Clinical Chemistry Analytes Research Articles

Establishing hemolysis and lipemia acceptance thresholds for clinical chemistry tests

BackgroundA key component of laboratory medicine is the evaluation of specimen suitability for downstream analytical testing. Accurate identification and characterization of the impact of interferents on clinical chemistry analytes is important for patient care. To empirically assess the influence of hemolysis and lipemia on clinical chemistry tests analyzed on a Roche cobas® c701 system, we evaluated serum pools spiked with increasing concentrations of hemolysate and Intralipid®. MethodsUsing an interferent acceptance threshold of within ± 10% of the non-hemolyzed or non-lipemic results, 31 routine chemistry analytes were evaluated. ResultsThe majority of analytes were determined to have the same or very similar acceptability thresholds as those listed in the vendor package insert. However, several analytes resulted in new thresholds that deviated from manufacturer recommendations (9 higher and 2 lower for lipemia, 7 higher and 6 lower for hemolysis). Samples with high enzyme activities (LDH, ALT, AST, ALP, and CK) were observed to tolerate higher levels of hemolysis, and tiered hemolysis thresholds were established for these enzymes. Independent evaluation of indices is recommended to enable thoughtful implementation of specimen quality criteria and to provide guidance to laboratorians and providers on the nature of these interferences.

Comparison of test results obtained from lithium heparin gel tubes and serum gel tubes

Abstract Objectives There is currently trend that plasma might be alternative to serum due to some of its advantages. This study aimed to compare test results from heparinized plasma and serum. Methods Blood samples from total of 40 participants (20 healthy, 20 hemodialysis patients) were drawn into serum gel tubes with clot activator and lithium heparin gel tubes. Twenty-eight clinical chemistry analytes were measured in serum and plasma samples. To determine whether difference between test results is clinically significant, total error (TE) was calculated and compared total allowable error (TEa) limits. Results TE of below 5% was calculated for amylase, AST, calcium, total cholesterol, chloride, CK, glucose, HDL-cholesterol, iron, LDH, LDL-cholesterol, magnesium, sodium, total bilirubin, uric acid and urea. Albumin, ALT, creatinine, CRP, lipase, phosphorus, potassium, total protein, and triglyceride had TE of 5–7%. TE of 7–10% were determined for ALP, direct bilirubin, and GGT. TE values were within TEa limits for all analytes. Conclusions It was concluded that results of 28 analytes measured in lithium heparin gel tubes are comparable to those of serum gel tubes. It is thought that several advantages including reduced turnaround time might be provided by using plasma instead of serum for these tests.

Metabolome and proteome changes in skeletal muscle and blood of pre-weaning calves fed leucine and threonine supplemented diets

In pre-weaning calves, both leucine and threonine play important roles in growth and muscle metabolism. In this study, metabolomics, proteomics and clinical chemistry were used to assess the effects of leucine and threonine supplementation added to milk replacer on 14 newborn Holstein male calves: 7 were fed a control diet (Ctrl) and 7 were fed the Ctrl diet supplemented with 0.3% leucine and 0.3% threonine (LT) from 5.6 days of age to 53.6 days. At this time, blood and semitendinosus muscle biopsies were collected for analysis. Integrated metabolomics and proteomics showed that branched-chain amino acids (BCAA) degradation and mitochondrial oxidative metabolism (citrate cycle and respiratory chain) were the main activated pathways in muscle because of the supplementation. BCAA derivatives and metabolites related to lipid mobilization showed the major changes. The deleterious effects of activated oxidative phosphorylation were balanced by the upregulation of antioxidant proteins. An increase in protein synthesis was indicated by elevated aminoacyl-tRNA biosynthesis and increased S6 ribosomal protein phosphorylation in skeletal muscle. In conclusion, LT group showed greater BCAA availability and mitochondrial oxidative activity; as the muscle cells undergo greater aerobic metabolism, antioxidant defenses were activated to compensate for possible cell damage. Data are available via ProteomeXchange (PXD016098). SignificanceLeucine and threonine are essential amino acids for the pre-weaning calf, being of high importance for growth. In this study, we found that leucine and threonine supplementation of milk replacer to feed pre-weaning calves led to differences in the proteome, metabolome and clinical chemistry analytes in skeletal muscle and plasma, albeit no differences in productive performance were recorded. This study extends our understanding on the metabolism in dairy calves and helps optimizing their nutritional status.

