Laboratory Anomalies in the Basic Metabolic Panel: Core Curriculum 2025.

Laboratory testing plays an integral part in medical decision making. However, laboratory results can sometimes vary significantly, leading to anomalous outcomes that are not consistent with the clinical picture. These anomalies can occur even in the best of laboratories simply because the total testing process includes elements that are not totally under the laboratory's control. For example, variations in patient preparation and sample collection procedures, as can happen at physician offices or patients receiving intravenous fluids, are major contributors to these anomalies. Therefore, physicians must remain aware of the causes of these anomalies so they can consider them when interpreting laboratory results and help implement solutions to mitigate them at their respective institutions. This Core Curriculum examines several instances where an understanding of preanalytical, analytical, and postanalytical variation is essential for detecting anomalies and providing proper patient care.

Mucosal epithelial homeostasis: Reference intervals for skin, gill lamellae and filament for Atlantic salmon and other fish species.

Mucosal barriers are gatekeepers of health and exhibit homeostatic variation in relation to habitat and disease. Mucosal Mapping technology provides an in-depth examination of the dynamic mucous cells (MCs) in fish mucosal barriers on tangential sections, about 90° from the view of traditional histology. The method was originally developed and standardized in academia prior to the establishment of QuantiDoc AS to apply mucosal mapping, now trademarked as Veribarr™ for the analysis of skin, gills and gastrointestinal tracts. Veribarr™ uses design-based stereology for the selection and measurement of cell area (size) (µm2), the volumetric density of MCs in the epithelium (MCD, amount of the epithelia occupied by MCs, in %) and the calculated abundance of the MCs (barrier status or defence activity). MC production was mapped across the skin and gill epithelia in 12 species, discovering that gills consistently have two distinct groups of MCs, one on the lamellae where MCs are few and small and one on the filament where MCs are larger and more abundant. MCs were usually much larger in the skin than in the gills, with the latter requiring fewer and smaller cells for adequate respiration. The difference observed between MCs in gill lamella and gill filament is likely a result of functional demands. In addition, our findings also highlight a variation in the mucosal parameters between the species skin, which cannot be explained by the weight differences, and a potential link between MC distribution and species-specific lifestyles in the gill lamella. This diversity necessitates the development of species and tissue site-specific reference intervals for mucosal health evaluation. Mucosal bivariate reference intervals were developed for MC production, including size (trophy) and calculated defence activity (plasia) in the skin and gills of Atlantic salmon, to contrast new measurements against historical data patterns. The application of mucosal reference intervals demonstrates that stress from parasites and treatments can manifest as changes in mucosal architecture, as evidenced by MC hypertrophy and hyperplasia within the gill lamellae. These reference intervals also facilitate comparisons with wild Atlantic salmon, revealing a somewhat higher MC level in farmed salmon gill lamellae. These findings suggest that MC hyperplasia and hypertrophy in the gills are stress/environmental responses in aquaculture. They also advocate for developing specific mucosal bivariate homeostatic reference intervals in aquaculture to improve fish health and welfare across all farmed species.

Establishment of Reference Intervals for Common Renal and Liver Function Parameters in Healthy Adults in Mogadishu, Somalia: A Cross-Sectional Study.

