Gender-specific Reference Intervals Research Articles

Pediatric reference intervals for serum folate and cobalamin based on a European population without exposure to folic acid fortification

The aim of the present study was to define pediatric reference intervals for serum cobalamin and folate utilizing data generated from a population not exposed to food fortified with folic acid. Folate and cobalamin results analyzed by electrochemiluminescence immunoassay (Roche Cobas) were obtained from 2375 children (2 months to 17.99 years of age). The serum samples were collected between 2011 and 2015 as part of the LIFE (Leipzig Research Centre for Civilization Diseases) Child cohort study in Germany, where folic acid fortification of food is not mandated. These results were used to generate age- and gender-specific reference intervals presented as non-parametric 2.5 and 97.5 percentiles. Because of a subsequent restandardisation of the Roche folate assay in 2016, folate values were recalculated accordingly for adaptation to results obtained using the present calibration. In both genders, folate concentrations decreased continuously with age, whereas cobalamin concentrations peaked at five years of age and then declined. Teenage females had higher concentrations of cobalamin in the age group 12–17.99 years.

Age-, season- and gender-specific reference intervals of serum 25-hydroxyvitamin D3 for healthy children (0 ~ 18 years old) in Nanning area of China

Establishing specific reference intervals (RIs) of serum 25-hydroxyvitamin D3 [25(OH)D] for children is essential for improving the accuracy of diagnosis and prognosis monitoring of diseases such as rickets and growth retardation. The study including 6,627 healthy children was conducted to establish specific RIs of 25(OH)D for children in Nanning area of China. The results showed that there were statistically significant differences among age, season, and gender of serum 25(OH)D levels, and the age-specific RIs of serum 25(OH)D were 20.3 ~ 53.6 ng/mL for 0 ~ ≤ 1 year and 18.9 ~ 49.6 ng/mL for 2 ~ ≤ 3 years. The age-, season-specific RIs of serum 25(OH)D for 4 ~ ≤ 6 years in spring–summer and autumn–winter were 15.8 ~ 42.6 ng/mL and 15.2 ~ 37.7 ng/mL, respectively. The age-, gender-specific RIs of serum 25(OH)D for 7 ~ ≤ 18 years for males and females were 12.1 ~ 36.1 ng/mL and 10.8 ~ 35.3 ng/mL, respectively. This study successfully established the RIs of serum 25(OH)D, which may help to improve disease diagnosis and monitoring for children in the Nanning area of China.

Age- and Gender-Specific Reference Intervals for the Fasting Serum Lipid Levels in a Pediatric Population Aged 0-＜15 Years in Nanjing, China.

The lipid reference intervals (RIs) that are currently used for children in China are not based on studies of the local population and normally do not consider age or gender differences. This study aimed to establish age- and sex-specific RIs for the fasting serum lipid levels in the pediatric population aged 0 - 15 years in Nanjing, China. 5,866 children aged 3 days to ＜15 years were recruited to establish serum lipid RIs, and the triglyceride (TG), total cholesterol (TC), and high-density lipoprotein cholesterol (HDL-C) levels were analyzed using the Roche cobas702 automatic biochemical analyzer. Low-density lipoprotein cholesterol (LDL-C) and non-high-density lipoprotein cholesterol (nHDL-C) levels were calculated (LDL-C=TC-HDL-C-TG/5, and nHDL-C=TC-HDL-C). Smoothed percentile curves for the boys and girls were generated using the LMS method. Age- and sex-specific RIs were the determined according to the methods recommended by the Clinical and Laboratory Standards Institute EP28-A3c guidelines. This study showed that the serum lipid levels varied considerably throughout childhood and adolescence, with sex differences, especially in infants aged less than 2 years and puberty. Based on the Harris-Boyd method, sex partitions were required for ages ＜6 months in the TC indicator and for ages ≤ 28 days in LDL-C and nHDL-C. Age partitions were also required for all serum lipid parameters. We established age- and sex-specific RIs for TG, TC, HDL-C, LDL-C, and nHDL-C parameters in children aged 0 days to ＜15 years in Nanjing, China. These data are thus considered to be useful for the screening of dyslipidemia in children and adolescents.

Age-and Gender-Specific Reference Intervals for Systemic Inflammatory Indicators in Healthy Moroccan Adults.

Neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR) and the systemic immune inflammation index (SII) are effective prognostic markers of patients in various clinical situations such as cancer, cardiovascular diseases and inflammatory diseases. This study aims to explore the reference values based on gender and age for NLR, PLR, LMR and SII in the Moroccan population. From January 2018 to February 2020, data of ostensibly healthy adults were collected retrospectively from the laboratory information system (LIS) of the Laboratory for Research and Medical Analysis of the Fraternal Royal Gendarmerie, Rabat (Morocco). A total of 5,898 men and 10,172 women aged between 18 and 90 years were included. RIs of each parameter were established and validated in accordance with the Clinical and Laboratory Standards Institute (CLSI) document C28-A3. NLR was significantly different between men and women (p < 0.05), while PLR, LMR and SII were not. The values of NLR, PLR, LMR and SII differed significantly between different age groups of both genders (p < 0.05). Therefore, RI of PLR, LMR, and SII had to be divided into groups based on age, but not on gender, while establishing the NLR reference intervals took into account both factors; age and gender. This paper provides Reference Intervals for NLR, PLR, LMR, and SII according to age and gender in healthy Moroccan adults. This can improve assessment and potentially widen the use of these biomarkers in Moroccan clinical context.

Establishment of age- and -gender specific reference intervals for amino acids and acylcarnitines by tandem mass spectrometry in Turkish paediatric population.

We determined age- and gender-specific reference intervals (RIs) for acylcarnitines and amino acids by tandem mass spectrometry (MS/MS) in the Turkish paediatric population by using laboratory information system (LIS) data. A total of 9156 MS/MS results of children between 0-18 years of age, were downloaded from the LIS. Premature infants and newborns followed in the intensive care unit were excluded and only the first result of each patient attending outpatient clinics was included. Children with a known or suspected diagnosis of metabolic disease, malignancy, epilepsy, mental retardation, or genetic disorder were excluded. Laboratory results were evaluated and children with any pathological laboratory finding were excluded, resulting in a final sample size of 3357 (2029 boys and 1328 girls). Blood was collected by capillary puncture and spotted on Whatman 903 filter paper cards and analysed by MS/MS (Shimadzu LCMS-8050, Shimadzu Corporation, Kyoto, Japan). Data were evaluated for age and gender differences and age partitioning was performed according to the literature and visual evaluation of the data. Age subgroups were: ≤ 1 month, 2 months-1 year, 2-5 years, 6-10 years, and 11-18 years. There were significant age-related differences for the majority of amino acids and acylcarnitines thus age dependent RIs were established. Gender-specific RIs were established for tyrosine, leucine-isoleucine, isovalerylcarnitine (C5) and hexadecanoylcarnitine (C16). Establishing age-related RIs can enhance the quality of medical care by facilitating early diagnosis and therapy, especially in certain metabolic disorders presenting with mild biochemical abnormalities and subtle clinical manifestations.

Current practice and recommendations for managing transgender patient data in clinical laboratories in the United Kingdom and Republic of Ireland.

Transgender people may avoid seeking medical care due to previous negative experiences and fear of discrimination. Clinical laboratories can contribute to a poor patient experience and clinical outcome when the design and functionality of laboratory information management systems (LIMS) do not consider the needs of transgender patients. This survey aimed to capture current practices in United Kingdom and Republic of Ireland clinical laboratories concerning how transgender patient data and test requests are managed throughout the total testing process. An anonymous survey was distributed to clinical laboratory professionals in November 2021. Thirty-three questions covered how gender variables are recorded for transgender patients and used to inform gender-specific calculations, test access, and reference intervals (RIs). Of the 66 respondents, 70% were based in laboratories in England, with a majority of laboratories having ISO 15189 accreditation and processing 1000-10,000 blood samples daily. Eighty-five percent stated that their LIMS had a single field recording sex or gender information. Forty-three percent did not limit test access based on gender, but 68% did not append RIs for patients with unknown or indeterminate gender. This survey was the first to quantify how clinical laboratories manage sex and gender information and report results for transgender and non-binary patients, and details several key recommendations based on the survey responses.

Reference Intervals for Plasma Free Kappa and Lambda Chains and Kappa/Lambda Ratio using PENIA.