Interference From High-Dose Biotin Intake in Immunoassays for Potentially Time-Critical Analytes by Roche.

Immunoassays using the interaction between streptavidin and biotin are used for clinical chemical analytes on platforms by many different manufacturers. The design can be susceptible to interference from high-dose biotin intake in patients, which remains an often-overlooked confounder despite recently increased awareness. To evaluate an easily implementable method of in vitro biotin depletion for the removal of biotin interference in immunoassays for potentially time-critical analytes. A biotin stock solution was made and de-identified patient samples were spiked to reach a biotin concentration of 1.126 × 106 pg/mL, the maximum reported biotin concentration 1 to 2 hours after a single oral dose of 300 mg biotin. Then, the resulting interference in Elecsys immunoassays for cortisol, cyclosporine A, tacrolimus, digitoxin, thyroid-stimulating hormone, free triiodothyronine, free thyroxine, C-peptide, insulin, N-terminal pro-B-type natriuretic peptide, troponin T high sensitive, human immunodeficiency virus, procalcitonin, β human chorionic gonadotropin, toxoplasma immunoglobulin M, and toxoplasma immunoglobulin G was evaluated before and after biotin depletion using streptavidin particles. All tested immunoassays, with the exception of toxoplasma immunoglobulin M and toxoplasma immunoglobulin G, suffered from significant biotin interference. The depletion protocol removed assay interference due to biotin and produced results that were close or identical to initial prespike measurements. Despite an increase in turnaround times, biotin adsorption is a feasible countermeasure for biotin interference in Elecsys immunoassays. Until test kits with an increased resistance to the interference from high-dose biotin intake are distributed, the evaluated protocol can provide results properly reflecting the patient's clinical condition.

Comparison of Application Biological Variation and Patient Data for Selecting Delta Check Limits.

This study aimed to evaluate delta check limits set by reference change value (RCV) and patient data. Patient data of 11 clinical chemistry analytes from June 2018 to May 2019 were collected. RCV with 95% or 99% levels of probability were calculated based on biological variation. The corresponding delta check limits for outpatients and inpatients were calculated by 95% or 99% central range of delta% which was the difference of two consecutive results within thirty days of the same patient for each analyte. Patient data in June 2019 were used to analyze the utility of delta check limits. In total, 434,927 paired results for these 11 analytes were included. The delta check limits were different between outpatients and inpatients, but were wider than those established by RCV. The difference between Glu's outpatient and inpatient boundaries was the largest, 95% central range from the outpatient (inpatients) was from -32.29% (-56.97%) to 38.78% (106.00%) while 99% central range from the outpatient (inpatients) was from -56.86% (-90.56%) to 89.96% (262.54%). The RCV is mainly determined by within-individual biological variation so that the RCV of each analyte varied from each other. As for RCV, Na had the lowest value and BUN had the highest one. In addition, the main reason for delta% exceeding delta check limits was a clinically significant change. Laboratories could use delta check procedure to find out errors in sample collection and monitor clinical significance. When delta% of patients exceed corresponding delta check limits in a short time, clinicians and personnel of clinical laboratory should pay more attention. Delta check limits should be reviewed regularly to check the utility of procedure.

CHALLENGES TO ANIMAL WELFARE ASSOCIATED WITH CAPTURE AND LONG ROAD TRANSPORT IN BOMA-ADAPTED BLACK (DICEROS BICORNIS) AND SEMI-CAPTIVE WHITE (CERATOTHERIUM SIMUM) RHINOCEROSES