Introduction: Reference intervals (RIs) are crucial for the accurate interpretating of laboratory test results in clinical settings, serving as benchmarks for evaluating individual health status. This study investigates the influence of sex and age on common liver function tests (LFTs) and renal function tests (RFTs) in healthy adults in Mogadishu, Somalia. Methods: A community-based cross-sectional study was carried out from October 2022 to January 2023 on a randomly selected sample of 255 healthy participants from Mogadishu, Somalia. Approximately 5 mL of whole blood was collected from each participant and processed screening of hepatitis B and C, and human immunodeficiency virus, and then biochemical analyses were conducted for common liver and kidney parameters. Results: The study found significant sex and age-related differences in the measured LFTs and RFTs parameters. For LFTs, males had higher levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) compared to females (ALT: 11.5 vs 7.5 U/L; AST: 25.5 vs 19.1 U/L; both p < 0.001). Age-related differences were also observed, with individuals aged 30 and above had higher levels of ALT and AST compared to those aged 18-29 (ALT: 10.9 vs 8.5 U/L; AST: 24.3 U/L vs 21.0 U/L, both p < 0.001). For RFTs, males had higher levels of creatinine (0.9 vs 0.7 mg/dL), urea (23.1 vs 16.1 mg/dL), and uric acid (5.2 vs 4.2 mg/dL) than females, all with p < 0.001. Conclusion: The study established population specific RIs for common liver and renal function parameters and revealed significant variations across sex and age groups. These findings underscore the importance of developing and using local RIs to ensure accurate clinical interpretation and effective patient management. Further research with larger sample sizes and in diverse regions of Somalia is highly recommended.

Agreement of lymphocyte subsets detection permits reference intervals transference between flow cytometry systems: direct validation using established reference intervals.

OBJECTIVES: With the increasing demand and application of lymphocyte subsets detection in clinical laboratories, different single-platform flow cytometer (FCM) systems have been developed. There is an urgent need to establish the reference intervals (RIs) for different single-platform FCMs and transferring them from one FCM system to another provides a much more feasible and convenient approach. This study aimed to explore the transferability of RIs for lymphocyte subsets across different flow cytometry platforms. METHODS: We first conducted the pairwise method comparison across four FCM platforms, including NovoCyte, BriCyteE6, DxFLEX, and FACSCantoII systems. Next, the transferability of RIs of lymphocyte subsets was evaluated. Furthermore, we conducted the RIs transference based on the FACSCantoII system, BriCyteE6 system and DxFLEX system, except for NK cells. The transferred RIs were further verified by calculating the bias (CV) between the established ones. RESULTS: The results of lymphocyte subsets detection based on the NovoCyte, BriCyteE6, DxFLEX, and FACSCantoII systems were comparable and it was feasible to transfer the RIs of lymphocyte subsets detected by the four FCM systems. The RIs of lymphocyte subsets detection using FACSCantoII, DxFLEX, and BriCyteE6 systems were established. Upon transferring the RIs of lymphocyte subsets from the FACSCantoII system to the BriCyteE6 system, and DxFLEX system except for NK cells, the CV between the transferred RIs and the established ones was below 20 % for all parameters. CONCLUSIONS: The present study illustrated that the RIs of lymphocyte subsets could be transferred across different flow cytometry systems except for NK cells with different definition strategies.

Fetal sexual dimorphism of maternal thyroid function parameters during pregnancy, a single center retrospective real-world study.

Introduction: Thyroid function during pregnancy fluctuates with gestational weeks, seasons and other factors. However, it is currently unknown whether there is a fetal sex-specific thyroid function in pregnant women. The purpose of this study was to investigate the fetal sex differences of maternal thyroid-stimulating hormone (TSH) and free thyroxine (FT4) in pregnant women. Methods: This single-center retrospective real-world study was performed by reviewing the medical records of pregnant women who received regular antenatal health care and delivered liveborn infants in Shanghai First Maternity and Infant Hospital (Pudong branch), from Aug. 18, 2013 to Jul. 18, 2020. Quantile regression was used to evaluate the relationship between various variables and TSH and FT4 concentrations. The quantile regression also evaluated the sex impact of different gestational weeks on the median of TSH and FT4. Results: A total of 69,243 pregnant women with a mean age of 30.36 years were included. 36197 (52.28%) deliveries were boys. In the three different trimesters, the median levels (interquartile range) of TSH were 1.18 (0.66, 1.82) mIU/L and 1.39 (0.85, 2.05) mIU/L, 1.70 (1.19, 2.40) mIU/L; and the median levels (interquartile range) of FT4 were 16.63 (15.16, 18.31) pmol/L, 14.09 (12.30, 16.20) pmol/L and 13.40 (11.52, 14.71) pmol/L, respectively. The maternal TSH upper limit of reference ranges was decreased more in mothers with female fetuses during gestational weeks 7 to 12, while their FT4 upper limit of the reference ranges was increased more than those with male fetuses. After model adjustment, the median TSH level was 0.11 mIU/L lower (P <0.001), and FT4 level was 0.14 pmol/L higher (P <0.001) for mothers with female fetuses than those with male fetuses during gestational weeks 9 to 12. Discussion: We identified sexual dimorphism in maternal thyroid function parameters, especially during 9-12 weeks of pregnancy. Based on previous research, we speculated that it may be related to the higher HCG levels of mothers who were pregnant with girls during this period. However, longitudinal studies are needed to determine if fetal sex differences impact the maternal thyroid function across pregnancy.

