Type 2 cytokines and scleroderma interstitial lung disease

Interstitial lung disease (ILD) is a life-threatening complication of systemic sclerosis (SSc). Type 2 (Th2) cytokines play a pivotal role in airway disease. Study aim was to evaluate serum level of Th2 interleukin (IL) and chemokine in SSc-ILD. Serum levels of IL-4, IL-5, IL-11, IL-13, IL-21, IL-31 and CXCL-13 were measured by Bio-Plex Multiplex Immunoassays in 60 SSc patients and 20 healthy controls (HC). Pulmonary function tests with diffusion lung capacity for carbon monoxide (DLco) and high resolution computed tomography (HRCT) were performed in SSc patients. ILD is defined as fibrotic changes (ground glass, reticular and honeycombing), assessed by Computer-Aided Lung Informatics for Pathology Evaluation and Ratings (CALIPER) software, affecting at least 10% of the lungs. Serum levels of Th2 cytokines were higher in SSc patients than HC. A linear correlation was observed between ground glass and IL-13 (r = 0.342, p < 0.01), IL-21 (r = 0.345, p < 0.01), IL-31 (r = 0.473, p < 0.001), IL-4 (r = 0.863, p < 0.001), IL-5 (r = 0.249, p < 0.05) and peripheral blood eosinophils (r = 0.463, p < 0.001). We found a negative correlation between DLco and IL-4 (r =  - 0.511, p < 0.001) and peripheral blood eosinophils (r =  - 0.446, p < 0.001). In the logistic regression analysis, IL-4 is associated with DLco ≤ 60% of the predicted [OR 1.039 (CI 95%: 1.015-1.064), p < 0.001], whilst mRSS [OR 1.138 (CI 95%: 1.023-1.266), p < 0.05] and IL-4 [OR 1.017 (CI 95%: 1-1.034), p < 0.05] were associated with ILD. Th2 inflammation could play a key role in early phase of SSc-ILD.

The effect of CALIPER-derived parameters for idiopathic pulmonary fibrosis in predicting prognosis, progression, and mortality: a systematic review

BACKGROUND

High-resolution computed tomography (HRCT), as the main tool for monitoring idiopathic pulmonary fibrosis (IPF), is characterized by subjective variability among radiologists and insensitivity to subtle changes. Recently, a few studies have aimed to decrease subjective bias by assessing the severity of IPF using computer software, i.e., Computer-Aided Lung Informatics for Pathology Evaluation and Rating (CALIPER). However, these studies had diverse research directions. In this review, we systematically assess the effect of CALIPER in the management of IPF.

METHODS

A systematic review was conducted through a search of published studies in PubMed, Web of Science, Cochrane, Embase, Scopus, and CNKI databases from database inception through February 28, 2022. The methodological quality would be evaluated by using Methodological Index for Non-Randomized Studies (MINORS). Narrative synthesis summarized findings by participant characteristics, study design, and associations with outcomes.

RESULTS

Ten studies were included. They evaluated the relationship between CALIPER-derived parameters and pulmonary function test (PFT) and mortality. CALIPER-derived parameters showed a significant correlation with PFT and mortality. Two studies reported that CALIPER could be used to stratify outcomes.

CONCLUSION

CALIPER-derived parameters can be used to evaluate prognosis and mortality. CALIPER-derived parameters combined with composite physiologic index (CPI) or Gender-Age-Physiology (GAP) could help clinicians implement targeted management by refining prognostic stratification. However, research has been constrained by small number of retrospective investigations and sample sizes. Therefore, it is essential to design prospective controlled studies and establish the staging system by CALIPER-derived parameters and combining them with CPI, FVC, or GAP.

CLINICAL RELEVANCE STATEMENT

It is beneficial for clinic to provide objective, sensitive, and accurate indicators of disease progression. It also helps the clinic to develop individualized treatment plans based on the stage of disease progression and provides evaluation of efficacy in drug trials.

KEY POINTS

• Computer-Aided Lung Informatics for Pathology Evaluation and Rating (CALIPER) is a quantitative CT analysis software that can be used to evaluate the progression of disease on CT. • The CALIPER-derived vessel-related structure shows great performance in the management of idiopathic pulmonary fibrosis. • CALIPER-derived parameters combined with composite physiologic index or Gender-Age-Physiology can be used to refine prognostic stratification.

Pediatric reference intervals for endocrine markers in healthy children and adolescents on the Liaison XL (DiaSorin) immunoassay system

OBJECTIVES

Prominent physiological changes occurring throughout childhood and adolescence necessitate the consideration of age and sex in biomarker interpretation. Critical gaps exist in pediatric reference intervals (RIs) for specialized endocrine markers, despite expected influence of growth and development. The current study aimed to establish and/or verify RIs for six specialized endocrine markers on a specialized immunoassay system.

METHODS

Samples were collected from healthy children and adolescents (5 to <19 years) and apparently healthy outpatients (0 to <5 years) as part of the Canadian Laboratory Initiative on Pediatric Reference Intervals (CALIPER). Serum samples were analysed for aldosterone, renin (plasma), thyroglobulin, anti-thyroglobulin, growth hormone, and insulin-like growth factor-1 (IGF-1) on the Liaison XL (DiaSorin) immunoassay platform. RIs (2.5th and 97.5th percentiles) were established for aldosterone, renin, thyroglobulin, anti-thyroglobulin, and growth hormone. Manufacturer-recommended pediatric RIs for IGF-1 were verified.

