Calculated Reference Intervals Research Articles

B-278 Evaluation of serum copper, zinc and selenium reference intervals using The National Health and Nutrition Examination Survey (NHANES) data

Abstract Background Serum copper, zinc and selenium, are commonly ordered for assessment of nutrient status or investigation of deficiency or overload. Review of reference intervals for these analytes is challenging as most laboratories do not have the resources to do a de novo reference interval study and many literature references are not recent. The National Health and Nutrition Examination Survey (NHANES) survey presents a unique opportunity to access a comprehensive database that includes biochemical parameters and health information in order to review reference intervals regularly, especially for more esoteric tests such as trace elements. In this study, copper, zinc and selenium reference intervals were calculated using NHANES data. Methods NHANES data for individuals 18 years of age and older was obtained from three releases between 2012-2016. Copper, selenium and zinc 95% confidence intervals were evaluated by age, sex and body mass index (BMI) partitions using quantile regression. All calculations were performed in R using the quantreg package. Results The calculated reference intervals for serum copper, zinc and selenium are shown in Table 1. Serum copper had the largest changes observed between sexes, with females having a much wider reference interval on the high end. Oral contraceptive use is known to increase serum copper levels which likely explains this trend. BMI over 30 also increased the serum copper reference interval, more clearly in women than in men. Zinc reference intervals were more aligned between women and men, with slightly higher intervals observed in men. BMI did not have much effect in either sex. For selenium, men had slightly higher reference intervals than women. Conclusions NHANES data provides a comprehensive data set for reference interval evaluation, especially for more esoteric analytes such as trace elements.

Calculation of continuous reference intervals for biological parameters exhibiting strong age-dependent level changes: Its application to glycosaminoglycans and sialic acid in urine.

Glycosaminoglycan (GAG) and sialic acid (total and free) assays are used as first-line screening tests for the diagnosis of mucopolysaccharidoses and glycoproteinoses, respectively. There is a pronounced age-dependent variation in the urinary concentrations of these metabolites in the normal population, and the stratification of the reference values into discrete age ranges may lead to an undesirably high number of false-positive or false-negative results. The aim of this study was to design a method for calculating continuous reference intervals as a function of age and its application to the analysis of GAGs and sialic acid (total, free, and conjugated) in urine. In the postpubertal period, concentrations of urinary GAGs and sialic acid have reached a plateau, so a traditional calculation of the reference range in this specific age group was considered appropriate. In the prepubertal period, a nonlinear regression performed with the Excel add-in Solver was used to fit the logarithmized concentrations of the controls to a curve that represents the mean values as a function of age. A uniform distribution of the residuals was obtained, which allowed the calculation of the reference intervals by adding the values of their 2.5 and 97.5 percentiles to the independent variable of the regression curve to calculate the upper and lower reference curves. The main advantages of the developed method are (1) a reduction in the number of control samples needed to obtain adequate reference intervals and (2) an improvement in the reliability of diagnostic screening by reducing the uncertainty generated by the gaps in the traditional age-stratified method.

Reference Intervals of Mass Coefficients and Absolute Weights of Mini Pigs’ Organs