Establishment of reference intervals of thyroid-related hormones for adults with normal liver function in Zhejiang Province by indirect method.

Objective: Thyroid disorders are prevalently diagnosed yet face significant challenges in their accurate identification in China. Predominantly, the reference intervals (RIs) currently in use across Chinese medical facilities derive from company-provided data, lacking stringent scientific validation. This practice underscores the urgent necessity for establishing tailored RIs for thyroid-related hormones, specifically tailored to the coastal area populations. Such refined RIs are imperative for empowering clinicians with the precise tools needed for the accurate diagnosis of both overt and subclinical thyroid conditions. Methods: This investigation analyzed the medical histories of 6021 euthyroid individuals mainly from East coastal area of China between June 2019 and December 2020. The cohort comprised residents of coastal areas, focusing on extracting insights into the regional specificity of thyroid hormone levels. A thorough examination protocol was implemented, encompassing inquiries into thyroid health history, ultrasound screenings, palpations during thyroid surgery, detections of thyroid antibodies, and reviews of medication histories. Adherence to the CLSI C28-A3 guidelines facilitated the derivation of RIs for thyroid-related hormones, subsequently juxtaposed against those provided by commercial entities. Results: The study delineated the following gender- and age-specific RIs for Thyroid-Stimulating Hormone (TSH): for males under 50 years, 0.57-3.37; males over 50 years, 0.51-4.03; females under 50 years, 0.53-3.91; and females over 50 years, 0.63-4.31. Further analysis revealed the RIs for Free Thyroxine (FT4), Free Triiodothyronine (FT3), Total Thyroxine (TT4), and Total Triiodothyronine (TT3) amongst males and females, with notable distinctions observed between the two genders and across age brackets. These findings are in stark contrast to the standardized intervals provided by manufacturers, particularly highlighting differences in TT3 and FT3 levels between genders and a tendency for TSH levels to increase with age. Conclusion: This research successfully establishes refined RIs for thyroid-related hormones within the Chinese coastal area populations, taking into account critical demographic factors such as gender and age. These tailored RIs are anticipated to significantly enhance the diagnostic accuracy for thyroid diseases, addressing the previously noted discrepancies with manufacturer-provided data and underscoring the importance of regionally and demographically adjusted reference intervals in clinical practice.

Age-Specific Reference Intervals for Thyroid-Stimulating Hormones and Free Thyroxine to Optimize Diagnosis of Thyroid Disease.