RESULTS

Age-specific RIs were established for aldosterone, renin, and thyroglobulin, while no age-specific differences were observed for anti-thyroglobulin or growth hormone. IGF-1 was the only endocrine marker studied that demonstrated significant sex-specific differences. Manufacturer-recommended IGF-1 RIs were verified for children aged 6 to <19 years, while those for children aged 0 to <6 years did not verify.

CONCLUSIONS

This study marks the first time that pediatric RIs for aldosterone and renin were established in the CALIPER cohort and highlights the dynamic changes that occur in water and sodium homeostasis during the first years of life. Overall, these data will assist pediatric clinical laboratories in test result interpretation and improve clinical decision-making for patients tested using Liaison immunoassays.

Pediatric reference interval verification for 17 specialized immunoassays and cancer markers on the Abbott Alinity i system in the CALIPER cohort of healthy children and adolescents

OBJECTIVES

Clinical laboratory investigation of autoimmune, metabolic, and oncologic disorders in children and adolescents relies on appropriateness of reference intervals (RIs). The Canadian Laboratory Initiative on Pediatric Reference Intervals (CALIPER) previously established comprehensive pediatric RIs for specialized immunoassays on the Abbott ARCHITECT system. Herein, we aim to verify performance on new Alinity i assays by evaluating sera collected from healthy children as per Clinical and Laboratory Standards Institute (CLSI) EP-28A3C guidelines.

METHODS

Precision, linearity, and method comparison experiments were completed for 17 specialized Alinity immunoassays, including cancer antigens, autoimmune peptides, and hormones. Sera collected from healthy children and adolescents (birth-18 years, n=100) were evaluated. CLSI-based verification was completed using previously established CALIPER RIs for ARCHITECT assays as the reference.

RESULTS

Of 17 specialized immunoassays assays, only anti-cyclic citrullinated peptides (anti-CCP) did not meet acceptable verification criterion (i.e., ≥90% of results within ARCHITECT reference CI). Anti-thyroglobulin, anti-thyroid peroxidase, and carcinoembryonic antigen did not require age-specific consideration beyond one year of age, with 63, 91, and 80% of samples equalling the limit of detection, respectively. Estimates were separated by sex for relevant assays (e.g., sex hormone binding globulin, total and free prostate specific antigen).

CONCLUSIONS

Findings support transferability of pediatric RIs on ARCHITECT system to the Alinity system for 16 specialized immunoassays in the CALIPER cohort and will be a useful resource for pediatric clinical laboratories using Alinity assays. Further work is needed to establish evidence-based interpretative recommendations for anti-CCP and continue to evaluate pediatric RI acceptability for newly available assay technologies.

LMS-based continuous reference percentiles for 14 laboratory parameters in the CALIPER cohort of healthy children and adolescents

OBJECTIVES

Marked physiological changes in growth and development present challenges in defining pediatric reference intervals for biomarkers of health and disease. Lambda, Mu, and Sigma (LMS)-based statistical modeling provides a continuous normal distribution by negating skewness and variation, and is commonly used to establish growth charts. Such LMS reference curves are suggested to enhance laboratory test result interpretation. The current study establishes LMS-based continuous reference percentiles for 14 biomarkers in the CALIPER cohort of healthy children and adolescents.

METHODS

Data from healthy children and adolescents aged 1-<19 years were used to establish continuous reference percentiles using a novel LMS-based statistical method, including 2.5th, 25th, 50th, 75th, and 97.5th percentiles. The LMS approach applies a Box-Cox data transformation and summarizes continuous distributions by age via three curves: skewness (Lambda), median (Mu), and coefficient of variation (Sigma).

RESULTS

LMS-based percentiles and z-scores were generated for 14 common pediatric biomarkers that demonstrate dynamic concentration patterns with age (e.g., alkaline phosphatase) and/or wherein the magnitude of difference from the population mean may be clinically relevant (e.g., triglycerides). The LMS model captured age- and sex-specific distributions accurately and was not substantially influenced by outlying points.

CONCLUSIONS

This is the first study to establish LMS-based continuous reference percentiles for biochemical markers in a healthy Canadian pediatric population. The current LMS-based approach builds upon previous continuous reference interval models by providing graded percentiles to improve test result interpretation, particularly with repeated measures over time. This method may assist in facilitating a patient-centered approach to laboratory medicine.

Pediatric Reference Intervals for Point-of-Care Random Glucose in Healthy Children and Adolescents

BACKGROUND

Glucose testing at the point-of-care (POC) is routinely used in the diagnosis, prognosis, and monitoring of diabetic states and other clinical conditions. Accurate reference intervals (RIs) are essential in appropriate clinical decision-making. In this study, RIs were established for random glucose (whole blood) in the Canadian Laboratory Initiative on Pediatric Reference (CALIPER) cohort using 2 POC instruments: the Nova Biomedical StatStrip (handheld glucometer) and Radiometer ABL90 FLEX Plus (benchtop instrument). An analytical comparison was also completed between the 2 POC systems and a laboratory-based analyzer (Ortho Vitros 5600).