Capture and transport are part of translocation and expose animals to a variety of stressors that can lead to morbidity and mortality. We aimed to establish a better understanding of the physiologic responses to capture and transport in black (Diceros bicornis) and white (Ceratotherium simum) rhinoceroses in Southern Africa. Fourteen adult black rhinoceroses were transported 600 km by vehicle and 32 white rhinoceroses (24 adults and 8 juveniles) were transported 1,300 km by vehicle. The black rhinoceroses had been wild-caught and boma-adapted over 6 wk prior to the translocation and were only sedated to allow for loading into the transport crates. The white rhinoceroses originated from a game farm and were chemically immobilized from a helicopter and then loaded. Paired blood samples were collected from animals at loading (capture) and after transport and evaluated for changes in clinical chemistry analytes, acute phase reactants, and oxidative stress biomarkers. The Wilcoxon rank sum test was used to compare changes in measured analytes from capture and after transport. All rhinoceroses survived capture and transport. Rhinoceroses experienced total body water loss, mobilization of energy reserves, and muscular damage. Alterations in acute phase reactants suggested that animals mounted a stress response. Oxidative stress was observed in black rhinoceroses. We identified the following challenges to animal welfare during transport: hydration status, energy balance, skeletal muscle fatigue, and stress-induced immunomodulation. Measures to mitigate these challenges, such as administration of fluids, need to be included in the planning of future translocations.

Handling of hemolyzed serum samples in clinical chemistry laboratories: the Nordic hemolysis project.

Background Some clinical chemistry measurement methods are vulnerable to interference if hemolyzed serum samples are used. The aims of this study were: (1) to obtain updated information about how hemolysis affects clinical chemistry test results on different instrument platforms used in Nordic laboratories, and (2) to obtain data on how test results from hemolyzed samples are reported in Nordic laboratories. Methods Four identical samples containing different degrees of hemolysis were prepared and distributed to 145 laboratories in the Nordic countries. The laboratories were asked to measure the concentration of cell-free hemoglobin (Hb), together with 15 clinical chemistry analytes. In addition, the laboratories completed a questionnaire about how hemolyzed samples are handled and reported. Results Automated detection of hemolysis in all routine patient samples was used by 63% of laboratories, and 88% had written procedures on how to handle hemolyzed samples. The different instrument platforms measured comparable mean Hb concentrations in the four samples. For most analytes, hemolysis caused a homogenous degree of interference regardless of the instrument platform used, except for alkaline phosphatase (ALP), bilirubin (total) and creatine kinase (CK). The recommended cut-off points for rejection of a result varied substantially between the manufacturers. The laboratories differed in how they reported test results, even when they used the same type of instrument. Conclusions Most of the analytes were homogeneously affected by hemolysis, regardless of the instrument used. There is large variation, however, between the laboratories on how they report test results from hemolyzed samples, even when they use the same type of instrument.

Evaluation of the long-term stability of clinical chemistry analytes for human biobanking specimen

Evaluation of the long-term stability of clinical chemistry analytes for human biobanking specimen

Uncertainty evaluation in clinical chemistry, immunoassay, hematology and coagulation analytes using only external quality assessment data.

Measurement uncertainty (MU) is a parameter associated with the result of a measurement that characterizes its dispersion. We report results for estimating MU following the application of a top-down procedure using only proficiency test data to establish uncertainty levels for various analytes. Data were obtained from 142 laboratories participating in the Beijing Center for Clinical Laboratory (BCCL) proficiency testing/external quality assessment (PT/EQA) schemes. The 24-month study included six selected PT shipments to obtain estimates for 50th percentile (median) and 90th percentile MUs and to compare those estimates to usual analytic goals. The number of laboratory participants varied for each trial. The expanded uncertainty (U) was calculated using a cover factor of k=2 for a confidence interval of 95%. All reproducibility, method and laboratory biases came from the PT/EQA data. The median U (k=2) ranged from 3.2% (plasma sodium, indirect ion selective electrode) to 32.8% (triglycerides, free glycerol blanking) for clinical chemistry analyte means from participants in the same method group. Immunoassay analyte median U results ranged from 11.3% (CA125 tumor marker, Roche) to 33.8% (prostate-specific antigen [PSA], Abbott). The range for median U was 3.5% (red blood cell [RBC], Abx) to 30.3% (fibrinogen [FBG], other) for hematology and coagulation analytes. The MUs for most analytes satisfied quality requirements. The use of PT/EQA data, when available, provides an effective means for estimating uncertainties associated with quantitative measurements. Thus, medical laboratories can calculate their own MUs. Proficiency testing organizers can provide participants with an additional MU estimate using only EQA data, which may be updated at the end of each survey.