Determination of free light chains is used increasingly for patients with multiple myeloma and other plasma cell dyscrasias. The aim of the present study was to define reference intervals for free kappa and lambda chains and kappa/lambda ratio in lithium heparin plasma and compare the test results with cystatin C based estimated glomerular filtration rate. Free kappa and lambda chains were measured in Liheparin plasma from 222 healthy blood donors using free light chain reagents and a BNII nephelometer from Siemens Diagnostics. Calculated reference intervals for kappa chain, free was 4.73 mg/L (90% confidence interval 4.00 - 5.45) - 22.66 mg/L (20.33 - 24.98), for lambda chain, free was 4.33 mg/L (3.70 - 4.95) - 29.28 mg/L (26.96 - 31.59), and for Kappa/Lambda Chain ratio 0.59 (0.56 - 0.62) - 1.46 (1.37 - 1.56). There was no need for gender or age specific reference intervals. Cystatin C based estimated glomerular filtration rate had a significant effect on the levels of free light chains. The study presents reference intervals for plasma free light chains and compared results of estimated glomerular filtration rate with free light chains of kappa and lambda.

Age and gender-specific reference intervals for a panel of lysophosphatidylcholines estimated by tandem mass spectrometry in dried blood spots

Background and objectivesVery long-chain fatty acyl-lysophosphatidylcholines (VLCFA-LysoPCs) are measured in dried blood spots (DBS) for identifying X-linked adrenoleukodystrophy (X-ALD) and other inherited peroxisomal disorders. Our study aimed to establish age- and gender-specific reference intervals for a panel of LysoPCs measured by tandem mass spectrometry in DBS. MethodsLysoPCs (26:0-, 24:0-, 22:0- and 20:0-LysoPCs) were estimated by flow injection analysis-tandem mass spectrometry (FIA-MS/MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods in 3.2 mm blood spots of 2689 anonymized, putative normal subjects (1375 males, and 1314 females) aged between 2 days and 65 years. Samples were divided into groups: Neonates (0–1month), Infants (>1m-1year), Children and Adolescents (>1–18years), and Adults (>18years). Reference intervals were determined using the percentile approach and represented as the median with the 1st and 99th percentile lower and upper limits. ResultsThe percentage coefficient of variation (CV) for repeatability assays of internal and external quality control samples were within acceptable limits. Significant differences (P <0.0001, P <0.01) were observed in the concentrations of 26:0-, 24:0-, 22:0- and 20:0-LysoPCs and their ratios, 26:0/22:0-, 24:0/22:0-, 26:0/20:0-and 24:0/20:0-LysoPC in neonates and infants when compared to children, adolescents, and adults. Levels of 26:0-, 24:0- and 22:0-LysoPCs decreased, whereas 20:0-LysoPC increased with age. There were no significant gender-based differences in the concentration of LysoPCs. ConclusionWe established age- and gender-specific reference intervals for a panel of LysoPCs in DBS. These reference values would be helpful when interpreting LysoPC values in DBS during screening for X-ALD and other peroxisomal disorders.

New reference intervals for endocrinological biomarkers in pediatric patients: what can we learn from the LIFE child study?

Abstract Objectives We established reference intervals for serum concentrations of hormones from healthy pediatric subjects and investigated their associations with gender, body mass index (BMI), puberty and oral contraceptives (oC). Methods We calculated reference intervals for the thyroid parameters thyroid-stimulating hormone (TSH), free triiodothyronine (FT3), free thyroxine (FT4), and calcitonin (Ct); the bone markers osteocalcin, procolagen type 1 N-propeptide, and carboxy-terminal cross-linking telopeptide of type 1 collagen; the calciotropic hormones 25-hydroxyvitamin D (25(OH)D) and parathyroid hormone and the steroids cortisol, progesterone, 17-hydroxyprogesterone, androstenedione, testosterone, estradiol, dehydroepiandrosterone sulfate and aldosterone. Up to 10,002 blood serum samples from 3,229 healthy children and adolescents (age interval: 3 months to 20 years) were measured. To investigate the associations between the hormone levels with age, sex, weight status and the role of puberty-based changes, the measurement and BMI values were transformed into standard deviation scores. Results Most of the hormones depended on age- and gender. Puberty was linked to a, in part, temporary decrease in TSH, FT3 (for females), FT4, Ct, cortisol (for girls) and aldosterone (for boys) and peak in the bone marker and calciotropic hormones (excluding 25(OH)D) and nearly all remaining steroids. BMI had effects on the thyroid, bone, and calciotropic parameters, whereas oC led to increased cortisol, suppressed progesterone and estradiol values. Conclusions Age- and gender-specific reference intervals are essential for the interpretation of pediatric patients’ hormone measurements. Influencing factors as puberty, BMI, or oC should be taken into consideration for diagnosis and treatment monitoring.