Introduction. Measurement of weights and calculation of mass coefficients of the laboratory animals’ internal organs are the integral stages of toxicological research. However, the absence of the correct intra-laboratory reference intervals corresponding to the normal values established for the animal population of a research laboratory could hinder the analysis of the mass coefficient changes in the experiment. For example, the data on weights and mass coefficients of mini pigs’ organs is being an issue due to its insufficient availability in the open sources. At the same time, in the literature there is a lot of such kind of data referring to the industrial pig breeds. Due to the wide use of the mini pigs in the pre-clinical research and because in the pig species taxonomy they are considered to be a weight category representing the pigs with reduced mass of the body with similar morphology of the organs and body systems, we have set an objective to determine and calculate the reference intervals of mass coefficients of internal organs relative to the mass of the body and brain, as well as the absolute weights of mini pigs’ internal organs and compare the results with the data on mini and industrial pig breeds in the literature sources.Materials and Methods. The data on 29 males and 29 females of the Vietnamese lop-bellied mini pig breed aged 6 months and older, who used to be in control groups of the various experiments held at JSC “SPA “House of Pharmacy” (Leningrad region) in the period from January 2018 to March 2024, was used to calculate the reference intervals. The statistical analysis was peRussian Federationormed using Microsoft Excel and Reference Value Advisor v2.1 software in compliance with the CLSI guidelines. Calculation of the reference intervals for all parameters was carried out by a robust method, the compliance with the normal distribution law was determined by Anderson–Darling test, in case of abnormal distribution of data, calculation of the reference interval was carried out with the Box–Cox transformation.Results. The data on the absolute weights of organs and their coefficients relative to the body and brain masses were presented in the form of the lower and upper reference limits and confidence intervals for each of the limit. The reference intervals of masses of organs across all parameters in males and females had similar limits, the most comparable values were found for the heart and brain parameters. The calculated interval of the heart absolute weight in males was 28.3–253 g, that of the brain was 46.5–93.7 g; in females these intervals were 42.9–279 g and 55.5–81.8 g respectively. Upon comparing the obtained data with the literature sources, it was found that the majority of the absolute weights of all measured mini pigs’ organs had fitted in the limits of the reference values, whereas the masses of the lungs and liver were at the lower limit or below the calculated intervals. The values of the absolute weights of most of the organs of the industrial pig breeds were higher than that of mini pigs, which was due to the difference in the body size and mass of the studied animal breeds. When comparing the mass coefficients of organs in relation to the body mass, it was found that the coefficients of most organs of the industrial breeds and mini pigs, on the contrary, were within the calculated reference intervals or slightly exceeded them.Discussion and conclusion. The calculated reference intervals of the mass coefficients of some organs in relation to the body mass, as well as the absolute weights of the spleen in mini pigs are comparable with the data available in literature for the industrial meat pig breeds. At the same time, the data available in the literature sources on the absolute weights of organs and their mass coefficients relative to the body mass of mini pigs, in most cases, have fitted into the calculated intervals. To increase the prognostic value of the obtained reference intervals, the analysis of a larger size sample is necessary.

Calculation of a Reference Interval for Rectal Temperature in Adult Dogs Presenting for Veterinary Care Using an Algorithm for Mixed Data.

Veterinarians rely on the measurement of canine body temperature to define the health status of dogs, but no studies exist defining a reference range for rectal temperature on a large group of dogs. The aim of this study was to define the rectal body temperature of dogs based on a large data set of diseased and healthy animals and to evaluate the capability of the employed algorithm to calculate reference intervals of numerical clinical data. Out of 24,013 recorded measurements, statistical analysis was applied to data from 9782 adult dogs that underwent clinical examination at a university clinic between 2008 and 2017. The reference interval was calculated using an algorithm developed by the Deutsche Gesellschaft für Klinische Chemie und Laboratoriumsmedizin e.V. as part of its Reference Limit Estimator software (version 1.40.36.07). The following values were excluded: multiple measurements in a given dog, samples without assigned age or dogs younger than one year, and values <30.0 °C and >43.0 °C. Out of 9782 adult dogs, 665 temperature measurements were identified as outliers, and 9117 were used for further statistical analysis. The mean rectal temperature was 38.6 °C (90% CI: 38.6-38.6 °C) with a reference interval of 37.7 °C (90% CI: 37.7-37.7 °C) to 39.5 °C (90% CI: 39.5-39.5 °C). Validation according to CLSI guidelines showed the results to be valid. The determination of a reference interval for rectal temperatures in dogs using an algorithm for mixed datasets yielded results comparable to the existing reference intervals. This demonstrates that the calculation of reference intervals from mixed datasets of clinical numerical data can be used to confirm existing reference intervals or establish such de novo.