Background: Thyroid-stimulating hormone (TSH) and subsequent free thyroxine (FT4) concentrations outside the reference interval (RI) are used to diagnose thyroid diseases. Most laboratories do not provide age-specific RIs for TSH and FT4 beyond childhood, although TSH concentrations vary with age. Therefore, we aimed to establish TSH and FT4 age-specific RIs throughout life and aimed to determine whether using these RIs would result in reclassification of thyroid disease diagnoses in adults. Methods: This multicenter retrospective cross-sectional study used big data to determine indirect RIs for TSH and FT4. These RIs were determined by TMC and refineR-analysis, respectively, using four different immunoassay platforms (Roche, Abbott, Siemens, and Beckman Coulter). Retrospective data (2008-2022) from 13 Dutch laboratories for general practitioners and local hospitals were used. RIs were evaluated per manufacturer. Age groups were established from 2 to 20 years by 2-year categories and decade categories between 20 and 100 years. Results: We included totally 7.6 million TSH and 2.2 million FT4 requests. TSH upper reference limits (URLs) and FT4 lower reference limits were higher in early childhood and decreased toward adulthood. In adulthood, TSH URLs increased from 60 years in men, and from 50 years in women, while FT4 URLs increased from 70 years onward. Using adult age-specific RIs resulted in a decrease in diagnoses of subclinical and overt hypothyroidism in women above 50 and men above 60 years in our Roche dataset. Conclusion: This study stressed the known importance of using age-specific RIs for TSH and FT4 in children. This study also showed the clinical relevance of using age-specific RIs for TSH in adulthood to reduce diagnoses of subclinical hypothyroidism in older persons. Therefore, implementation of adult TSH age-specific RIs should be strongly considered. Data are less uniform regarding FT4 age-specific RIs and more research should be performed before implementing these in clinical practice.

Population-based anti-Müllerian hormone reference intervals help define gonadal status in the bitch.

OBJECTIVE: To establish statistically valid, population-based reference intervals (RIs) for canine anti-Müllerian hormone (AMH) and define changes in AMH and inhibin-B in bitches during breeding cycles. METHODS: A homologous canine ELISA was used to measure AMH in serum samples (collected between May 2019 and July 2024) from 102 intact and 78 reportedly ovariohysterectomized (OVH) bitches and 8 bitches before and after ovariohysterectomy, and in longitudinal samples from 24 bitches undergoing breeding management. Established 95% RIs were used in a retrospective assessment of 3,193 clinical submissions. Cyclic variation of AMH and inhibin-B (heterologous ELISA) were regressed with time and normalized to the rise in progesterone in samples from breeding bitches. RESULTS: Intact and OVH RIs for AMH were calculated with and without inclusion of 7 samples from reportedly OVH bitches that had AMH concentrations in the intact RI. Anti-Müllerian hormone and inhibin-B were positively correlated, and AMH was 3 times higher in proestrus than in estrus. Retrospectively, of 3,193 samples submitted for clinical AMH testing, 41% to 56% were in or above the intact AMH interval, 37% to 44% were within the OVH interval, and < 10% were inconclusive, depending on how RIs were defined. CONCLUSIONS: Statistically valid, population-based RIs establish a sound basis for interpreting results of clinical submissions requesting AMH to assess gonadal status in the bitch. CLINICAL RELEVANCE: Confirmation of cyclic variation in AMH (and, for the first time, inhibin-B) reaffirms proestrus as the optimum time to draw samples, and ≤ 10% of samples submitted for determination of gonadal status are expected to fall in an inconclusive AMH RI.

Establishment of tumor marker reference intervals for different age and gender groups in the healthy population of South China.

To establish age- and sex-specific reference intervals (RIs) for serum tumor markers (AFP, CEA, CA125, CA199, CA153, HE4, CA724, CYFRA21-1, PSA, and NSE) among a cohort of healthy individuals in South China, a retrospective analysis was conducted on 51,353 samples collected from 2015 to 2020, during health assessments at Guangdong Provincial People's Hospital. The influence of age and gender on serum tumor markers was investigated. New RIs were determined using non-parametric rank-based methods per CLSI EP28-A3C guidelines. Significant differences were detected across age groups for AFP, CEA, CA125, CA199, HE4, CYFRA21-1, PSA, and NSE (p < 0.05). The upper reference limits (URLs) for CA153 and HE4 are significantly lower compared to our current laboratory standards. The URL for CA125 exceeds these limits in individuals under 50 but decreases in those aged 50 and above. For CA199, CEA, and PSA, the URLs are below current standards in individuals younger than 60 but exceed them in those aged 60 and older. Noteworthy elevations were observed in CA724, CYFRA21-1, and NSE levels. Our study establishes age- and sex-specific RIs for ten serum tumor markers among healthy individuals from South China, providing a fundamental resource for the prevention, early detection, and management of tumor-related disorders.