Age and Gender-Specific Reference Intervals for Uric Acid Level in Children Aged 5-14 Years in Southeast Zhejiang Province of China: Hyperuricemia in Children May Need Redefinition.

Context: Hyperuricemia is defined when the plasma uric acid concentration is above 416 μmol/L (7 mg/dl) in male adults, or 357 μmol/L (6 mg/dl) in female adults. However, there are no explicit criteria yet for children.Objective: It is necessary to set up reference intervals for the uric acid level in different age groups among children.Materials and Methods: A total of 5,439 individuals (3,258 males, 2,181 females) were included in the final statistical analysis. Reference values of all age groups were determined by statistical descriptions. Multiple linear regression analysis was applied to determine the relationship between uric acid level, BMI, and age.Results: The level of uric acid increased with age. Gender differences in uric acid level occurred after the onset of puberty. Additionally, linear regression revealed a positive correlation between the uric acid level and BMI.Discussion and Conclusion: The reference range of the uric acid level in children is inconsistent with the previous viewpoint. Body mass index plays an important role in uric acid metabolism.

Gender-specific reference intervals for serum prolactin concentrations before and after precipitation by polyethylene glycol

Prolactin, a hormone secreted by the anterior pituitary, exists in three major forms in circulation. The macroprolactin form is biologically inactive but contributes to elevated serum prolactin concentrations. Precipitation of macroprolactin by polyethylene glycol (PEG) is widely used in clinical laboratories for the screening of macroprolactin. The aim of this study was two-fold. Firstly, we sought to establish locally relevant reference intervals for serum prolactin and post-PEG precipitation prolactin concentrations in both genders on the Roche Cobas Prolactin II electrochemiluminescence immunoassay. Secondly, the prolactin concentrations after precipitation by PEG dissolved in phosphate-buffered saline (post-PEG(PBS)) were compared with those after precipitation by PEG dissolved in deionised water (PEG(diH2O)). Prolactin concentrations were measured by using the Prolactin Gen II assay on a Roche Cobas e601 analyser. Recoveries of prolactin after precipitation by PEG in PBS and PEG in diH2O were 64.7%–115.8% and 60.9–100.8%, respectively. Post-PEG (PBS) prolactin concentrations were not statistically different from post-PEG (diH2O) prolactin concentrations in either gender.

Establishment of reference intervals of monomeric prolactin to identify macroprolactinemia in Chinese patients with increased total prolactin

BackgroundMacroprolactin is responsible for pseudohyperprolactinemia and is a common pitfall of the prolactin immunoassay. We aimed to determine the frequency of macroprolactinemia in Chinese hyperprolactinemic patients using monomeric prolactin discriminated by precipitation with polyethylene glycol (PEG).MethodsPost-PEG monomeric prolactin gender-specific reference intervals were established for the Elecsys immunoassay method (Roche Diagnostics) using sera from healthy female (n = 120) and male (n = 120) donors. The reference intervals were validated using 20 macroprolactinemic (as assessed by gel filtration chromatography (GFC)) sera samples, and presence of monomeric prolactin was discriminated by GFC. Patients with high total prolactin were then screened by PEG precipitation to analyze macroprolactin. The demographic and biochemical details of patients with true hyperprolactinemia and macroprolactinemia were compared.ResultsReference intervals for monomeric prolactin in females and males were 3.4–18.5 and 2.7–13.1 ng/mL, respectively. Among 1140 hyperprolactinemic patients, macroprolactinemia was identified in 261 (22.9 %) patients while the other 879 (77.1 %) patients were diagnosed with true hyperprolactinemia. Menstrual disturbances were the most common clinical feature in both groups. Galactorrhea, amenorrhea, and visual disturbances occurred more frequently in true hyperprolactinemic patients (P < 0.05).ConclusionsThe prevalence of macroprolactin in Chinese patients with hyperprolactinemia was described for the first time. Monomeric prolactin concentration, along with a reference interval screening with PEG precipitation, provides a diagnostic approach for hyperprolactinemia with improved accuracy.