METHODS

Approximately 400 healthy children and adolescents (birth to 18 years) were recruited with informed consent from community schools or clinics providing care to metabolically stable/healthy children. Random venous samples were collected and run sequentially on the Nova Biomedical StatStrip (whole blood), Radiometer ABL90 FLEX Plus (whole blood), and Ortho Vitros 5600 (serum). RIs and method comparisons between analytical platforms were completed according to CLSI guidelines.

RESULTS

Significantly different glucose concentrations were observed in infancy, requiring age-specific partitioning (0-<1 month, 1-<6 months, 6 months-<19 years) on all platforms. Excellent concordance was observed between POC platforms (Pearson r > 0.90), with a small negative bias. Good comparability was observed between POC and laboratory-based platforms (Pearson r > 0.80).

CONCLUSION

This study established comprehensive pediatric RIs for random glucose (whole blood) on modern POC systems in the CALIPER cohort for the first time. Results demonstrate excellent concordance in glucose values between POC systems and good comparability with a laboratory-based analyzer. These data will assist in more accurate clinical decision-making in pediatric healthcare institutions.

Lung vessel volume evaluated with CALIPER software is an independent predictor of mortality in COVID-19 patients: a multicentric retrospective analysis

INTRODUCTION

Computer-Aided Lung Informatics for Pathology Evaluation and Ratings (CALIPER) software has already been widely used in the evaluation of interstitial lung diseases (ILD) but has not yet been tested in patients affected by COVID-19. Our aim was to use it to describe the relationship between Coronavirus Disease 2019 (COVID-19) outcome and the CALIPER-detected pulmonary vascular-related structures (VRS).

MATERIALS AND METHODS

We performed a multicentric retrospective study enrolling 570 COVID-19 patients who performed a chest CT in emergency settings in two different institutions. Fifty-three age- and sex-matched healthy controls were also identified. Chest CTs were analyzed with CALIPER identifying the percentage of VRS over the total lung parenchyma. Patients were followed for up to 72 days recording mortality and required intensity of care.

RESULTS

There was a statistically significant difference in VRS between COVID-19-positive patients and controls (median (iqr) 4.05 (3.74) and 1.57 (0.40) respectively, p = 0.0001). VRS showed an increasing trend with the severity of care, p < 0.0001. The univariate Cox regression model showed that VRS increase is a risk factor for mortality (HR 1.17, p < 0.0001). The multivariate analysis demonstrated that VRS is an independent explanatory factor of mortality along with age (HR 1.13, p < 0.0001).

CONCLUSION

Our study suggests that VRS increases with the required intensity of care, and it is an independent explanatory factor for mortality.

KEY POINTS

• The percentage of vascular-related structure volume (VRS) in the lung is significatively increased in COVID-19 patients. • VRS showed an increasing trend with the required intensity of care, test for trend p< 0.0001. • Univariate and multivariate Cox models showed that VRS is a significant and independent explanatory factor of mortality.

Pediatric Reference Intervals for Critical Point-of-Care Whole Blood Assays in the CALIPER Cohort of Healthy Children and Adolescents

OBJECTIVES

Point-of-care testing (POCT) is being increasingly adopted to support clinical care. Data for critical care parameters in healthy children on POCT instruments are lacking. We established comprehensive reference standards for several whole blood parameters on the Radiometer ABL90 FLEX PLUS blood gas analyzer in the Canadian Laboratory Initiative on Paediatric Reference Intervals (CALIPER) cohort.

METHODS

Approximately 300 healthy children and adolescents (age range, birth to <19 years; sex, boys and girls) were recruited with informed consent. Venous whole blood was collected (using heparinized syringes) and rapidly analyzed at the point of collection for pH, Pco2, Po2, carboxyhemoglobin, methemoglobin, lactate, and electrolytes on the ABL90 FLEX PLUS instrument. Reference intervals were established according to Clinical and Laboratory Standards Institute guidelines.

RESULTS

Of the parameters assessed, 6 required age partitioning; none required sex partitioning. Reference value distributions were consistent across the pediatric age range, demonstrating higher variation in the early neonatal period.

CONCLUSIONS

This study established reference standards for 10 critical care analytes in the CALIPER cohort for the first time. These data contribute to our understanding of normative pediatric values for venous electrolytes, metabolites, and blood gases on a modern POCT instrument, facilitating test interpretation in clinical settings that use these assays.

Pediatric reference intervals for 32 routine biochemical markers using the siemens healthineers atellica® CH assays in healthy children and adolescents

BACKGROUND

Pediatric reference intervals are essential for test interpretation. With development of newer analytical systems, de novo reference interval establishment is of necessary importance. In the current study, pediatric reference intervals were determined for 32 analytes using Siemens Healthineers Atellica® CH assays in the CALIPER cohort of healthy children and adolescents.

METHODS

Approximately 600 healthy children and adolescents were recruited with informed consent and collected serum samples were analyzed on the Siemens Healthineers Atellica® CH platform. Assays studied included enzymes, proteins, lipids, electrolytes, and additional markers Reference intervals were established according to Clinical and Laboratory Standards Institute (CLSI) guidelines.

RESULTS

Of the 32 parameters, 26 required age partitioning and 18 required sex partitioning. Reference value distributions included consistent increases, decreases, and dynamic variation across the age continuum. Chloride, LDL cholesterol, glucose, lipase, sodium, and triglyceride demonstrated no age or sex-specific differences.

