Comparison of three different protocols for obtaining hemolysis.

OBJECTIVES: Hemolysis is associated with erroneous or delayed results. Objectives of the study were to compare four different methods for obtaining hemolysis in vitro on three different analyzers. METHODS: Hemolysis was prepared with addition of pure hemoglobin into serum pool, osmotic shock, aspiration through blood collection needle, freezing/thawing of whole blood. Biochemistry parameters were measured in duplicate at Architect c8000 (Abbott, Abbott Park, USA), Beckman Coulter AU680 (Beckman Coulter, Brea, USA) and Cobas 6000 c501 (Roche, Mannheim, Germany), according to manufacturers' declarations. Cut-off value was defined as the highest value of H index with corresponding bias lower than acceptance criteria. RESULTS: We were not able to obtain results with freezing protocol. On all three platforms, lowest number of analytes were sensitive to hemolysis at H=0.5 using method of adding free hemoglobin. When osmotic shock was used, cut-off values for the most analytes were generally met at lower values. Hemolysis significantly interfered with measurement of potassium and lactate dehydrogenase (LD) at H=0.5 on all platforms. The most of the tested analytes had the lowest acceptable H index when aspiration method was used. At the low level of hemolysis (H=0.8) glucose, sodium, potassium, chloride, phosphate, and LD were affected on all analyzers, with some additional analytes depending on the manufacturer. CONCLUSIONS: Hemolysis interference differs on different analyzers and according to protocol for obtaining hemolysis. Aspiration method was generally the most sensitive to hemolysis interference, while addition of free Hb was the most resistant.

Association of polymorphisms in promoter region of TNF-α -238 and -308 with clinical outcomes in patients with immune-mediated inflammatory diseases on anti-TNF therapy.

The hypothesis of the study was that polymorphisms in promoter regions -238 and -308 of TNF-α could be associated with different clinical outcomes in inflammatory bowel diseases (IBD) and immune-mediated rheumatic diseases (IMRD). The aim was to examine the possible association of both polymorphisms with concentration of C-reactive protein (CRP) and fecal calprotectin (fCAL), onset of the remission and development of the ADA in patients on therapy with anti-TNF inhibitors. The prospective study was done in patients with IBD and IMRD on infliximab (IFX) or adalimumab (ADM). Patients were genotyped for TNF-α -238 and -308 polymorphisms. The concentration of CRP, fCAL, IFX or ADM and antibodies to drugs were measured according to manufacturer's instructions and followed-up for 6 or 12 months. Out of all patients (N = 112), number of patients in remission did not differ according to genotypes (for IBD patients P = 0.509 vs 0.223; for IMRD patients P = 0.541 vs 0.132 for TNF-α -238 and -308, respectively). Initial CRP concentration was higher in IBD patients with TNF-α -308 GG than GA/AA genotypes in patients who failed to achieve remission [11.8 (4.4-39.6) vs 3.1 (1.5-6.5), P = 0.033]. In IBD patients with remission, fCAL concentration after at least 6 months of therapy was higher in TNF-α-308 GG than in GA genotype [52 (25-552) vs 20 (20-20) µg/g, P = 0.041]. Our results showed the association of TNF-α -308 GG genotype with a higher concentration of CRP and fecal calprotectin in patients with inflammatory bowel diseases on IFX or ADM therapy. Clinical remission and development of antibodies to anti-TNF drugs were not associated with TNF-α -238 and -308 polymorphisms.

Lower concentration of vitamin D is associated with lower DAS28 and VAS-pain scores in patients with inflammatory rheumatic diseases treated with infliximab: a pilot study.