Calculation of reference intervals for the concentrations of α-tocopherol and retinol in serum using indirect data-mining procedures

BackgroundEstablishing adequate reference intervals (RIs) for vitamins A and E is essential for diagnosing and preventing deficiencies. Due to the current boom in data mining and its easy applicability, more laboratories are establishing RIs using indirect methods. Our study aims to obtain RIs using four indirect data-mining procedures (Bhattacharya, Hoffmann, Kosmic, and RefineR) for vitamins A and E. Material and methods8943 individuals were collected to establish the RIs. After using different data cleaning steps and checking whether these data should be divided according to age and gender based on multiple linear regression and variance component analyses, indirect RIs were calculated using specific Excel spreadsheets or R-packages software. ResultsA total of 2004 records were eligible. For vitamin A, the RIs obtained were (1.11 − 2.68) µmol/L, (1.13 − 2.70) µmol/L, (1.13 − 2.71) µmol/L, and (1.17 − 2.66) µmol/L using the Bhattacharya, Hoffmann, Kosmic and RefineR approaches, respectively. For vitamin E, these intervals were (17.3 − 49.9) µmol/L (Bhattacharya), (17.3 − 48.9) µmol/L (Hoffmann), (19.6 − 50.3) µmol/L (Kosmic), and (19.4 − 50.9) µmol/L (RefineR). In all cases, the RIs were comparable. ConclusionsSuitable RIs for vitamins A and E were calculated using four indirect methods that are suitable and adapted to our population’s demographic characteristics.

Direct and indirect reference intervals of 25-hydroxyvitamin D: it is not a real vitamin D deficiency pandemic.

Many studies report vitamin D (25-OH-D) deficiency, although there is no consensus among scientific societies on cut-offs and reference intervals (RI). The aim of this study is to establish and compare RI for serum 25-OH-D by direct and indirect methods. Two studies were performed in Zaragoza (Spain). A retrospective study (N = 7222) between January 2017 and April 2019 was used for RI calculation by indirect method and a prospective study (N = 312) with healthy volunteers recruited in August 2019 and February 2020 for direct method. Seasonal differences were investigated. Measurements were performed on Cobas C8000 (Roche-Diagnostics, Basel, Switzerland) using electrochemiluminescence immunoassay technology. Reference intervals (2.5-97.5 percentile and corresponding 95% confidence intervals, CIs) were as follows: by indirect method 5.6 ng/mL (5.4 to 5.8) - 57.2 ng/mL (55.2 to 59.8), in winter 5.4 ng/mL (5.2 to 5.7) - 55.7 ng/mL (53.6 to 58.4), while in summer 5.9 ng/mL (5.4 to 6.2) - 59.9 ng/mL (56.3 to 62.9). By direct method 9.0 ng/mL (5.7 to 9.5) - 41.4 ng/mL (37.6 to 48.0), in winter 7.4 ng/mL (3.9 to 8.6) - 34.6 ng/mL (30.6 to 51.5), while in summer 13.3 ng/mL (10.1 to 14.1) - 44.1 ng/mL (38.9 to 66.0). In both methods, RIs were higher in summer. A significant difference was observed in 25-OH-D median values between the two methods (P < 0.001). Reference interval calculation according to the studied area may be a useful tool to adapt the deficiency cut-offs for 25-OH-D. Our data support 25-OH-D values over 12.0 ng/mL for healthy population as sufficient, therefore current recommendations should be updated. In addition, differences in seasonality should be taken into account.

Calculation of reference intervals for thyroid hormones using an indirect approach

Calculation of reference intervals for thyroid hormones using an indirect approach

Calculation of reference intervals for indicators of thyroid hormones and cortisol in horses