CONCLUSION

The current study expands the clinical utility of the CALIPER database to include 32 Siemens Atellica® chemistry assays. Reference value distributions for Siemens assays mirrored those observed on other comparable assays/systems with few exceptions (e.g. lipase, direct and total bilirubin). These finding support the robustness of previously derived reference intervals in the CALIPER cohort and other global cohorts.

Continuous reference curves for common hematology markers in the CALIPER cohort of healthy children and adolescents on the Sysmex XN-3000 system

INTRODUCTION

Clinicians and healthcare professionals rely heavily on health-associated standards, such as reference intervals (RIs), for appropriate laboratory test result interpretation. RIs are commonly partitioned into discrete age/sex bins based on statistical and/or clinical significance. In pediatric hematology, such partitioning does not adequately represent complex variation in analyte concentrations throughout maturation. The objective of this study was to establish continuous RIs for common hematological parameters in the healthy pediatric Canadian Laboratory Initiative on Pediatric Reference Intervals (CALIPER) cohort.

METHODS

Data from healthy CALIPER children and adolescents (6 months-<19 years) were used to generate continuous RIs (ie, 2.5th and 97.5th quantiles) for 19 hematological parameters. Continuous curves were statistically established with nonparametric quantile regressions. Flagging rate analysis was completed for the established continuous upper and lower reference limits and subsequently compared to previously published discrete CALIPER reference intervals for all parameters.

RESULTS

Continuous RIs were established for 19 hematology parameters, where seven required sex-specific reference curves. Based on flagging rate assessment, continuous RIs appear to more accurately estimate hematological reference limits over the pediatric age range, especially for analytes with complex age- and sex-specific reference value patterns.

CONCLUSIONS

This is the first study to generate continuous RIs for a breadth of hematological markers in a healthy pediatric Canadian population. The increased power of continuous reference intervals to accurately estimate the complex relationship between hematological analyte concentration and age during a time of extensive growth and development is expected to improve laboratory test result interpretation and, subsequently, pediatric clinical decision-making.

Pediatric reference interval verification for endocrine and fertility hormone assays on the Abbott Alinity system

OBJECTIVES

The Canadian Laboratory Initiative on Pediatric Reference Intervals (CALIPER) has developed an extensive database of reference intervals (RIs) for several biomarkers on various analytical systems. In this study, pediatric RIs were verified for key immunoassays on the Abbott Alinity system based on the analysis of healthy children samples and comparison to comprehensive RIs previously established for Abbott ARCHITECT assays.

METHODS

Analytical performance of Alinity immunoassays was first assessed. Subsequently, 100 serum samples from healthy children recruited with informed consent were analyzed for 16 Alinity immunoassays. The percentage of test results falling within published CALIPER ARCHITECT reference and confidence limits was determined. If ≥ 90% of test results fell within the confidence limits, they were considered verified based on CLSI guidelines. If <90% of test results fell within the confidence limits, additional samples were analyzed and new Alinity RIs were established.

RESULTS

Of the 16 immunoassays assessed, 13 met the criteria for verification with test results from ≥ 90% of healthy serum samples falling within the published ARCHITECT confidence limits. New CALIPER RIs were established for free thyroxine and prolactin on the Alinity system. Estradiol required special considerations in early life.

CONCLUSIONS

Our data demonstrate excellent concordance between ARCHITECT and Alinity immunoassays, as well as the robustness of previously established CALIPER RIs for most immunoassays, eliminating the need for de novo RI studies for most parameters. Availability of pediatric RIs for immunoassays on the Alinity system will assist clinical laboratories using this new platform and contribute to improved clinical decision-making.

Influence of ethnicity on biochemical markers of health and disease in the CALIPER cohort of healthy children and adolescents

Background Accurate pediatric reference intervals (RIs) for laboratory tests determined in a healthy pediatric population are essential for correct laboratory test interpretation and clinical decision-making. In pediatrics, RIs require partitioning by age and/or sex; however, the need for partitioning based on ethnicity is unclear. Here, we assessed the influence of ethnicity on biomarker concentrations in the Canadian Laboratory Initiative on Pediatric Reference Intervals (CALIPER) cohort of healthy children and adolescents and compared the results with the National Health and Nutrition Examination Survey (NHANES). Methods A total of 52 biomarkers were measured in a multiethnic population of 846-1179 healthy children (aged 5 to <19 years) upon informed consent. Biomarker concentrations were retrospectively compared between four major ethnic groups (i.e. Black, Caucasian, East Asian, and South Asian, determined by parental ethnicity). Retrospective results were verified prospectively using an additional 500 healthy pediatric samples with equal sample size across ethnicities. Ethnic-specific differences were assessed based on statistical significance and biological and analytical variations. Appropriate age-, sex-, and ethnic-specific RIs were calculated. Results Ethnic-specific differences were not observed for 34 biomarkers examined in the retrospective analysis, while 18 demonstrated statistically significant ethnic differences. Among these, seven analytes demonstrated ethnic-specific differences in the prospective analysis: vitamin D, amylase, ferritin, follicle-stimulating hormone (FSH), immunoglobulin A (IgA), immunoglobulin G (IgG), and immunoglobulin M (IgM). Analysis of select NHANES data confirmed CALIPER findings. Conclusions This is the first comprehensive Canadian pediatric study examining ethnic-specific differences in common biomarkers. While the majority of biomarkers did not require ethnic partitioning, ethnic-specific RIs were established for seven biomarkers showing marked differences. Further studies in other populations are needed to confirm our findings.