Health assessment of nesting loggerhead sea turtles (Caretta caretta) in one of their largest rookeries (central eastern Florida coast, USA).

Reproduction is a physiologically demanding process for sea turtles. Health indicators, including morphometric indices and blood analytes, provide insight into overall health, physiology and organ function for breeding sea turtles as a way to assess population-level effects. The Archie Carr National Wildlife Refuge (ACNWR) on Florida's central eastern coast is critical nesting habitat for loggerhead sea turtles (Caretta caretta), but health variables from this location have not been documented. Objectives of the study were to (1) assess morphometrics and blood analyte data (including haematology, plasma biochemistry, protein electrophoresis, ß-hydroxybutyrate, trace nutrients, vitamins and fatty acid profiles) from loggerheads nesting on or near the beaches of the ACNWR, (2) investigate correlations of body condition index (BCI) with blood analytes and (3) analyse temporal trends in morphometric and blood analyte data throughout the nesting season. Morphometric and/or blood analyte data are reported for 57 nesting loggerheads encountered between 2016 and 2019. Plasma copper and iron positively correlated with BCI. Mass tended to decline across nesting season, whereas BCI did not. Many blood analytes significantly increased or decreased across nesting season, reflecting the catabolic state and haemodynamic variations of nesting turtles. Twenty-three of 34 fatty acids declined across nesting season, which demonstrates the physiological demands of nesting turtles for vitellogenesis and reproductive activities, thus suggesting potential utility of fatty acids for the assessment of foraging status and phases of reproduction. The findings herein are relevant for future spatiotemporal and interspecies comparisons, investigating stressor effects and understanding the physiological demands in nesting sea turtles. This information provides comparative data for individual animals in rescue or managed care settings and for assessment of conservation strategies.

Sex- and age-based reference intervals for capillary complete blood count parameters among urban preschoolers in southeast China based on a large community population.

Background and aim: Pediatricians commonly use the complete blood count (CBC) of capillary blood to evaluate health status, guide diagnoses, and determine treatment strategies. This study aimed to establish sex- and age-specific reference intervals (RIs) for 23 capillary CBC parameters for urban preschoolers in Fuzhou, Southeast China. Materials and methods: Capillary blood CBC data of 18,369 healthy preschoolers who underwent annual physical examinations at Fujian Maternity and Child Health Hospital between January 01, 2022, and November 31, 2023, were analyzed retrospectively. To fully validate the new RIs, the data of all apparently healthy children within the same age cohort at the same institution were comprehensively analyzed in December 2023. The new RIs were assessed by comparing them with the RIs currently used in laboratories and those obtained from different regions, sample types, or methodologies. Results: Dynamic temporal changes that differ between males and females were observed in the blood system of 3-7-year-old children in this region. The new sex- and age-specific RIs for capillary CBC parameters were feasible to guide clinical decision-making in the local region. Conclusions: Our findings demonstrated the importance of establishing sex- and age-specific RIs for each region and underscored the necessity of continuous adjustment of clinical Rls based on statistical rules and clinical responses.

LC-MS/MS-based bioanalysis of branched-chain and aromatic amino acids in human serum.

Aim: Branched-chain amino acids (BCAAs) and aromatic amino acids (AAAs) were suggested as potential biomarkers in liver disease. This study aimed to develop and validate a simple and rapid LC-MS/MS method to simultaneously measure serum BCAAs and AAAs levels in patients with liver injury, and further establish reference intervals of Chinese healthy adult populations.Patients & methods: Samples were prepared by a one-step protein precipitation and analysis time was 4 min per run.Results: The validation results showed good linearity (r2 >0.9969), satisfactory accuracy (94.44% - 107.75%) and precision (0.10% - 5.90%).Conclusion: This method proved to be suitable for high-throughput routine clinical use and could be a valuable adjunct diagnosis tool for liver injury and other clinical applications.