Vitamin D is beneficial in patients with immune-mediated rheumatic diseases as it has been shown that it lowers the incidence risk and the level of inflammation. To examine the association between clinical outcomes and initial 25-hydroxyvitamin D [25(OH)D] concentrations in patients with the immune-mediated rheumatic diseases treated with infliximab for 9 months. This study was performed in patients with rheumatoid arthritis (RA), ankylosing spondylitis (AS) and psoriatic arthritis (PsA) treated with infliximab for at least 38 weeks. Disease activity was assessed using Disease Activity Score (DAS28) for RA and PsA and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) for AS, while the global assessment was performed using the Visual Analogue Scale (VAS). Patients were divided into 2 groups according to 25(OH)D concentration which was classified as deficient or non-deficient (below and above 50 nmol/L, respectively). Concentrations of infliximab (IFX) and C-reactive protein (CRP) were measured according to the manufacturer's instructions.This study was performed in patients with rheumatoid arthritis (RA), ankylosing spondylitis (AS) and psoriatic arthritis (PsA) treated with infliximab for at least 38 weeks. Disease activity was assessed using Disease Activity Score (DAS28) for RA and PsA and Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) for AS, while the global assessment was performed using the Visual Analogue Scale (VAS). Patients were divided into 2 groups according to 25(OH)D concentration which was classified as deficient or non-deficient (below and above 50 nmol/L, respectively). Concentrations of infliximab (IFX) and C-reactive protein (CRP) were measured according to the manufacturer's instructions. The study included 23 patients (14 with RA, 6 with AS and 3 with PsA), median age 54 years, 15 females. Vitamin D deficient and non-deficient groups had median initial concentrations of 38 and 61 nmol/L, respectively. DAS28 and pain on VAS calculated at the 2nd and 38th week showed a statistically significant decrease only in RA and PsA patients with vitamin D deficiency (P = 0.02 and 0.06, respectively). Lower initial concentration of 25(OH)D in patients treated with infliximab was associated with better improvement of clinical measures (DAS28 and VAS) of disease after 9 months of therapy.

Integrity of serum samples is changed by modified centrifugation conditions.

Background Serum samples should be centrifuged for at least 10 min at 1300-2500 × g. Changed centrifugation conditions could compromise sample quality. The objective of this study was to compare the serum quality and turnaround time (TAT) using different centrifugation conditions. Methods The study was done in four different periods (A, B, C and D) at different conditions: for 10, 5 and 7 (A, B and C, respectively) at 2876 × g, and 7 (D) min at 4141 × g. Sample quality was assessed as the proportion of samples with: (a) aspiration errors, (b) H index >0.5 g/L and (c) suppressed reports of potassium (K) due to hemolysis. TAT was calculated for emergency samples. The proportions of samples (a), (b) and (c) were compared according to period A. Results The number of aspiration errors was significantly higher in samples centrifuged at 2876 × g for 5 min (p = 0.021) and remained unchanged when centrifuged for 7 min (p = 0.066 and 0.177, for periods C and D, respectively). In periods B, C and D, the proportion of samples with hemolysis was higher than that in period A (p-values 0.039, 0.009 and 0.042, respectively). TAT differed between all periods (p < 0.001), with the lowest TAT observed for B and D. The lowest number of samples exceeding 60-min TAT was observed in period D (p = 0.011). Conclusions The integrity of serum samples is changed with different centrifugation conditions than those recommended. Our study showed that shorter centrifugation at higher force (7 min at 4141 × g) significantly decreases TAT, with unchanged proportion of samples with aspiration errors.

Visual assessment of hemolysis affects patient safety.

BACKGROUND: Manual handling of hemolyzed samples is not standardized and is vulnerable to errors. This study aimed to evaluate laboratory errors due to manual handling of hemolyzed samples and to assess the risk they might have for patient safety. METHODS: Data were retrospectively obtained from a laboratory information system for 25 emergency tests from hemolyzed samples. Hemolysis (concentration of free hemoglobin >0.5 g/L) was visually assessed by comparison with a color chart. The reference person reestimated the routinely assessed degree of hemolysis to all samples (n=3185) received in the laboratory in a 1-week period. For each test, the correct and incorrect way of handling results was determined. Risk assessment was performed according to ISO 14971 standard with five categories of risk (S1-S5) and error occurrence (O1-O5). RESULTS: In the studied period, the emergency laboratory received 495 hemolyzed samples (15.5%) with a total of 2518 laboratory test requests (15.5%): 102 (20.6%) of the reports from hemolyzed samples had a comment on hemolysis; 31% of the test results were handled incorrectly (20.7% due to the incorrect release of the test result despite hemolysis interference and 10.3% due to unnecessary suppression), accounting for 4.8% of the total test volume. Tests with the highest combination of risk and occurrence rate were troponin T, potassium and total bilirubin. CONCLUSIONS: Manual handling of hemolyzed samples may lead to risk of errors in reporting results for troponin T, potassium and total bilirubin, which may have an effect on clinical decision. In addition, unnecessary suppression of the sample results unaffected by hemolysis could affect patient outcome.

Precision, accuracy, cross reactivity and comparability of serum indices measurement on Abbott Architect c8000, Beckman Coulter AU5800 and Roche Cobas 6000 c501 clinical chemistry analyzers.