Pediatric reference interval verification for common biochemical assays on the Abbott Alinity system

OBJECTIVES

The quality of clinical laboratory service depends on quality laboratory operations and accurate test result interpretation based on reference intervals (RIs). As new analytical systems continue to be developed and improved, previously established RIs must be verified. The Canadian Laboratory Initiative on Pediatric Reference Intervals (CALIPER) has established comprehensive RIs for many biomarkers on several analytical systems. Here, published CALIPER RIs for 28 chemistry assays on the Abbott ARCHITECT were assessed for verification on the newer Alinity system.

METHODS

An analytical validation was first completed to assess assay performance. CALIPER serum samples (100) were analyzed for 28 chemistry assays on the Alinity system. The percentage of results falling within published pediatric ARCHITECT reference and confidence limits was determined for each analyte. Based on Clinical and Laboratory Standards Institute (CLSI) guidelines, if ≥90% of test results fell within confidence limits of ARCHITECT assay RIs, they were considered verified.

RESULTS

Of the 28 assays assessed, 26 met the criteria for verification. Reference values for calcium and magnesium did not meet the criteria for verification with 87% and 35% falling within previously established ARCHITECT confidence limits, respectively. However, both assays could be verified using pediatric RIs provided in the Abbott Alinity package insert.

CONCLUSIONS

In this study, CALIPER ARCHITECT RIs were verified on the Alinity system for several chemistry assays. These data demonstrate excellent concordance for most assays between the Abbott ARCHITECT and Alinity systems and will assist in the implementation of the Alinity system in pediatric healthcare institutions.

Pediatric reference intervals for endocrine markers and fertility hormones in healthy children and adolescents on the Siemens Healthineers Atellica immunoassay system

OBJECTIVES

Rapid development in childhood and adolescence combined with lack of immunoassay standardization necessitates the establishment of age-, sex-, and assay-specific reference intervals for immunochemical markers. This study established reference intervals for 11 immunoassays on the new Siemens Healthineers Atellica® IM Analyzer in the healthy CALIPER cohort.

METHODS

A total of 600 healthy participants (birth to 18 years) were recruited from the community, and serum samples were collected with informed consent. After sample analysis, age- and sex-specific differences were assessed, and outliers were removed. Reference intervals were established using the robust method (40-<120 participants) or nonparametric method (≥120 participants).

RESULTS

Of the 11 immunoassays studied, nine required age partitioning (i.e., dehydroepiandrosterone-sulfate, estradiol, ferritin, folate, follicle-stimulating hormone, luteinizing hormone, progesterone, testosterone, vitamin B12), and seven required sex partitioning. Free thyroxine and thyroid-stimulating hormone demonstrated no significant age- and/or sex-specific differences.

CONCLUSIONS

Overall, the age- and sex-specific trends observed closely mirrored those previously reported by CALIPER on other platforms as well as other internationally recognized studies. However, established lower and upper limits demonstrated some discrepancies between published values from healthy cohorts on alternate analytical systems, highlighting differences between manufacturers and the need for platform-specific reference intervals for informed pediatric clinical decision-making.

Continuous reference intervals for 19 endocrine, fertility, and immunochemical markers in the CALIPER cohort of healthy children and adolescents

BACKGROUND

Reference intervals are traditionally partitioned into discrete ranges by major covariates such as age and sex. However, discrete reference intervals often oversimplify the complex relationship between analyte concentration and age. Continuous reference intervals have been suggested to more accurately represent this complex relationship, particularly in pediatrics. The objective of this study was to establish continuous reference intervals for endocrine, fertility, and additional immunochemical parameters in the CALIPER cohort of healthy children and adolescents.

METHODS

Continuous reference intervals from 1 to 18.5 years of age were established using retrospective CALIPER data collected from healthy Canadian children and adolescents. Continuous reference intervals (2.5th and 97.5th percentiles) were determined for 19 parameters by nonparametric quantile regression. Total and yearly flagging rates were calculated for the upper and lower continuous reference limits and compared to previously published partitioned reference limits.

RESULTS

Continuous reference intervals were established for 19 endocrine, fertility, and additional immunochemical parameters, with 11 requiring sex-specific reference curves. Continuous reference intervals assessed both visually and by flagging rate analysis more accurately represented the relationship between analyte concentration and age, particularly for parameters with complex reference value patterns.

CONCLUSION

This is the first comprehensive report to establish continuous reference intervals for several immunochemical parameters including endocrine and fertility markers in a healthy paediatric Canadian cohort. The ability of continuous reference intervals to provide a better estimate of age-related changes in reference values suggest their potential to improve paediatric laboratory test result interpretation and clinical decision-making.