Establishment of the reference intervals of lymphocyte subsets for healthy Chinese Han adults and its influencing factors.

BackgroundCellular immune monitoring is becoming more critical in the clinic, but its application has not yet become sufficiently widespread. One reason may be the different reference intervals among clinical laboratories due to several factors. Percentage and number of lymphocyte subsets are standard indicators of cellular immune detection. The present study aimed to establish standardized reference intervals of lymphocyte subsets in the healthy Chinese Han adult population and examine such influencing factors as age, gender, region, and measurement instruments.MethodsA total of 496 healthy Chinese Han people aged 18–59 years from 3 China Mainland regions (north, east, and south) were enrolled. The sample of each center was simultaneously examined by three flow cytometers (FACSCantoTMII, FACSLyricTM, and FACSCaliburTM). A single-platform flow cytometry-based absolute count technique was used to quantify the percentage and number of each lymphocyte subset. The flow cytometry results were analyzed by variance analysis and Z test to determine the influence of age, gender, and instruments on lymphocyte subsets.ResultsMulti-center, age-specific, and gender-specific reference intervals of healthy Chinese Han adults’ lymphocyte subsets were established. There was no statistical difference in the results from the three flow cytometers. Gender affected the results of CD4+ (%) and the absolute count of CD3−CD16+CD56+, where CD4+ (%) was higher in women, and the absolute count of CD3−CD16+CD56+ was higher in men. Age mainly affected the CD4+/CD8+ ratio, which was statistically higher in groups aged over 40 years; the percentage and number of CD3−CD19+ were more elevated in age groups below 30 years; however, the difference was not statistically significant.ConclusionsThis study established the reference intervals of lymphocyte subsets for healthy Chinese Han adult populations under the standardized methods. This study was the first nationwide study in China to use a flow cytometry-based single-platform method to establish the reference intervals of lymphocyte subsets of the healthy Chinese Han adult population. Gender and age were shown to influence the results of lymphocyte subsets.

Indirect reference intervals for haematological parameters in capillary blood of pre-school children.

IntroductionIndirect estimation of reference intervals (RIs) is straightforward and inexpensive procedure for determination of intra-laboratory RIs. We applied the indirect approach to assess RIs for haematological parameters in capillary blood of pre-school children, using results stored in our laboratory database.Materials and methodsWe extracted data from laboratory information system, for the results obtained by automatic haematology analyser in capillary blood of 154 boys and 146 girls during pre-school medical examination. Data distribution was tested, and logarithmic transformation was applied if needed. Reference intervals were calculated by the nonparametric percentile method.ResultsReference intervals were calculated for: RBC count (4.2-5.4 x1012/L), haemoglobin (114-146 g/L), MCH (25.0-29.4 pg), MCHC (321-368 g/L), RDW-SD (36.1-43.5 fL), WBC count (4.5-12.3 x109/L), neutrophils count (1.7-6.9 x109/L) and percentage (29.0-69.0%), lymphocytes count (1.6-4.4 x109/L) and percentage (21.9-60.7%), PLT (165-459 x109/L), MPV (8.1-11.4 fL) and PDW (9.2-14.4%). Gender specific RIs were calculated for monocytes count (male (M): 0.2-1.6 x109/L; female (F): 0.1-1.4 x109/L) and percentage (M: 2.5-18.3%; F: 1.8-16.7%), haematocrit (M: 0.34-0.42 L/L; F: 0.34-0.43 L/L), MCV (M: 73.4-84.6 fL; F: 75.5-84.2 fL) and RDW (M: 12.1-14.3%; F: 11.7-13.9%), due to observed gender differences in these parameters (P = 0.031, 0.028, 0.020, 0.012 and 0.001; respectively). Estimated RIs markedly varied from the literature based RIs that are used in the laboratory.ConclusionsIndirect method employed in this study enables straightforward assessment of RIs in pre-school children. Herein derived RIs differed from the literature-based ones, indicating the need for intra-laboratory determination of RIs for specific populations and sample types.