BACKGROUND: The aim of our study was to perform verification of serum indices on three clinical chemistry platforms. METHODS: This study was done on three analyzers: Abbott Architect c8000, Beckman Coulter AU5800 (BC) and Roche Cobas 6000 c501. The following analytical specifications were verified: precision (two patient samples), accuracy (sample with the highest concentration of interferent was serially diluted and measured values compared to theoretical values), comparability (120 patients samples) and cross reactivity (samples with increasing concentrations of interferent were divided in two aliquots and remaining interferents were added in each aliquot. Measurements were done before and after adding interferents). RESULTS: Best results for precision were obtained for the H index (0.72%-2.08%). Accuracy for the H index was acceptable for Cobas and BC, while on Architect, deviations in the high concentration range were observed (y=0.02 [0.01-0.07]+1.07 [1.06-1.08]x). All three analyzers showed acceptable results in evaluating accuracy of L index and unacceptable results for I index. The H index was comparable between BC and both, Architect (Cohen's κ [95% CI]=0.795 [0.692-0.898]) and Roche (Cohen's κ [95% CI]=0.825 [0.729-0.922]), while Roche and Architect were not comparable. The I index was not comparable between all analyzer combinations, while the L index was only comparable between Abbott and BC. Cross reactivity analysis mostly showed that serum indices measurement is affected when a combination of interferences is present. CONCLUSIONS: There is heterogeneity between analyzers in the hemolysis, icteria, lipemia (HIL) quality performance. Verification of serum indices in routine work is necessary to establish analytical specifications.

Patient's knowledge and awareness about the effect of the over-the-counter (OTC) drugs and dietary supplements on laboratory test results: a survey in 18 European countries.

Background Nowadays over-the-counter (OTC) drugs and dietary supplements are widely used. Their use can have a significant impact on the validity of laboratory results. The aim of this multicenter European study was to determine the frequency of consumption of various dietary products and OTC drugs among patients and explore their level of knowledge and awareness about the potential impact of various products on laboratory test results. Methods Eighteen European countries participated in this study. The survey was carried out anonymously on a subsequent series of outpatients (n=200) in each participating country. Included were patients who were referred to the laboratory for blood sampling and who voluntarily agreed to participate in the study. The survey included questions about the frequency of consumption of various products, awareness of the importance of informing physicians and laboratory staff about it and information about influence of preanalytical factors in general on laboratory test results. Results In total, 68% of patients were regularly taking at least one OTC drug or dietary supplement. The frequency of patients consuming at least one OTC drug or dietary supplement differed between countries (p=0.001). Vitamins (38%), minerals (34%), cranberry juice (20%), acetylsalicylic acid (ASA) (17%) and omega fatty acids (17%) were the most commonly used in our study. Conclusions The use of various OTC drugs and dietary supplements is highly prevalent in Europe and patients are often not willing to disclose this information to the laboratory staff and ordering physician. The education of both patients and healthcare staff is needed.

Ascorbic acid-A black hole of urine chemistry screening.

BACKGROUND: Study was performed in order: (i) to assess the comparability of glucose, bilirubin, hemoglobin, leukocyte esterase, and protein; (ii) to assess accuracy of glucose, bilirubin, hemoglobin, leukocyte esterase, and protein; and (iii) to evaluate interference of ascorbic acid on the glucose, bilirubin, hemoglobin, and nitrite determination using 2 different dipsticks: iChem Velocity, Iris Diagnostics and Combur-10M, Roche Diagnostics. METHODS: Random urine specimens were included in the study. Comparability, accuracy, and ascorbic acid interference testing were performed. RESULTS: Obtained results have shown almost perfect agreement for all parameters between 2 dipsticks in samples with negative ascorbic acid. Agreement in samples with positive ascorbic acid was not acceptable for bilirubin, protein, nitrite, and hemoglobin. Accuracy was not acceptable for hemoglobin and leukocyte esterase on both dipsticks. Ascorbic acid interference examination has shown that intensity of interference differs between dipsticks. Ascorbic acid interferes with glucose, hemoglobin, nitrite, and bilirubin at different concentrations causing false-negative results. CONCLUSION: Obtained results indicate that it is necessary to determine diagnostic accuracy of used dipstick in order to define purpose of urinalysis. It is very important to choose dipstick with ascorbic acid indicator and to examine ascorbic acid impact on dipstick analytes independently of manufacturer claims.

Key Performance Indicators to Measure Improvement After Implementation of Total Laboratory Automation Abbott Accelerator a3600.