The article discusses the results of calculating reference intervals for thyroid hor mones and cortisol in adult horses. The study included the results of a laboratory study of the concentrations of total triiodothyronine, total and free thyroxine and cortisol from 50 horses aged 3 to 29 years, including 17 mares, 13 stallions and 20 geldings. All animals underwent an extensive biochemical blood test, the results of which revealed no pathological changes.To calculate the normative limits of fluctuations for each hormone, calculations were carried out using the Tukey method, which is used to determine the reference limits in the case of a small number of variants in the group and the absence of a normal distribution. Microsoft Excel was used for calculations. The conducted studies made it possible to clarify the reference intervals for thyroid hormones and cortisol in horses, which were: total triiodothyronine (T3) - 1.13-4.04 nmol/l, total thyroxine (T4) - 20.97-57.42 nmol/l, free thyroxine (fT4) 7.38-23.07 pmol/l, cortisol – 39.42-227.02 nmol/l. The results obtained can be recommended for use not only for the clinical and biochemical laboratory of St. Petersburg State University of Medicine, but also for all veterinary laboratories using diagnostic test systems for enzyme immunoassay of Vital Development Corporation.

Вариабельность биохимических показателей крови и установление референтных интервалов в доклинических исследованиях. Сообщение 12: обыкновенные игрунки

The common marmosets (Callithrix jacchus) is currently widely used in preclinical studies. These animals are used in preclinical studies aimed at studying pathological conditions associated with the central nervous system, the immune response, the study of infectious and viral diseases, as well as metabolic disorders. The wide involvement of common marmosets in preclinical studies indicates the need for control and periodic monitoring of health. The aim of this study was to establish reference intervals of biochemical blood parameters of healthy mature common marmosets, which can be used as the basic values of animals in preclinical studies. The data obtained from 24 males and 24 females were analyzed. The age of males and females of common marmosets was 12 months, the average body weight was 350 g. Determination of biochemical parameters of all animals was carried out under the same conditions using generally accepted analytical methods. For the study, blood was used, which was taken from the lateral vena of the hind paw of animals. The following parameters were recorded in the blood serum of animals: creatinine, urea, alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, cholesterol, triglycerides, total protein, albumin, glucose, creatine kinase, lactate dehydrogenase and total bilirubin. The obtained values were analyzed with other reference intervals found in the scientific literature. In general, the ranges of the conside­red indicators of both males and females were similar, but there were also differences. Thus, the upper limits of the calculated reference intervals of urea, aspartate aminotransferase, alanine aminotransferase, total bilirubin, creatine kinase and triglycerides were lower than similar literary values. According to such obtained ranges of values as total protein, albumin, glucose and lactate dehydrogenase, both similar and higher literary values were found. Differences in the obtained intervals of normal values with similar ranges from other publications may be associated with preanalytical, analytical and postanalytical features of the formulation of the analysis. Seasonality, conditions of keeping and nutrition of the marmosets are also important factors. That is why a serious aspect in preclinical research is the creation of reference intervals of healthy laboratory animals in each scientific center. The obtained intervals can help to avoid erroneous conclusions in the course of studying the safety of new therapeutic agents or modeling a pathological state.

Ferritin Reference Ranges in an Adult Population of Working-Age Adults without Anemia

