or reference interval is required to provide context for result interpretation. Healthcare practitioners base their diagnoses, follow-up treatments, and subsequent testing on these reference points. However, they may not be aware of inherent limitations related to the definition and derivation of reference intervals. Laboratorians are responsible for providing the reference intervals they report with results. Yet, the establishment and verification of reference intervals using conventional direct methods are complicated by resource constraints or unique patient demographics. To facilitate standardized reference interval best practices, multiple global scientific societies are actively drafting guidelines and seeking funding to promote these initiatives. Numerous national and international multicenter collaborations demonstrate the ability to leverage combined resources to conduct large reference interval studies by direct methods. However, not all demographics are equally accessible. Novel indirect methods are attractive solutions that utilize computational methods to define reference distributions and reference intervals from mixed data sets of pathologic and non-pathologic patient test results. In an effort to make reference intervals more accurate and personalized, individual-based reference intervals are shown to be more useful than population-based reference intervals in detecting clinically significant analyte changes in a patient that might otherwise go unrecognized when using wider, population-based reference intervals. Additionally, continuous reference intervals can provide more accurate ranges as compared to age-based partitions for individuals that are near the ends of the age partition. The advantages and disadvantages of different reference interval approaches as well as the advancement of non-conventional reference interval studies are discussed in this review.

Management of complicated choledochal cyst in children: ultrasound-guided percutaneous external drainage and subsequent definitive operation

OBJECTIVE

The purpose of this study was to analyze the outcomes of the combination of ultrasound (US)-guided percutaneous external drainage and subsequent definitive operation to manage complicated choledochal cyst in children.

METHODS

This retrospective study included 6 children with choledochal cyst who underwent initial US-guided percutaneous external drainage and subsequent cyst excision with Roux-en-Y hepaticojejunostomy between January 2021 and September 2022. Patient characteristics, laboratory findings, imaging data, treatment details, and postoperative outcomes were evaluated.

RESULTS

Mean age at presentation was 2.7 ± 2.2 (0.5-6.2) years, and 2 patients (2/6) were boys. Four patients (4/6) had a giant choledochal cyst with the widest diameter of ≥ 10 cm and underwent US-guided percutaneous biliary drainage on admission or after conservative treatments. The other 2 patients (2/6) underwent US-guided percutaneous transhepatic cholangio-drainage and percutaneous transhepatic gallbladder drainage due to coagulopathy, respectively. Five patients (5/6) recovered well after US-guided percutaneous external drainage and underwent the definitive operation, whereas 1 patient (1/6) had liver fibrosis confirmed by Fibroscan and ultimately underwent liver transplantation 2 months after external drainage. The mean time from US-guided percutaneous external drainage to the definitive operation was 12 ± 9 (3-21) days. The average length of hospital stay was 24 ± 9 (16-31) days. No related complications of US-guided percutaneous external drainage occurred during hospitalization. At 10.2 ± 6.8 (1.0-18.0) months follow-up, all patients had a normal liver function and US examination.

CONCLUSIONS

Our detailed analysis of this small cohort suggests that US-guided percutaneous external drainage is technically feasible for choledochal cyst with giant cysts or coagulopathy in children, which may provide suitable conditions for subsequent definitive operation with a good prognosis.

TRIAL REGISTRATION

Retrospectively registered.

Clinical characteristics and prognosis of primary hepatolithiasis in hospitalized children

The purpose of this study is to evaluate the clinical characteristics and prognosis of primary hepatolithiasis in hospitalized children. This retrospective cohort study included 106 hospitalized patients with primary hepatolithiasis at Beijing Children's Hospital. Clinical data were derived from electronic inpatient (2010-2021) and outpatient (2016-2021) medical records. The prognosis was evaluated by outpatient ultrasounds after discharge and telephone interviews performed in December 2022. Intrahepatic bile duct stones in patients enrolled in the study were all found incidentally by abdominal ultrasound during hospitalization, with an incidence of 1.7 per 10,000 hospitalized children. The mean age at diagnosis was 9.3 ± 3.6 years, with male predominance (69/106, 65.1%). The right lobe of the liver (80/106, 75.5%) was preferentially affected. All patients underwent conservative observation. Seventy-eight patients (78/106, 73.6%) were followed up with a mean follow-up age of 17.1 ± 5.0 years, and 4 (4/78, 5.1%) had intermittent abdominal pain. From 2016 to 2021, 32 patients were diagnosed with primary hepatolithiasis, and follow-up abdominal ultrasounds were performed in 20 of them (20/32, 60.0%) with a median time of 2.1 (0.1, 3.5) years. The stones were present in 17 patients (17/20, 85.0%).

CONCLUSION

Primary hepatolithiasis in hospitalized children is rare, almost found accidentally; mostly affects the right lobe of the liver; and can be conservatively observed without surgical treatment in childhood.

WHAT IS KNOWN

• Primary hepatolithiasis in adults often presents with severe clinical symptoms and requires hepatectomy.. • There are few studies on primary hepatolithiasis in children.

WHAT IS NEW

• Primary hepatolithiasis in children is mostly found accidentally by abdominal ultrasound without associated symptoms during hospitalization. • Children with accidental primary hepatolithiasis can be conservatively observed without surgical treatment in childhood.