The aim of the study was to estimate improvement of work efficiency in the laboratory after implementation of total laboratory automation (TLA) by Abbott Accelerator a3600 in the laboratory with measuring different key performance indicators (KPIs) before and after TLA implementation. The objective was also to recommend steps for defining KPIs in other laboratories. For evaluation of improvement 10 organizational and/or technical KPIs were defined for all phases of laboratory work and measured before (November 2013) and after (from 2015 to 2017) TLA implementation. Out of 10 defined KPIs, 9 were successfully measured and significantly improved. Waiting time for registration of samples in the LIS was significantly reduced from 16 (9-28) to 9 (6-16) minutes after TLA (P < 0.001). After TLA all tests were performed at core biochemistry analyzers which significantly reduced walking distance for sample management (for more than 800 m per worker) and number of tube touches (for almost 50%). Analyzers downtime and engagement time for analyzers maintenance was reduced for 50 h and 28 h per month, respectively. TLA eliminated manual dilution of samples with extreme results with sigma values increment from 3.4 to >6 after TLA. Although median turnaround time TAT for potassium and troponin was higher (for approximately 20 min), number of outliers with TAT >60 min expressed as sigma values were satisfying (>3). Implementation of the TLA improved the most of the processes in our laboratory with 9 out of 10 properly defined and measured KPIs. With proper planning and defining of KPIs, every laboratory could measure changes in daily workflow.

Croatian laboratories have a good knowledge of the proper detection and management of hemolyzed, icteric and lipemic samples.

BACKGROUND: Endogenous interferences are an important source of biased laboratory results. Hemolysis, lipemia and icteria are the main source of endogenous interference in laboratory medicine. Accreditation according to ISO 15189 improves the overall quality of the laboratory procedures. The aim of our study was i) to assess the level of knowledge of Croatian medical biochemists about the proper detection and management of hemolysis, lipemia and icteria; and ii) to identify possible differences in the level of knowledge respective to the laboratory accreditation status. METHODS: An on-line self-report survey was carried out by the Working Group for Preanalytical Phase of the Croatian Society of Medical Biochemistry and Laboratory Medicine during April to May 2015. Survey included 14 statements (Q1-Q14) about procedures for samples with interferences and participants were asked to assess the degree of agreement with the statement using a 4-point Likert scale. RESULTS: The lowest level of knowledge was observed for statements Q10 (dealing with icteric sample; 40.9% participants agreed with the correct procedure), Q12 (allowable error for interference; 47.2%) and Q11 (dealing with lipemic sample; 60.1%). Almost all participants (97.4%) agreed that laboratories in Croatia should have a harmonized protocol for management of samples with interferences. Participants from accredited laboratories showed higher knowledge of hemolysis detection (p=0.031), rejection of hemolyzed sample (p<0.001), management of icteric samples (p=0.038) and allowable error for interferences (p=0.040). CONCLUSIONS: Croatian laboratories have a good knowledge of the proper detection and management of hemolyzed, icteric and lipemic samples. Accreditation is associated with higher knowledge about management of samples with interferences.

How to assess the quality of your analytical method?

Laboratory medicine is amongst the fastest growing fields in medicine, crucial in diagnosis, support of prevention and in the monitoring of disease for individual patients and for the evaluation of treatment for populations of patients. Therefore, high quality and safety in laboratory testing has a prominent role in high-quality healthcare. Applied knowledge and competencies of professionals in laboratory medicine increases the clinical value of laboratory results by decreasing laboratory errors, increasing appropriate utilization of tests, and increasing cost effectiveness. This collective paper provides insights into how to validate the laboratory assays and assess the quality of methods. It is a synopsis of the lectures at the 15th European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) Continuing Postgraduate Course in Clinical Chemistry and Laboratory Medicine entitled "How to assess the quality of your method?" (Zagreb, Croatia, 24-25 October 2015). The leading topics to be discussed include who, what and when to do in validation/verification of methods, verification of imprecision and bias, verification of reference intervals, verification of qualitative test procedures, verification of blood collection systems, comparability of results among methods and analytical systems, limit of detection, limit of quantification and limit of decision, how to assess the measurement uncertainty, the optimal use of Internal Quality Control and External Quality Assessment data, Six Sigma metrics, performance specifications, as well as biological variation. This article, which continues the annual tradition of collective papers from the EFLM continuing postgraduate courses in clinical chemistry and laboratory medicine, aims to provide further contributions by discussing the quality of laboratory methods and measurements and, at the same time, to offer continuing professional development to the attendees.

Reactogenicity and Peak Anti-RBD-S1 IgG Concentrations in Individuals with No Prior COVID-19 Infection Vaccinated with Different SARS-CoV-2 Vaccines.