Introduction Considerable controversy has surrounded the creation of reference intervals for ferritin within tested populations. This is particularly true for women and has been attributed to a high prevalence of nonanemic iron deficiency due to physiologic blood loss during menses and physiologic iron transfer during pregnancy. The Quest Blueprint for Wellness (BFW) program is an annual health screening that provides a range of testing to Quest employees and families. Using deidentified data on 24,812 individuals (55% female; age range 18-80 years old) collected as part of this program, we studied the relationship between serum ferritin and characteristics of the study population, red blood cell parameters, and iron saturation in order to better define normal reference ranges for serum ferritin. Methods Test results of participants in the annual BFW screening program conducted between January 2022 and May 2023 were identified (26,535 [53% female]); tests included hematocrit, hemoglobin, RBC indices (including RDW), total serum iron and total iron binding capacity and CRP. Individuals with abnormalities of hemoglobin, hematocrit or RBC indices (including RDW); serum iron or serum TIBC; or elevated CRP were successively excluded, leaving 24,812 participants (55% female). None of these remaining individuals had a personal history of anemia or an identified ICD-10 code associated with anemia or other RBC disorder. This study population was used in subsequent analyses. Multimodal decomposition (MMD) in R (version 4.2.2) was used to calculate reference intervals based on the distribution of results associated with the healthy study subpopulation that was defined. To address the possibility that the TIBC saturation initially employed (20%) was too low, reference intervals were also determined when varying TIBC saturations from 20%-25%. Results As shown in Table 1, the lower limits of the ranges identified did not vary significantly as the TIBC saturation percent was increased from 20% to 25%. The lower limit for women below 50 years of age ranged from 11-13 ng/mL, which was substantially lower than the lower limits for men of the same age. Over the age of 50, the lower limit of the ferritin reference ranges for women increased, approaching but not equaling or exceeding the values observed for men until ages greater than 70. This may reflect the end of menses and the gradual repletion of iron stores. In contrast, the lower limits of the reference ranges for serum ferritin for men increased at ages 30-40 and then declined and fell below that of women in the eighth decade. Conclusions Comparing the lower range of ferritin values between men and women, these data suggest that iron deficiency may be present in a large proportion of working age women in the absence of anemia or abnormal RBC indices. These data also suggest that normal ferritin values are age dependent for both men and women. These conclusions are tempered by the unavailability of a physiologic reference standard able to demonstrate that iron deficiency is in fact present. The lower limit of the ferritin range for women under the age of 60 and for men over the age of 70 approximates the ferritin values associated with the absence of stainable bone marrow iron. While this test is the traditional “gold standard” it is rarely performed for the evaluation of iron status. The evaluation of iron deficiency at present lacks a physiologic indicator, analogous to the relationship between parathyroid hormone and calcium levels which permitted the definition of blood levels of 25 hydroxyvitamin D that represented sufficiency, or methylmalonic acid concentration in B12 deficiency. The broader availability of measures to assess the functional status of reticuloendothelial iron stores available to support erythropoiesis, such as measurements of hepcidin, would facilitate such an assessment.

The effects of sex, season, and natural sunlight on plasma vitamin D3 levels in two chelonian species (Testudo hermanni, Trachemys scripta) and their interaction with calcium, phosphate, and magnesium as associated plasma compounds

Species specific physiology, seasonal changes, sex, and husbandry factors all influence the blood chemistry of chelonians, including vitamin D3, calcium, phosphate and magnesium levels. Problems in the supply of many of these are commonly seen in captive reptiles. The goal of this study was to measure vitamin D3, calcium, phosphate and magnesium in plasma from captive, healthy, adult Hermann’s tortoises (Testudo hermanni) and pond sliders (Trachemys scripta). Samples were categorized and compared based on species, sex, season, and access to sunlight as a central husbandry element. Blood samples of 522 Hermann’s tortoises and 188 pond sliders, taken from March to September 2022, were included in the study. New reference intervals for vitamin D3, calcium, phosphate and magnesium were established, with specific reference intervals calculated for each species, sex, and season in those cases in which significant differences were found based on these factors. For the calculation of reference intervals for vitamin D3 the factors species, season and access to sunlight were considered. Vitamin D3 levels differed by access to sunlight in some seasons depending on the species and were generally higher in Hermann’s tortoises. Plasma vitamin D3 levels did not correlate with calcium, phosphorus or magnesium levels on a larger scale in either species. Calcium, phosphate, and magnesium were higher in females than in males of both species, and magnesium was higher in Hermann’s tortoises than in pond sliders. Our results can be helpful in a more specific interpretation of blood results and support previous findings that direct sunlight is an important factor in chelonian health. More studies are needed to better understand the role of other hormonal influence on the vitamin D3, calcium, phosphate and magnesium metabolism in chelonians.