Complex biological patterns of hematology parameters in childhood necessitating age- and sex-specific reference intervals for evidence-based clinical interpretation

INTRODUCTION

Hematology laboratory parameters are among the most routinely ordered tests in support of adult and pediatric care. However, appropriate interpretation of test results has been a challenge in pediatrics since accurate and up-to-date reference intervals that reflect the dynamic physiological changes associated with growth and development have not been available. Critical gaps continue to exist in pediatric hematology reference intervals for modern laboratory platforms. To address this gap, this study establishes age- and sex-specific reference intervals for 25 hematology parameters in the CALIPER cohort of healthy children and adolescents using a common platform, the Sysmex XN-3000 analytical system.

METHODS

Fresh whole blood samples collected from a total of 641 healthy children and adolescents (birth to <21 years) with informed consent were analyzed for 25 hematological parameters on the Sysmex XN-3000 Hematology Analyzer. Age- and sex-specific reference standards were calculated based on Clinical and Laboratory Standards Institute guidelines.

RESULTS

Of the 25 analytes assessed, 19 required age-partitioning and seven required sex-partitioning (ie, red blood cell count, hemoglobin, hematocrit, mean corpuscular volume, red blood cell distribution width-SD, red blood cell distribution width-CV, and monocyte percentage). Age- and sex-specific differences mostly coincided with the onset of puberty.

CONCLUSION

This study establishes a comprehensive database of pediatric reference intervals for hematology parameters in the CALIPER cohort using the widely used Sysmex XN-3000 analytical platform. These data highlight the dynamic hematological profile observed in healthy children and adolescents and the need for reference interval stratification by age and sex.

CALIPER Hematology Reference Standards (I)

OBJECTIVES

Accurate hematologic test interpretation based on normative reference standards is critical to ensure appropriate clinical decision making. However, healthy pediatric reference data for most hematology parameters are lacking. To address this gap, this study establishes age- and sex-specific hematologic reference standards in the Canadian Laboratory Initiative on Pediatric Reference Intervals (CALIPER) cohort of healthy children and adolescents.

METHODS

Fresh whole blood samples collected from a total of 566 healthy children and adolescents (birth to <21 years) with informed consent were analyzed for 47 hematologic parameters on the Beckman Coulter DxH 900. Age- and sex-specific reference standards were calculated based on the Clinical and Laboratory Standards Institute guidelines.

RESULTS

Reference value distributions for most hematology parameters demonstrated dynamic changes across the pediatric age range with significant age-specific differences observed for 39 of the 47 parameters examined. Sex-specific differences were also observed for eight hematologic parameters, primarily during and after puberty.

CONCLUSIONS

This study establishes a robust database of pediatric reference standards for 47 hematologic parameters in the CALIPER cohort for the first time. These comprehensive reference value data sets report potentially important and physiologically relevant trends in hematologic markers, clearly demonstrating the need for pediatric reference standards for hematologic test interpretation.

CALIPER Hematology Reference Standards (II)

OBJECTIVES

The objective of this study was to establish comprehensive age- and sex-specific reference intervals for hematologic parameters in the CALIPER cohort of healthy children and adolescents.

METHODS

A total of 536 healthy children and adolescents (birth to 21 years) were recruited with informed consent, and whole blood samples were analyzed for 27 hematologic parameters on the Beckman Coulter DxH 520 system. Age- and sex-specific pediatric reference standards were established. Reference values obtained on the DxH 520 were also compared with data obtained on a larger laboratory-based instrument (DxH 900).

RESULTS

Most hematologic parameters showed significant age- and/or sex-specific changes during growth and development. Of the 27 hematologic parameters, all except four (mean corpuscular hemoglobin concentration, basophil percentage, low hemoglobin density, immature cell percentage) required age partitioning, and eight required sex partitioning.

CONCLUSIONS

This study establishes a robust pediatric hematology reference database that will assist in more accurate test result interpretation. Our data clearly demonstrate significant variation in hematologic parameter concentrations in children and adolescents, necessitating the use of pediatric-specific reference standards.

Assessment of interstitial lung disease in systemic sclerosis using the quantitative CT algorithm CALIPER

Interstitial lung disease (ILD) remains a major cause of morbidity and mortality in systemic sclerosis (SSc). Study aim is to characterize and quantify SSc-ILD by using Computer-Aided Lung Informatics for Pathology Evaluation and Rating (CALIPER). Secondly, our objective is to evaluate which radiological pattern is predictive of lung function decline at 12 months follow-up. In the prospective study (IRB 5435), 66 SSc patients underwent high-resolution computerized tomography (HRCT) at baseline. HRCT was performed according to standard protocol using a CT 64GE light speed VCT power scanner. CALIPER classified lung parenchyma on volume units. Every volume unit was classified into radiological parenchymal patterns (honeycombing, reticular and ground glass). Pulmonary function tests (PFTs) were performed at baseline and after 12 months of follow-up. Cigarette smoking and other lung diseases unrelated to SSc are exclusion criteria. CALIPER analysis showed normal lung parenchyma 87.4 ± 9.8%, ground glass 2.8 ± 5.3%, reticular 4 ± 5.7%, and honeycombing 1 ± 1%. In multiple regression analysis, FEV1 (p < 0.0001), FVC (p = 0.001), and DLCO (p < 0.0001) measurements at baseline showed a negative correlation with the reticular pattern percentage. At follow-up, DLCO reduction showed a positive correlation (p < 0.001) with the percentage of ground glass pattern (r = 0.33, beta coefficient = 0.51). In the ROC curve analysis, ground glass score is a good predictor (0.75, p = 0.009; 95% CI 0.59-0.91) of DLCO worsening, defined as a decrease of more than 10% of DLCO. Using a cutoff ≥ 4.5 for ground glass score, the RR for DLCO worsening is 6.8 (p < 0.01; 95% CI 1.6-29.2). The results of this study show that CALIPER is useful not only for quantifying lung damage but also for assessing worsening PFTs, but larger studies are needed to confirm these preliminary data.Key Points• At baseline reticular pattern showed negative correlation with PFTs• At follow-up ground glass pattern predicts worsening of DLCO• CALIPER is a useful to quantify lung damage.