Validation conform ISO-15189 of assays in the field of autoimmunity: Joint efforts in The Netherlands.

ISO 15189:2012 requires validation of methods used in the medical laboratory, and lists a series of performance parameters for consideration to include. Although these performance parameters are feasible for clinical chemistry analytes, application in the validation of autoimmunity tests is a challenge. Lack of gold standards or reference methods in combination with the scarcity of well-defined diagnostic samples of patients with rare diseases make validation of new assays difficult. The present manuscript describes the initiative of Dutch medical immunology laboratory specialists to combine efforts and perform multi-center validation studies of new assays in the field of autoimmunity. Validation data and reports are made available to interested Dutch laboratory specialists.

Evaluation of the effects of calibration modes and sample reconstitution on the analytic precision of 26 clinical chemistry analytes using system measurement procedure

Objective To evaluate the system measurement procedure effects on the analytic precision of clinical chemistry analytes. Methods In June 2009, June 2010 and September 2010 respectively, the National Center for Clinical Laboratories of China and the Organization of Five Hospitals in Fukuoka Japan organized comparison activities of 26 clinical chemistry analytes which were ALT, AST, GGT, ALP, CK, LDH, AMY, ChE, TG, TC, HDL-C, LDL-C, Glu, Cr, BUN, UA, K, Na, Cl, Ca, TP, Alb, TBil, DBil, P, Fe.In this paper, we investigated 26 analytes of three sets in Beijing Aerospace General Hospital as follows. (1) The precision of different reconstitution methods was observed by using three kinds of pipetting tools, such as measuring pipette, pipette and dispenser. (2) The experiments were carried out in three stages by testing the dried powder control samples of two concentration levels (101-Ⅰ, 101-Ⅱ) provided by Hitachi Japan. They were measured on 28 consecutive days at each stage in order to observe the precision of 26 clinical chemistry analytes. In the first stage, we used the former measurement procedure to measure the control samples; in the second stage we added three conditions of the measurement procedure. The first was two calibration modes, which were once-a--day calibration and twice-a--day calibration. The second was the calibration standard and the last was the conditions of the freeze-thaw samples. In the third stage, we used the twice-a-day calibration only for GGT, ALP, ChE, TG, Cr, Na, K, CL, ALB. (3) JSCC and Health Industry Standard quality objectives were implemented to evaluate whether the precision of the improved measurement procedure met the requirements.(4) Paired T test were used to compare the precision of measurement between the second stage and the first stage, and between the third stage and the second stage of the measurement procedure. Results (1)The precision of three kinds of pipetting tools were 0.56%, 0.10%, 0.01%.(2)The ranges of precision of ALT, AST, GGT, ALP, CK, LDH, AMY, ChE, TG, TC, HDL-C, LDL-C, Glu, Cr, BUN, UA, K, Na, Cl, Ca, TP, Alb, TBil, DBil, P, Fe were 0.99%-10.5% about 101-Ⅰ and 0.91%-7.03% about 101-Ⅱ in the first stage. The ranges of precision were 0.66%-8.81% of 101-Ⅰ and 0.66%-4.28% of 101-Ⅱ in the second stage. The ranges of precisions were 0.60%-3.91% of 101-Ⅰ and 0.73%-3.39% of 101-Ⅱ in the third stage.(3)73%/80% of the samples met the standard of JSCC about 101-Ⅰ and 101-Ⅱ and 80%/88% of the samples met the standard of Health Industry Standard in the first stage. 88%/100% of the samples met the standard of JSCC about 101-Ⅰand 101-Ⅱ and 100%/100% samples met the standard of Health Industry Standard in the second stage. The ratio of samples meeting the standard of JSCC about 101-Ⅰand 101-Ⅱwere 96%/100% and that of Health Industry Standard were 100%/100% in the third stage.(4)Precision of 101-Ⅰ and 101-Ⅱ was statistically significant between the measurement procedures of second stage and the first stage, and there was no significant difference between the third stage and the second stage. Conclusion (1) The precision of samples using dispenser to reconstitute is higher than that of the other two pipetting methods. (2) Improving the calibration mode and reconstitution of samples increase the precision of 26 clinical chemistry analytes by over 50%. (Chin J Lab Med, 2018, 41: 149-154) Key words: Chemistry, clinical; Calibration; Reference values; Laboratories, hospital; Diagnostic tests, routine