Референтные интервалы массовых коэффициентов внутренних органов морских свинок

In toxicological studies for the detection of target organs, organ mass coefficients and absolute organ weights of laboratory animals are one of the monitored parameters. The aim of this study is to determine reference intervals of organ mass coefficients in relation to body weight and brain weight, and absolute organ weights in guinea pigs. The indirect method of obtaining reference values was used to determine reference intervals, and data from 40 male and 61 female outbred guinea pigs obtained during animal health monitoring from 2021 to 2023 were included in the analysis. The initial step in obtaining reference intervals is to determine the presence of statistical outliers and their exclusion, for each parameter evaluated separately. Reference intervals were established based on Clinical and Laboratory Standards Institute recommendations for mass coefficient and absolute values of heart, lung, thymus, liver, spleen, kidney, adrenal glands, brain, testes, and ovaries. Due to the small number of reference values (less than 120), a robust method of calculating reference intervals with confidence intervals was used. To improve the prognostic significance of the obtained reference intervals, it is necessary to increase the size of the analysed sample of reference values (more than 120). From the perspective of bioethical norms, a retrospective approach to obtaining additional reference values should be used to achieve this goal.

Reference intervals for reticulocyte indices, immature reticulocyte fraction, and the percentage of hypochromic red blood cells in adult large breed dogs using the ADVIA 2120 hematology analyzer.

Reticulocyte indices are used to characterize anemia, including the identification of regeneration. In people, the immature reticulocyte fraction (IRF), percentage of hypochromic red blood cells (%HYPO-RBC), and other reticulocyte indices have been used as earlier indicators of erythropoiesis and as valuable monitoring tools in the assessment of various therapies. The reference intervals (RI) of the IRF and %HYPO-RBC have not been reported in dogs. The objective of this study was to establish RIs for novel variables (IRF, %HYPO-RBC, and CH-delta) and assess RIs for more commonly reported reticulocyte indices in healthy dogs. RIs were calculated from blood results retrospectively collected from 106 client-owned healthy dogs at the time of induction into a blood donor program using the ADVIA 2120 hematology analyzer (Siemens Healthcare Diagnostics). For the calculation of RIs, appropriate tests were applied for outlier detection and normality assessment. For variables normally distributed, RIs and their respective 90% confidence intervals (CIs) were calculated using parametric methods, while for variables not normally distributed, robust methods were used and bootstrapping for calculating the 90% CIs. The following RIs were established: reticulocyte hemoglobin content (CHr) 24.5-28 pg, mean reticulocyte volume (MCVr) 85.9-99.3 fL, mean corpuscular hemoglobin concentration of reticulocytes (CHCMr) 271.0-306.3 g/L, IRF 10.4%-43.5%, CH-delta 0.5-4.3 pg, and percentage of hypochromic red blood cells (%HYPO-RBC) 0.10%-0.80%. The results of this study provide RIs for novel reticulocyte variables. Further studies are required to determine the clinical utility of IRF, %HYPO-RBC, and CH delta as early indicators of erythropoietic activity in canine patients.

NT-proBNP Reference Intervals in Healthy U.S. Children, Adolescents, and Adults.

N-terminal pro-B-type natriuretic peptide (NT-proBNP) is a cardiac biomarker used in the clinical management of heart failure. We sought to create updated reference intervals for NT-proBNP for healthy US children, adolescents, and adults. We identified a population of healthy individuals using the 1999 to 2004 cycles of the National Health and Nutrition Examination Survey (NHANES). We measured serum NT-proBNP in 12 346 adults and 15 752 children and adolescents with the Elecsys NT-proBNP assay on the Roche e601 autoanalyzer. We compared 4 methods for reference interval calculation, and presented the final reference intervals using the robust method partitioned by age and sex categories. NT-proBNP values were available for 1949 healthy adults and 5250 healthy children and adolescents. NT-proBNP concentrations in males and females varied according to age, being higher in early childhood, relatively lower in late adolescence, and highest through middle age and older age. Females tended to have higher NT-proBNP concentrations compared to men from late adolescence until middle age. The upper reference limit, or 97.5th percentile, for 50 to 59 year-old men was 225 ng/L (90% CI: 158 to 236), and for 50 to 59 year-old women, 292 ng/L (90% CI: 242 to 348). Among healthy individuals, NT-proBNP concentrations varied greatly according age and sex. The reference intervals presented here should inform future clinical decision limits and suggest that age- and sex-specific intervals may be necessary to more precisely characterize risk.