CALIPER paediatric reference intervals for the urea creatinine ratio in healthy children & adolescents

BACKGROUND

The urea creatinine ratio (UCR) is important in the clinical assessment of several medical conditions, including acute kidney injury and gastrointestinal bleeding. However, accurate and robust paediatric reference intervals (RIs) for this ratio have not been well established. Here, we determined age- and sex-specific discrete and continuous RIs for UCR in the Canadian Laboratory Initiative on Paediatric Reference Intervals (CALIPER) cohort of healthy children and adolescents for the first time.

METHODS

UCR was calculated for approximately 1030 CALIPER participants using retrospective urea and creatinine (both Jaffe and enzymatic methods) normative data. Partitions were determined using the Harris & Boyd statistical method. Discrete RIs were established in accordance with the Clinical and Laboratory Standards Institute (CLSI) guidelines. Continuous RIs were established using nonparametric quantile regression.

RESULTS

Several age- and sex-specific partitions were necessary to capture dynamic physiological trends associated with this ratio throughout childhood and adolescence, highlighting the benefit of continuous RI establishment. Established UCR RIs also demonstrated marked differences between Jaffe and enzymatic assay methods.

CONCLUSION

Our results clearly demonstrate the critical need for RI stratification by important covariates such as age, sex, and creatinine assay methodology for paediatric UCR test result interpretation. These data contribute to our understanding of normative UCR values in childhood and adolescence and can be expected to improve paediatric test result interpretation in clinical laboratories that report this ratio.

Pediatric reference intervals for clinical chemistry assays on Siemens ADVIA XPT/1800 and Dimension EXL in the CALIPER cohort of healthy children and adolescents

INTRODUCTION

Accurate reference intervals (RIs) are essential for clinical interpretation of laboratory test results; however, major gaps exist in pediatric RIs. The Canadian Laboratory Initiative on Pediatric Reference Intervals (CALIPER) has established age- and sex-specific pediatric RIs on various analytical platforms. The current study expands the CALIPER database by establishing age- and sex-specific RIs for biochemical assays on Siemens ADVIA XPT/1800 and Dimension EXL Systems.

METHODS

Serum samples from a total of 909 and 867 healthy children and adolescents (ages 0-<19 y) were tested on ADVIA XPT/1800 and Dimension EXL systems, respectively. Age- and/or sex-specific RIs were calculated for a total of 54 biochemical assays.

RESULTS

Serum concentrations of several biomarkers remained relatively constant across the pediatric age range and similar between sexes, including sodium and triglycerides. Other biomarkers, such as alkaline phosphatase and creatinine showed both age and sex differences. Furthermore, immunoglobulin A and iron showed only age differences.

DISCUSSION

We established RIs for creatine kinase, random glucose, total iron binding capacity, and several electrolytes for the first time using the CALIPER cohort. Overall, pediatric RIs established in the current study will allow for more accurate laboratory test interpretation worldwide using Siemens chemistry assays.

Pediatric Reference Intervals for Biochemical Markers: Gaps and Challenges, Recent National Initiatives and Future Perspectives

Reference intervals provide valuable information to medical practitioners in their interpretation of quantitative laboratory test results, and are critical in the assessment of patient health and in clinical decision-making. The reference interval serves as a health-associated benchmark with which to compare an individual test result. While the concept of reference intervals and their utility appear straightforward, the process of establishing accurate and reliable reference intervals is considerably complex and involved. Currently, many pediatric laboratory tests are inappropriately interpreted using reference intervals derived from either adult populations, hospitalized pediatric populations, or from outdated and/or inaccurate technology. Thus, many pediatric reference intervals used in diagnostic laboratories are incomplete and may be inappropriate for clinical use. The use of inappropriate reference intervals impacts clinical decision-making and has potential detrimental effects on the quality of patient healthcare including misdiagnosis, delayed diagnosis, inappropriate treatments, and patient risk. These are critical gaps in pediatric healthcare and it is imperative to update and establish appropriate reference intervals for pediatric populations based on specific age- and sex-stratifications. In the present review, specific issues, challenges and deficiencies in pediatric reference intervals for biochemical markers will be discussed. Early studies using hospitalized patients will be examined, followed by a review of recent national and global initiatives on establishing reference intervals from healthy pediatric population. We will highlight the achievements and milestones of the Canadian CALIPER project, including the establishment of a comprehensive biobank and database which has addressed several of these critical gaps. CALIPER's mandate is to establish and provide comprehensive, up-to-date pediatric reference intervals to all biochemical markers of pediatric disease. CALIPER has also begun knowledge translation initiatives to disseminate its data via peer-reviewed publication, an online database, and a smartphone application to allow greater access to CALIPER pediatric reference interval data. Finally, limitations, future perspectives and harmonization of pediatric reference intervals to improve pediatric diagnostics in Canada and worldwide will be discussed.