[Box: see text].

Clinical utility of personalized reference intervals for CEA in the early detection of oncologic disease.

OBJECTIVES: Personalized reference intervals (prRI) have been proposed as a diagnostic tool for assessing measurands with high individuality. Here, we evaluate clinical performance of prRI using carcinoembryonic antigen (CEA) for cancer detection and compare it with that of reference change values (RCV) and other criteria recommended by clinical guidelines (e.g. 25 % of change between consecutive CEA results (RV25) and the cut-off point of 5 µg/L (CP5)). METHODS: Clinical and analytical data from 2,638 patients collected over 19 years were retrospectively evaluated. A total 15,485 CEA results were studied. For each patient, we calculated prRI and RCV using computer algorithms based on the combination of different strategies to assess the number of CEA results needed, consideration of one or two limits of reference interval and the intraindividual biological variation estimate (CVI) used: (a) publicly available (CVI-EU), (b) CVI calculated using an indirect method (CVI-NOO) and (c) within-person BV (CVP). For each new result identified falling outside the prRI, exceeding the RCV interval, RV25 or CP5, we searched for records identifying the presence of tumour at 3 and 12 months after the test. The sensitivity, specificity and predictive power of each strategy were calculated. RESULTS: PrRI approaches derived using CVI-EU, and both limits of reference interval achieve the best sensitivity (87.5 %) and NPV (99.3 %) at 3 and 12 months of all evaluated criteria. Only 3 results per patients are enough to calculate prRIs that reach this diagnostic performance. CONCLUSIONS: PrRI approaches could be an effective tool to rule out new oncological findings during the active surveillance of patients.

Haematology and plasma biochemistry reference intervals of Española, San Cristobal and Eastern Santa Cruz Galapagos tortoise species.

Normal reference intervals (RI) of hematologic and biochemical parameters are important for assessing and monitoring the health status of captive and free-living chelonians; however, such information is not available for most wildlife species. Giant Galapagos tortoises are one of the most iconic animals on earth and health information can make an important contribution to their conservation and management. This study provides formal RI of haematology and plasma biochemistry parameters and describes cell morphology along with morphometrics of free-living Eastern Santa Cruz (Chelonoidis donfaustoi), Española (Chelonoidis hoodensis) and San Cristóbal tortoises (Chelonoidis chathamensis). We explored differences in blood parameters between sexes, across the tortoise species in this study and with previously published RI of the Western Santa Cruz tortoise (Chelonoidis porteri). Biochemistry parameters of both Santa Cruz species were overall more similar to each other than to Española and San Cristobal tortoises. This research constitutes the first RI for these three Galapagos tortoise species and may be of value for advising captive-breeding and conservation plans. We recommend further research to establish RI in additional tortoise species so we may better understand and interpret haematology and biochemistry parameters as a valuable conservation tool for species of this critically endangered taxon.

Retrospective analysis of reference intervals for dried blood spot based ms/ms newborn screening programs in Chinese preterm neonates: a nationwide study.