Hematology, Biochemistry, and Protein Electrophoresis Reference Intervals of Western European Hedgehog (Erinaceus europaeus) from a Rehabilitation Center in Northern Portugal

The Western European hedgehog (Erinaceus europaeus) can work as a bioindicator of environmental pollution and be a host for multiple zoonotic agents, making it relevant in terms of One Health studies. It is essential to deepen the knowledge on this species and calculate reference intervals (RIs) for the usual hematological and biochemical parameters. For this retrospective study (2017-2022), the archives of the Clinical Pathology Laboratory (LPC) of University of Trás-os-Montes and Alto Douro (UTAD) Veterinary Teaching Hospital were analyzed. Data of hematology, clinical biochemistry, and protein electrophoresis from 37 healthy hedgehogs of the Wild Animal Rehabilitation Center at UTAD, Northern Portugal, were included. It was possible to calculate RIs for almost all of the variables in the study, using Reference Value Advisor V2.1. Moreover, sex and age effects were investigated: alkaline phosphatase (p = 0.012, higher in males); total proteins (p = 0.034, higher in adults); mean cell volume (p = 0.007) and mean corpuscular hemoglobin (p = 0.010) (both higher in juveniles); and red blood cell distribution width (p = 0.021, higher in adults). Our study allowed for the first time to define RIs for a population of hedgehogs in Portugal, having a potentially relevant impact on species conservation and in the human-animal health interface.

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.

Reference intervals for thyroid disorders calculated by indirect method and comparison with reference change values.

The aim of the study was to calculate reference intervals (RIs) for thyroid stimulating hormone (TSH), free thyroxine (fT4) and free triiodothyronine (fT3) and evaluate the clinical significance of these intervals by use of reference change values (RCV) of the analytes. Laboratory patient data between August and December 2021 were evaluated for the study. A total of 188,912 patients with TSH, fT4, fT3, anti-thyroid peroxidase antibodies (Anti-TPO) and anti-thyroglobulin antibodies (Anti-Tg) results were evaluated. All measurements were performed on Cobas c801 (Roche Diagnostics, Penzberg, Germany) using electrochemiluminescence immunoassay technology. Estimated RIs were compared with manufacturer's by means of RCVs of analytes. Thyroid stimulating hormone values didn't differ significantly by gender and age. The combined RIs for whole group (N = 28,437) was found as 0.41-4.37 mIU/mL. Free T4 values (11.6-20.1 pmol/L, N = 13,479 in male; 10.5-19.5 pmol/L, N = 17,634 female) and fT3 values (3.38-6.35 pmol/L, N = 2,516 in male; 3.39-5.99 pmol/L, N = 3,348 pmol/L in female) significantly differed by gender (P < 0.050). Both fT4 and fT3 values also showed significant differences in age subgroups comparisons. So, male and female RIs were represented separately for age subgroups. When compared with manufacturer's RIs, TSH whole group and fT4 subgroups RIs didn't exceed the analytes' RCVs, but this difference was greater for fT3. Reference interval estimation by use of indirect method out of laboratory data may be more accurate than manufacturer provided RIs. This population based RIs evaluated using RCV of analytes may provide useful information in clinical interpretation of laboratory results.

Harmonization of indirect reference intervals calculation by the Bhattacharya method.

The aim of this study was to harmonize the criteria for the Bhattacharya indirect method Microsoft Excel Spreadsheet for reference intervals calculation to reduce between-user variability and use these criteria to calculate and evaluate reference intervals for eight analytes in two different years. Anonymized laboratory test results from outpatients were extracted from January 1st 2018 to December 31st 2019. To assure data quality, we examined the monthly results from an external quality control program. Reference intervals were determined by the Bhattacharya method with the St Vincent's hospital Spreadsheet firstly using original criteria and then using additional harmonized criteria defined in this study. Consensus reference intervals using the additional harmonized criteria were calculated as the mean of four users' lower and upper reference interval results. To further test the operation criteria and robustness of the obtained reference intervals, an external user validated the Spreadsheet procedure. The extracted test results for all selected laboratory tests fulfilled the quality criteria and were included in the present study. Differences between users in calculated reference intervals were frequent when using the Spreadsheet. Therefore, additional criteria for the Spreadsheet were proposed and applied by independent users, such as: to set central bin as the mean of all the data, bin size as small as possible, at least three consecutive bins and a high proportion of bins within the curve. The proposed criteria contributed to the harmonization of reference interval calculation between users of the Bhattacharya indirect method Spreadsheet.