Pediatric Reference Intervals for Transferrin Saturation in the CALIPER Cohort of Healthy Children and Adolescents

BACKGROUND

Transferrin saturation reference intervals specific for age and sex have not been previously reported for the pediatric population. The reference values for transferrin saturation have been previously reported to be lower in children compared to adults, caused by a combination of low serum iron and high serum transferrin levels in children, warranting specific reference intervals. Here we use the original iron and transferrin data from the CALIPER cohort to establish age- and sex-specific pediatric reference intervals for transferrin saturation.

METHODS

Iron and transferrin concentrations were measured in serum samples from the CALIPER cohort of healthy children and adolescents on the Abbott Architect c8000. Transferrin saturation was subsequently calculated and statistically relevant age- and sex-partitions were determined. After removing outliers, age- and sex-specific reference intervals with corresponding 90% confidence intervals were calculated using CLSI C28-A3 guidelines.

RESULTS

Transferrin saturation required 3 separate age partitions, with an additional sex partition for 14-<19 year olds. Transferrin saturation was more variable during the first year of life, evident by a wider reference interval, which subsequently narrowed at one year until adolescence. Upon adolescence, a sex difference was apparent with females having lower percent transferrin saturation than males.

CONCLUSIONS

Age- and sex-specific pediatric reference intervals for transferrin saturation were established based on a large cohort of healthy pediatric subjects. Transference studies suggest that these intervals established using Abbott assays are comparable to those on Beckman, Ortho, Roche, and Siemens assays. Individual laboratories should however verify these reference intervals for their individual instrument and local population as per CLSI guidelines.

Advances in Pediatric Reference Intervals for Biochemical Markers: Establishment of the Caliper Database in Healthy Children and Adolescents

Clinical laboratory reference intervals provide valuable information to medical practitioners in their interpretation of quantitative laboratory test results, and therefore are critical in the assessment of patient health and in clinical decision-making. The reference interval serves as a health-associated benchmark with which to compare an individual test result. Unfortunately, critical gaps currently exist in accurate and up-to-date pediatric reference intervals for accurate interpretation of laboratory tests performed in children and adolescents. These critical gaps in the available laboratory reference intervals have the clear potential of contributing to erroneous diagnosis or misdiagnosis of many diseases. To address these important gaps, several initiatives have begun internationally by a number of bodies including the KiGGS initiative in Germany, the Aussie Normals in Australia, the AACC-National Children Study in USA, the NORICHILD Initiative in Scandinavia, and the CALIPER study in Canada. In the present article, we will review the gaps in pediatric reference intervals, challenges in establishing pediatric norms in healthy children and adolescents, and the major contributions of the CALIPER program to closing the gaps in this crucial area of pediatric laboratory medicine. We will also discuss the recently published CALIPER reference interval database (www.caliperdatabase.com) developed to provide comprehensive age and gender specific pediatric reference intervals for a larger number of biochemical markers, based on a large and diverse healthy children cohort. The CALIPER database is based on a multiethnic population examining the influence of ethnicity on laboratory reference intervals. Thus the database has proved to be of global benefit and is being adopted by hospital laboratories worldwide.

Validity of establishing pediatric reference intervals based on hospital patient data: a comparison of the modified Hoffmann approach to CALIPER reference intervals obtained in healthy children

OBJECTIVES

To compare pediatric reference intervals calculated using hospital-based patient data with those calculated using samples collected from healthy children in the community as part of the CALIPER study.

METHODS

Hospital-based data for 13 analytes (calcium, phosphate, iron, ALP, cholesterol, triglycerides, creatinine, direct bilirubin, total bilirubin, ALT, AST, albumin and magnesium), measured on the Vitros 5600, collected between 2007 and 2011 were obtained. The data for each analyte were partitioned by age and gender as previously defined by the CALIPER study. Outliers in each partition were removed using the Tukey method. The cumulative distribution function (cdf) was then determined for each analyte value following which, the inverse cdf values of a standard Gaussian distribution were calculated. The analyte values were plotted against the inverse cdf of the standard Gaussian distribution. Piece-wise regression determined the linear portion of the resulting graph using the statistical software R. Linear regression determined an equation for the linear portion in each partition and reference intervals were calculated by extrapolating to identify the 2.5th and 97.5th centiles in each partition based on the inverse cdf values (which would correspond to the values -1.96 and 1.96 of the Gaussian distribution). Using the 90% confidence intervals for the reference intervals defined by CALIPER and the Reference Change Value (RCV) as the criteria, these calculated reference intervals were compared to those reported previously by CALIPER. Reference samples were also measured on the Vitros 5600 analyzer in an attempt to validate the calculated reference intervals.

RESULTS

In general, the reference intervals calculated from hospital-based data were generally wider than those calculated by CALIPER. None of the reference intervals calculated using the Hoffmann approach fell completely within the 90% confidence intervals calculated by CALIPER.

CONCLUSIONS

These results suggest that calculating pediatric reference intervals from hospital-based data may be useful, as a guide, in some cases but will likely not replace the need to establish reference intervals in healthy pediatric populations.