OBJECTIVES: Although recent discoveries regarding the biomarkers of newborn screening (NBS) programs by tandem mass spectrometry (MS/MS) highlight the critical need to establish reference intervals (RIs) specifically for preterm infants, no such RIs has been formally published yet. This study addressed the gap by offering a comprehensive set of reference intervals (RIs) for preterm neonates, and illustrating the dynamic changes of each biomarker with age. DESIGN AND METHODS: The NBS data of 199,693 preterm newborns (< 37 weeks of gestation) who met the inclusion and exclusion criteria from the NNSCP database were included in study analysis. The birth weight stratified dynamic trend of each biomarker were captured by their concentrations over age. Reference partitions were determined by the method of Harris and Boyd. RIs, corresponding to the 2.5th and 97.5th percentiles, as well as the 0.5th, 25th, 50th, 75th and 99.5th percentiles were calculated using a non-parametric rank approach. RESULTS: Increasing birth weight is associated with an elevation in the levels of arginine, citrulline, glycine, leucine and isobarics, methionine, ornithine, phenylalanine, and valine, whereas the levels of alanine, proline and tyrosine decrease. Additionally, two short-chain acylcarnitines (butyrylcarnitine + isobutyrylcarnitine and isovalerylcarnitine + methylbutyrylcarnitine) and a median-chain acylcarnitine (octenoylcarnitine) decrease, while four long-chain acylcarnitines (tetradecanoylcarnitine, palmitoylcarnitine, palmitoleylcarnitine and oleoylcarnitine) increase with increasing birth weight. Age impacts the levels of all MS/MS NBS biomarkers, while sex only affects the level of malonylcarnitine + 3-hydroxybutyrylcarnitine (C3-DC + C4-OH) in very low birth weight preterm neonates. CONCLUSION: The current study developed reference intervals (RIs) specific to birth weight, age, and/or sex for 35 MS/MS biomarkers, which can help in the timely evaluation of the health and disease of preterm neonates.

Coagulation Profile of the Healthy Miranda's Donkey.

Miranda's donkey, originating in northern Portugal, is an autochthonous breed that is deeply intertwined with the region's culture and economy. Knowledge of the physiological characteristics of the breed is important for its preservation, and several studies have been carried out, but none have focused on its coagulation profile. The aim of this study was to establish reference intervals (RIs) for coagulation in healthy Miranda's donkey and to assess the influence of sex and age. Blood samples from 75 clinically healthy animals were analyzed for seven coagulation parameters: four using IDEXX ProCyte Dx and three using Start® 4-Diagnostica-Stago. The RI values were calculated following the ASVCP guidelines and with the Reference Advisor V.2.1 software. To analyze the influence of sex and age, SPSS version 29 was used. No significant differences were found between sexes (p > 0.05), but statistically significant differences were found between ages (p < 0.05) for platelet count and plateletcrit (both higher in young animals). The RIs described here can help monitor health and guide the diagnosis and treatment of diseased Miranda's donkeys, contributing to their preservation. Our study encourages further research on coagulation in donkeys and the use of different methodologies to obtain information for veterinarians working with this species.

Specific reference interval for high-sensitivity cardiac troponin I among healthy children in Wuhan, China.

Background: Troponin (Tn) is of an important biomarker for the diagnosis and prognosis of myocardial injury and for evaluating the severity of cardiac involvement due to other systemic diseases in children. Unfortunately, high-sensitivity cardiac troponin I (hs-cTnI) specific reference intervals (RIs) are extremely limited. This study aimed to establish a preliminary pediatric hs-cTnI RI for newborns, children, and adolescents in Wuhan, China. Methods: A total of 1,355 healthy participants (1 day to 19 years) were recruited from a cross-sectional study implemented in Wuhan Children's Hospital from September 2022 to August 2023. Serum hs-cTnI levels were detected via the Mindray automated chemiluminescence immunoassay analyzer (CL-6000i). Specific serum hs-cTnI RIs were established according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. The RIs were defined by the nonparametric median (P50), and 2.5th, 97.5th [P50 (P2.5-P97.5)] intervals. Results: Of the 1,355 pediatric participants, serum hs-cTnI concentrations of 1,332 children were measured. The serum overall P50 and 95% interval range (P2.5-P97.5) of serum hs-cTnI was 0.41 (0.00, 44.31) ng/L. This was higher in males of 0.47 (0.00, 44.90) ng/L than in females of 0.36 (0.00, 44.17) ng/L (P<0.01). Age- and sex-specific differences in hs-cTnI levels were observed. The levels were highly variable in children under 1 year of age (especially in newborns), deriving a P50 (P2.5-P97.5) of 22.06 (1.04, 154.22) ng/L, and gradually narrowed and decreased with increasing age, with a markedly lower established P50 (P2.5-P97.5) of 0.36 (0.00, 2.16) ng/L. However, the levels began to increase slightly at the age of 9-12 years and reached a small peak at the age range of 15 to 18 years in males with 0.71 (0.03, 3.29) ng/L, while females were less affected by puberty. Sex- and age-specific RIs for hs-cTnI were established: 5 age-specific RIs in males, 1 day-1 month: 30.16 (8.67, 171.81) ng/L; >1-12 months: 13.20 (0.63, 61.91) ng/L; >1-15 years: 0.36 (0.00, 1.86) ng/L; >15-18 years: 0.71 (0.03, 3.29) ng/L; >18-19 years: 0.52 (0.00, 1.92) ng/L; and 4 age-specific RIs in females, 1 day-1 month: 43.93 (18.82, 146.38) ng/L; >1-12 months: 5.22 (0.92, 42.54) ng/L; >1-6 years: 0.54 (0.00, 2.74) ng/L; >6-19 years: 0.23 (0.00, 1.56) ng/L. Conclusions: This study preliminarily established age- and sex-specific serum hs-cTnI RIs using the Mindray CL-6000i system in healthy children in Wuhan, China.