Sources of variation and establishment of Russian reference intervals for major hormones and tumor markers

A multicenter study was organized to explore sources of variation (SVs) of reference values (RVs) for 22 major immunochemistry analytes and to determine reference intervals (RIs) for the Russian population. According to IFCC Committee on Reference Intervals and Decision Limits (C-RIDL) protocol, 758 healthy volunteers were recruited in St. Petersburg, Moscow, and Yekaterinburg. Serum samples were tested for five tumor markers, 17 hormones and related tests by Beckman Coulter's UniCel DxI 800 immunochemistry analyzer. SVs were explored using multiple regression analysis and ANOVA. Standard deviation ratio (SDR) of 0.4 was used as primary guide for partitioning RIs by gender and age. SDR for between-city difference was <0.4 for all analytes. Secondary exclusion of individuals was done under the following conditions: for female sex-hormones, those with contraceptives (8%); for CA19-9, those supposed to have negative Lewis blood-group (10.5% males and 11.3% females); for insulin, those with BMI≥28 kg/m2 (31%); for the thyroid panel, those with anti-thyroid antibodies (10.3% males; 24.5% females), for CEA those with smoking habit (30% males and 16% females). Gender-specific RIs were required for all analytes except CA19-9, CA15-3, thyroid-related tests, parathyroid hormone, and insulin. Age-specific RIs were required for alpha-fetoprotein, CEA, all sex-hormones for females, FSH and progesterone for both sexes. RIs were generally derived by parametric method after Gaussian transformation using modified Box-Cox formula. Exceptions were growth hormone, estradiol for females in postmenopause, and progesterone for females in premenopause, for which nonparametric method was required due to bimodal distribution and/or insufficient detection limit. RIs for major hormones and tumor markers specific for the Russian population were derived based on the up-to-date internationally harmonized protocol by careful consideration of analyte-specific SVs.

Establishment of gender specific reference intervals for hepatic enzymes: A pilot study

Reference interval is the common tools used for interpreting various biochemical parameters. The age, gender, diet, ethnicity, socioeconomic conditions affect the physiology of population and thereby affecting the reference intervals. Thus, it is needed to set up our own reference intervals which are specific to particular gender, region and population.To establish the gender specific reference interval for hepatic enzymes at BIMS Hospital, Belagavi.This was a hospital based cross-sectional study involving 450 subjects. The selected subjects were from the general population, health professionals, medical students and those attending the Out-Patient Department (OPD) for general health check ups. The serum Alanine transaminase (ALT), serum Aspartate transaminase (AST), serum Alkaline phosphatase (ALP) were estimated based on the recommendations of IFCC without pyridoxal phosphate and serum Gamma glutamyl transferase (GGT) by enzymatic colorimetric method. The 97.5 percentile and 2.5 percentile was used to obtain the reference intervals.The serum AST and serum GGT showed the statistically significant difference between the male and female values. Thus separate reference should be considered for both males and females. There was no statistically significant difference in serum ALT and serum ALP levels. Thus generalized reference intervals were established.The study revealed the difference in reference intervals of serum AST and serum GGT between males and females.

Longitudinal changes in the dental arches and soft tissue profile of untreated subjects with normal occlusion.

AimThe aim of this study was to analyze dental and soft tissue profile development in children with normal occlusions to establish age- and gender-specific reference intervals for German children during their active growth period.Subjects and methodsThe study group consisted of a sample of 31 untreated Caucasian subjects with normal occlusions. Dental casts were analyzed at four different stages of dentitional development. Extraoral profile photographs were available for 19 subjects at stages T2–T4. In these subjects 11 angular measurements and 14 indices were analyzed. Statistical comparisons of gender-specific differences were performed by Mann–Whitney U tests (p ≤ 0.05).ResultsUpper and lower posterior and total arch perimeters were recorded to be significantly larger in male subjects until the late mixed dentition. Subsequently, there was a tendency toward larger dimensions in males for those parameters. Upper and lower intercanine, interpremolar and intermolar widths were significantly larger in males throughout the entire observation period. There were no statistically significant gender differences with regard to most angular measurements in the dental arches, including molar rotation, palatal volume, overbite, overjet and molar relationship at later dental stages.ConclusionIn untreated subjects with normal occlusion, dental arch and soft tissue parameters can be considered age-dependent. For some dental parameters, gender-specific differences were found that should be taken into consideration during diagnosis and treatment planning of growing children. The obtained longitudinal data of untreated children provide useful information for orthodontic diagnosis, treatment planning and future research projects.