Estabilidad de analitos conservados en tubo cerrado con film versus cerrado con tapa plástica

IntroductionThe laboratory must be able to guarantee the stability of stored patient samples for confirmation of results or errors in the interpretation of the medical request. The aim of this study was to evaluate the stability of the blood analytes preserved in tubes sealed with film versus a plastic cap. Material and methodsA total of 24 blood samples were aliquoted into two tubes; one sealed with film, and the other with a plastic cap. Twenty-six clinical chemistry analytes were measured for 7 consecutive days using a Roche Cobas c 501 autoanalyser. The samples were stored in a refrigerator between 2-8C. The total error and coefficient of variation were calculated, and the results were compared against the quality requirements of the laboratory. ConclusionsThe variation was higher in the tubes sealed with film than in those with a plastic cap. Enzymes remained within the quality requirements for four days, and ions, apart from iron, were stable for only one day. The metabolites were stable for seven days excluding glucose, uric acid, total proteins, and albumin. It is suggested that each laboratory must evaluate the stability of analytes based on its workflow.

An update report on the harmonization of adult reference intervals in Australasia.

The Australasian Association of Clinical Biochemists (AACB) has over the past 5 years been actively working to achieve harmonized reference intervals (RIs) for common clinical chemistry analytes using an evidence-based checklist approach where there is sound calibration and metrological traceability. It has now recommended harmonized RIs for 18 common clinical chemistry analytes which are performed in most routine laboratories and these have been endorsed by the Royal College of Pathologists of Australasia (RCPA). In 2017 another group of analytes including urea, albumin and arterial blood gas parameters were considered and suggested harmonized RIs proposed. This report provides an update of those harmonization efforts.

Fasting conditions: Influence of water intake on clinical chemistry analytes.

IntroductionCurrently available recommendations regarding fasting requirements before phlebotomy do not specify any maximum water intake volume permitted during the fasting period. The aim was to study the effects of 300 mL water intake 1 h before phlebotomy on specific analytes.Materials and methodsBlood was collected from 20 women (median age (min-max): 24 (22 - 50) years) in basal state (T0) and 1 h after 300 mL water intake (T1). Glucose, total proteins (TP), urea, creatinine, cystatin C, total bilirubin (BT), total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides (Tg), uric acid (UA), high-sensitivity C-reactive protein, gamma-glutamyl transferase (GGT), aspartate-aminotransferase (AST), alanine-aminotransferase and lactate-dehydrogenase (LD) were studied. Results were analyzed using Wilcoxon test. Mean difference (%) was calculated for each analyte and was further compared with reference change value (RCV). Only mean differences (%) higher than RCV were considered clinically significant.ResultsSignificant differences (median T0 vs median T1, P) were observed for TP (73 vs 74 g/L, 0.001); urea (4.08 vs 4.16 mmol/L, 0.010); BT (12 vs 13 µmol/L, 0.021); total cholesterol (4.9 vs 4.9 mmol/L, 0.042); Tg (1.05 vs 1.06 mmol/L, 0.002); UA (260 vs 270 µmol/L, 0.006); GGT (12 vs 12 U/L, 0.046); AST (22 vs 24 U/L, 0.001); and LD (364 vs 386 U/L, 0.001). Although the differences observed were statistically significant, they were not indicative of clinically significant changes.ConclusionsA water intake of 300 mL 1 h prior to phlebotomy does not interfere with the analytes studied in the present work.

Quality specifications of routine clinical chemistry methods based on sigma metrics in performance evaluation.