Value Ranges and Clinical Comparisons of Serum DHEA-S, IL-6, and TNF-α in Western Lowland Gorillas.

Simple SummaryBiomarkers are molecules found in the body that can indicate current physiological functioning and are frequently used to monitor health and diagnose disease. These biomarkers, such as hormones and immune markers, can provide valuable information on the health and welfare of animals. Knowledge on the normal levels of these biomarkers in various species is a crucial step for monitoring health and understanding disease. In this paper, we report assays and value ranges of biomarkers rarely measured in western lowland gorillas in human care. We also compare concentrations of each biomarker between clinical and non-clinical samples. The levels of the two immune biomarkers were higher in clinical samples, but the levels of the neuroendocrine biomarker were not significantly different between clinical and non-clinical samples. These data contribute toward eventually establishing reference ranges for these biomarkers and help improve our understanding of health and welfare in zoo-housed animals.Physiological data can provide valuable information about the health and welfare of animals. Unfortunately, few validated assays and a lack of information on species-typical levels of circulating biomarkers for wildlife make the measurement, interpretation, and practical application of such data difficult. We validated commercially available kits and calculated reference intervals (herein called “value ranges”) for dehydroepiandrosterone-sulfate (DHEA-S), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) in a sample of zoo-housed western lowland gorillas due to the roles these biomarkers play in stress and immune responses. For each biomarker, we present species-specific value ranges for a sample of gorillas in human care (n = 57). DHEA-S did not vary significantly by sex or age, while IL-6 was higher in males and older gorillas and TNF-α was higher in females but not associated with age. We also compared non-clinical with clinical samples (n = 21) to explore whether these biomarkers reflect changes in health status. There was no significant difference between clinical and non-clinical samples for DHEA-S, but both IL-6 and TNF-α were significantly higher in gorillas showing clinical symptoms or prior to death. Additional work is needed to improve our understanding of normal versus clinical variation in these biomarkers, and we encourage continued efforts to identify and validate additional biomarkers that can be used to inform assessments of health and welfare in wildlife.

Indirect determination of biochemistry reference intervals using outpatient data.

The aim of this study was to determine reference intervals in an outpatient population from Vall d’Hebron laboratory using an indirect approach previously described in a Dutch population (NUMBER project). We used anonymized test results from individuals visiting general practitioners and analysed during 2018. Analytical quality was assured by EQA performance, daily average monitoring and by assessing longitudinal accuracy between 2018 and 2020 (using trueness verifiers from Dutch EQA). Per test, outliers by biochemically related tests were excluded, data were transformed to a normal distribution (if necessary) and means and standard deviations were calculated, stratified by age and sex. In addition, the reference limit estimator method was also used to calculate reference intervals using the same dataset. Finally, for standardized tests reference intervals obtained were compared with the published NUMBER results. Reference intervals were calculated using data from 509,408 clinical requests. For biochemical tests following a normal distribution, similar reference intervals were found between Vall d’Hebron and the Dutch study. For creatinine and urea, reference intervals increased with age in both populations. The upper limits of Gamma-glutamyl transferase were markedly higher in the Dutch study compared to Vall d’Hebron results. Creatine kinase and uric acid reference intervals were higher in both populations compared to conventional reference intervals. Medical test results following a normal distribution showed comparable and consistent reference intervals between studies. Therefore a simple indirect method is a feasible and cost-efficient approach for calculating reference intervals. Yet, for generating standardized calculated reference intervals that are traceable to higher order materials and methods, efforts should also focus on test standardization and bias assessment using commutable trueness verifiers.