Stability and reference intervals of spot urinary fractionated metanephrines and methoxytyramine by tandem mass spectrometry as a screening method for pheochromocytoma and paraganglioma.

The 24 h urinary-fractionated metanephrine (MN) and normetanephrine (NMN) are recommended as the preferred indicators for laboratory diagnosis of pheochromocytoma and paraganglioma (PPGL). However, it might cause missed diagnosis for some type of PPGL, in addition, 24-h urine collection is inconvenient and prone to error, so we aimed to develop a better screening method. Urine samples from patients of primary hypertension (n = 317) or PPGL (n = 64) were collected randomly and in a 24-h cycle. Samples were prepared by solid phase extraction (SPE) and analyzed with LC-MS/MS. Sample stability under different storage conditions was investigated. The gender-specific reference intervals of spot urinary catecholamine metabolites adjusted by creatinine were established and the diagnostic performance was evaluated. Urinary MN, NMN (MNs), and 3-methoxytyramine (3-MT) were stable at room temperature or 4 °C for at least 4 days without adding any preservatives and at -20 °C for at least 11 weeks. Reference intervals of spot urinary MN, NMN and 3-MT adjusted by creatinine were 20.2-174.0, 47.6-452.0, and 20.6-398.5 µg/g for male and were 15.3-202.0, 34.4-461.0, and 38.0-392.6 µg/g for female. The sensitivity and specificity of spot urinary MN, NMN, and 3-MT were similar with that of 24-h urine (P > 0.05). Regardless of urine sample type, combined application of MNs or MNs and 3-MT can improve the diagnosis efficiency of MN and 3-MT alone. Adding 3-MT to diagnosis model can improve diagnostic sensitivity to some extent, and the analysis of spot urinary MNs and 3-MT can provide reliable diagnostic information in a much shorter diagnostic time, it may reduce the medical expenses indirectly.

Bone formation and resorption markers at 7 years of age: Relations with growth and bone mineralization.

PurposeWe aimed to describe bone formation and resorption markers in generally healthy prepubertal children using total alkaline phosphatase (tALP), osteocalcin (OC) and β-isomerized C-terminal telopeptides of type I collagen (β-CTx) serum concentrations and to estimate markers’ correlations with anthropometric growth (height, weight, body mass index and trajectories of weight gain) as well as bone mineral content (BMC) and areal density (aBMD).MethodsWe assessed 395 7-year-old children from the Generation XXI cohort with tALP, OC and β-CTx concentrations determined from a fasting venous blood sample and BMC/aBMD measured by dual-energy X-ray absorptiometry. Gender-specific reference intervals for tALP, OC and β-CTx in 7-year-old children were established by calculating the 2.5th and 97.5th percentiles. Pearson and partial correlation coefficients (controlling for sex, age, body size and season) between bone markers and growth measures were computed.ResultstALP increased with height (rpartial controlled for sex = 0.26, 95%CI: 0.17, 0.35), was higher in overweight than in healthy weight children, and in children who gained weight above average during infancy. No correlations were found between OC or β-CTx and growth. In girls, OC was slightly correlated with subtotal BMC (rpartial = 0.22, 95%CI: 0.08, 0.35), subtotal aBMD (rpartial = 0.20, 95%CI: 0.06, 0.33) and lumbar spine aBMD (rpartial = 0.23, 95%CI: 0.09, 0.36). tALP and β-CTx were not correlated with any of the DXA-derived bone measures.ConclusionThis study contributed to the description of bone turnover at 7 years of age and suggested that bone metabolism markers measured in a single point in time have limited ability to describe anthropometric growth and overall bone status in generally healthy prepubertal children.

Age-specific and sex-specific reference intervals for non-fasting lipids and apolipoproteins in 7260 healthy Chinese children and adolescents measured with an Olympus AU5400 analyser: a cross-sectional study

AimsEthnic, demographic, lifestyle, genetic and environmental factors influence lipids and apolipoproteins. The aim of this study was to establish age-specific and gender-specific reference intervals for non-fasting lipids and apolipoproteins in...