Sigma metrics were applied to evaluate the performance of 20 routine chemistry assays, and individual quality control criteria were established based on the sigma values of different assays. Precisions were expressed as the average coefficient variations (CVs) of long-term two-level chemistry controls. The biases of the 20 assays were obtained from the results of trueness programs organized by National Center for Clinical Laboratories (NCCL, China) in 2016. Four different allowable total error (TEa) targets were chosen from biological variation (minimum, desirable, optimal), Clinical Laboratory Improvements Amendments (CLIA, US), Analytical Quality Specification for Routine Analytes in Clinical Chemistry (WS/T 403-2012, China) and the National Cholesterol Education Program (NECP). The sigma values from different TEa targets varied. The TEa targets for ALT, AMY, Ca, CHOL, CK, Crea, GGT, K, LDH, Mg, Na, TG, TP, UA and Urea were chosen from WS/T 403-2012; the targets for ALP, AST and GLU were chosen from CLIA; the target for K was chosen from desirable biological variation; and the targets for HDL and LDL were chosen from the NECP. Individual quality criteria were established based on different sigma values. Sigma metrics are an optimal tool to evaluate the performance of different assays. An assay with a high value could use a simple internal quality control rule, while an assay with a low value should be monitored strictly.

The study of statistical methods for evaluating the comparability of routine chemistry analytes among 3 routine laboratory measurement systems in China.

BackgroundClinical laboratory tests are important for clinicians to make diagnostic decisions, but discrepancies may directly lead to incorrect diagnosis. We would like to introduce some statistical methods to evaluate the comparability of chemistry analytes while comparing the performances of different measurement systems.MethodsWe used a panel of 10 fresh-frozen single donation serum samples to assess assays for the measurement of glucose and other 13 analytes. Statistical methods used in this article include traditional statistical analysis, robust statistics, regression analysis and differences on medical decision levels (MDL). All the statistical analysis results would be evaluated. 20 Chinese tertiary hospitals accredited to ISO 15189 took part in this work. The commercial random access platforms included: Olympus (8 labs), Hitachi (6 labs) and Roche (6 labs). To compare the acceptable rates, Chi square test was used.ResultsThe statistical analysis results are as follows: (1) Coefficient of variations are between 2.8 and 3.9 %, with the slopes and intercepts of regression functions between 0.928 to 1.064 and −0.174 to 0.630, respectively. (2) The percentage of robust z-scores between −2 and 2 is bigger than 90 %. (3) The total percentages of differences on all the MDLs are: less than optimal was 31.7 % (19/60); less than desirable was 60.0 % (36/60); less than minimum was 65.0 % (39/60); more than minimum was 35.0 % (21/60). In this study, 2 laboratories (Nos. 8 and 16) were considered as poor performance by z-scores. 10 laboratories (Nos. 4, 5, 7, 8, 9, 10, 11, 14, 16 and 19) have unacceptable measurement errors on MDLs. 10 laboratories (Nos. 1, 2, 3, 6, 12, 13, 15, 17, 18, 20) can achieve mutual recognition of serum glucose testing results, including: 5 (5/8) Olympus, 2 (2/6) Hitachi and 3 (3/6) Roche. There was no significant difference among acceptable rates of the three measurements systems for the serum glucose assay.ConclusionsTraditional statistical analysis, robust statistics and robust z-score, fitting linear regression equations and calculating differences on different MDLs can be used on studying the comparability and mutual recognition of clinical chemistry analytes among hospitals or laboratories in China. The mutual recognition and interchangeability of results remains jeopardized even among tertiary hospitals in China. More works and efforts should be done for improvement of the current situation of interchangeability of results in clinical laboratories in China.

Ninety-day toxicity and single-dose toxicokinetics study of alpha-glycosyl isoquercitrin in Sprague-Dawley rats

alpha-Glycosyl isoquercitrin (AGIQ) is highly absorbable and has been shown to possess antioxidative properties. Based on a favorable safety profile, it has been confirmed as generally recognized as safe (GRAS) compound by the FDA. Nevertheless, safety and toxicity information for AGIQ is still sparse. Therefore, the aim of this study was to test the safety and toxicokinetics of AGIQ in a 90-day study in 60 male and 60 female Sprague-Dawley rats at dietary doses up to 5%. All animals survived until scheduled euthanasia with no clinical signs of toxicity in any animal. AGIQ was rapidly absorbed with metabolism to quercetin and quercetin glucuronide at all dose levels. Statistically significant changes were noted in some tissue weights and clinical chemistry analytes, without evidence of systemic toxicity. The most prominent finding was systemic dose dependent yellow discoloration of bones of treated animals. However, no changes were observed microscopically, and this observation was concluded as toxicologically insignificant. The overall lack of adverse clinical signs, changes in body weight, feed consumption, clinical pathology parameters, and histopathological endpoints in animals administered AGIQ supports no observable adverse effect levels (NOAEL) of 5.0% in diet for both male and female rats (3461 mg/kg/day and 3867 mg/kg/day, respectively).