Reference intervals for serum immunoglobulins G, M and E levels in Brazilian children aged 1 to 10 years: a population-based study

Abstract Objective: To determine the reference intervals (RI) for serum levels of IgG, IgM, and IgE in healthy children aged 1-10 years living in central Brazil. Method: A sample of 1743 healthy children was randomly selected from kindergartens and public schools. Reference intervals were defined by non-parametric rank (Clinical Laboratory Standards Institute, USA), bootstrapping, and Horn's robust methods. Results: By the rank method, the IgG RI was 792-1771 mg/dL for children of both sexes aged 1-10 years. IgM RI were different for gender and age groups, being 45-196 mg/dL and 34-190 mg/dL for boys aged 1-2 years and 3-10 years, respectively. For girls, the IgM RI were 50-212 mg/dL and 39-212 mg/dL, for ages 1-4 and 5-10 years, respectively. The IgE RI for both sexes and ages 1-10 years was 6-1005 mg/dL. The bootstrap method showed RI similar to the rank method but with slightly different confidence intervals. Horn's robust method determined RI different from those obtained by previous methods. Conclusion: RI for serum concentrations of IgG, IgM, and IgE were established for Brazilian children aged 1-10 years. This definition will be useful for Brazilian physicians, who will have more adequate parameters for their clinical decision-making.

Effects of sodium intake, age, gender, blood sampling time on distribution of plasma aldosterone, renin activity, deoxycorticosterone, cortisol, cortisone, and 24 h urinary aldosterone levels in normotensive individuals based on LC-MS/MS.

PURPOSE: This study aims to analyze the distribution of plasma aldosterone, renin activity, deoxycorticosterone (DOC), cortisol, cortisone, and 24 h urinary aldosterone (24 h-uAld) levels based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. MATERIALS AND METHODS: Plasma and 24 h urine were collected from 129 healthy volunteers in Northeast China. The effect of sodium intake, age, gender, blood sampling time on plasma aldosterone concentration (PAC), plasma renin activity (PRA), PAC to PRA ratio (ARR), DOC, cortisol, cortisone, cortisol to cortisone ratio, and 24 h-uAld were investigated by nonparametric test, multiple linear regression and Harris-Boyd's standard deviate test. RESULTS: There was no significant difference observed in 24 h-uAld, PAC (AM), PRA(AM), ARR (AM), DOC (AM), cortisol (AM), cortisone (AM), and cortisol to cortisone (AM) between high and low sodium intake group. Significant differences were observed between morning and afternoon sampling groups in terms of PAC, ARR, DOC, cortisol, and cortisone. Reference intervals (RIs) of 24 h-uAld, PAC (AM) were recommended to be partitioned by gender. RI of PRA was recommended age stratification. CONCLUSION: We recommend that the same reference interval could be used regardless of sodium intake. Gender is the main influence factor for 24 h-uAld, PAC, and ARR. Age is key influence factor for PRA.