A global multicenter study on reference values: 2. Exploration of sources of variation across the countries

ObjectivesThe intent of this study, based on a global multicenter study of reference values (RVs) for serum analytes was to explore biological sources of variation (SVs) of the RVs among 12 countries around the world. MethodsAs described in the first part of this paper, RVs of 50 major serum analytes from 13,396 healthy individuals living in 12 countries were obtained. Analyzed in this study were 23 clinical chemistry analytes and 8 analytes measured by immunoturbidimetry. Multiple regression analysis was performed for each gender, country by country, analyte by analyte, by setting four major SVs (age, BMI, and levels of drinking and smoking) as a fixed set of explanatory variables. For analytes with skewed distributions, log-transformation was applied. The association of each source of variation with RVs was expressed as the partial correlation coefficient (rp). ResultsObvious gender and age-related changes in the RVs were observed in many analytes, almost consistently between countries. Compilation of age-related variations of RVs after adjusting for between-country differences revealed peculiar patterns specific to each analyte. Judged fromthe rp, BMI related changes were observed for many nutritional and inflammatory markers in almost all countries. However, the slope of linear regression of BMI vs. RV differed greatly among countries for some analytes. Alcohol and smoking-related changes were observed less conspicuously in a limited number of analytes. ConclusionThe features of sex, age, alcohol, and smoking-related changes in RVs of the analytes were largely comparable worldwide. The finding of differences in BMI-related changes among countries in some analytes is quite relevant to understanding ethnic differences in susceptibility to nutritionally related diseases.

Accreditation in autoimmune diagnostic laboratories. A position paper of the European Autoimmunity Standardisation Initiative (EASI).

Reliable autoantibody detection is important for early diagnosis and appropriate treatment of autoimmune disorders. However, in contrast to testing for classical clinical chemistry analytes, autoantibody testing is complex and evolving. Moreover, there is a lack of standardization. Nevertheless, it is important that laboratories that provide autoimmune tests comply with the requirements set forward by general international accreditation bodies. In the present manuscript, an ad hoc committee of the European Autoimmunity Standardisation Initiative (EASI) group provides background information on accreditation and identifies the minimum requirements needed to set up an accredited autoimmunity lab and to ensure that high-quality results are provided (in terms of personnel, procedures, validation, quality control, and reporting). Areas in which additional work needs to be done are identified.

Selected clinical chemistry analytes correlate with the pathogenesis of inclusion body hepatitis experimentally induced by fowl aviadenoviruses

ABSTRACTIn the present study, clinical chemistry was applied to assess the pathogenesis and progression of experimentally induced inclusion body hepatitis (IBH). For this, five fowl aviadenovirus (FAdV) strains from recent IBH field outbreaks were used to orally inoculate different groups of day-old specific pathogen-free chickens, which were weighed, sampled and examined during necropsy by sequential killing. Mortalities of 50% and 30% were recorded in two groups between 6 and 9 days post-infection (dpi), along with a decreased weight of 23% and 20%, respectively, compared to the control group. Macroscopical changes were seen in the liver and kidney between 6 and 10 dpi, with no lesions being observed in the other organs. Histological lesions were observed in the liver and pancreas during the same period. Plasma was collected from killed birds of each group at each time point and the following clinical chemistry analytes were investigated: aspartate aminotransferase (AST), glutamate dehydrogenase (GLDH), bile acids, total protein, albumin, uric acid and lipase. Plasma protein profile, AST and GLDH, together with bile acids values paralleled the macroscopical and histopathological lesions in the liver, while plasma lipase activity levels coincided with lesions observed in pancreas. In agreement with the histology and clinical chemistry, viral load in the target organs, liver and pancreas, was highest at 7 dpi. Thus, clinical chemistry was found to be a valuable tool in evaluating and monitoring the progression of IBH in experimentally infected birds, providing a deeper knowledge of the underlying pathophysiological mechanisms of a FAdV infection in chickens.