OBJECTIVE: To investigate the association of immune response with vaccination adverse effects at peak anti-receptor-binding domain spike subunit 1 (anti-RBDS1) IgG after full vaccination with Comirnaty, Spikevax, or Vaxzevria. METHODS: Anti-RBDS1 IgG concentrations after vaccination were determined in healthy adults vaccinated with the Comirnaty, Spikevax, and Vaxzevria vaccines. The association of reactogenicity and peak antibody response after vaccination was tested. RESULTS: Anti-RBDS1 IgG values were significantly higher in the Comirnaty and Spikevax group, compared with the Vaxzevria group (P < .001). Fever and muscle pain were found to be significant independent predictors of peak anti-RBDS1 IgG in the Comirnaty and Spikevax groups (P = .03 and P = .02, respectively). The multivariate model, adjusted for covariates, showed that no association between reactogenicity and peak antibody concentrations was found in the Comirnaty, Spikevax, and Vaxzevria groups. CONCLUSIONS: No association between reactogenicity and peak anti-RBDS1 IgG after vaccination with the Comirnaty, Spikevax, and Vaxzevria vaccine was found.

Is the urinary neutrophil gelatinase-associated lipocalin concentration in children and adolescents with type 1 diabetes mellitus different from that in healthy children?

Introduction: Diabetic kidney disease (DKD) is one of the major microvascular complications of type 1 diabetes mellitus (T1DM). Some studies suggest that changes of renal tubular components emerge before the glomerular lesions thus introducing the concept of diabetic tubulopathy with urinary neutrophil gelatinase-associated lipocalin (uNGAL) as a potential marker of DKD. This concept was not confirmed in all studies. Materials and methods: In 198 T1DM patients with median age 15 years and diabetes duration over one year, an albumin/creatinine ratio (ACR) was determined and uNGAL measured in spot urine sample. Urine samples for ACR and uNGAL were also collected in the control group of 100 healthy children of similar age. Results: There was no significant difference in uNGAL concentration or uNGAL/creatinine between T1DM children and healthy subjects (6.9 (2.8-20.1) ng/mL vs 7.9 (2.9-21.0) ng/mL, P = 0.969 and 6.8 (2.2-18.4) ng/mg vs 6.5 (1.9-13.4) ng/mg, P = 0.448, respectively) or between T1DM subjects with albuminuria A2 and albuminuria A1 (P = 0.573 and 0.595, respectively). Among T1DM patients 168 (85%) had normal uNGAL concentrations, while in 30 (15%) patients uNGAL was above the defined cut-off value of 30.9 ng/mL. There was no difference in BMI, HbA1c and diabetes duration between patients with elevated uNGAL compared to those with normal uNGAL. Conclusions: We found no significant difference in uNGAL concentration or uNGAL/creatinine between T1DM children and healthy subjects or between albuminuria A2 and albuminuria A1 T1DM subjects. Therefore, uNGAL should not be recommended as a single marker for detecting diabetic kidney disease in children and adolescents.

YKL-40 as a biomarker in various inflammatory diseases: A review.

YKL-40 or Chitinase-3-Like Protein 1 (CHI3L1) is a highly conserved glycoprotein that binds heparin and chitin in a non-enzymatic manner. It is a member of the chitinase protein family 18, subfamily A, and unlike true chitinases, YKL-40 is a chitinase-like protein without enzymatic activity for chitin. Although its accurate function is yet unknown, the pattern of its expression in the normal and disease states suggests its possible engagement in apoptosis, inflammation and remodeling or degradation of the extracellular matrix. During an inflammatory response, YKL-40 is involved in a complicated interaction between host and bacteria, both promoting and attenuating immune response and potentially being served as an autoantigen in a vicious circle of autoimmunity. Based on its pathophysiology and mechanism of action, the aim of this review was to summarize research on the growing role of YKL-40 as a persuasive biomarker for inflammatory diseases' early diagnosis, prediction and follow-up (e.g., cardiovascular, gastrointestinal, endocrinological, immunological, musculoskeletal, neurological, respiratory, urinary, infectious) with detailed structural and functional background of YKL-40.

Visfatin is not associated with inflammatory markers in patients on hemodialysis.

BACKGROUND: Cardiovascular events are a major cause of death in patients with end-stage renal disease. Endothelial dysfunction represents a key event in atherosclerosis development and has been implicated in the pathophysiology of different forms of cardiovascular disease, including chronic kidney disease. In recent years, visfatin, a ubiquitous adipokine, has been described as a potent marker of endothelial inflammation and dysfunction. The aim of the study was to investigate the association of visfatin with well-known markers of inflammation and endothelial dysfunction. METHODS: Serum and plasma samples from 66 patients (40 males and 26 females) treated by hemodialysis were analysed for visfatin, fibrinogen, CRP, PAI-1 levels. Visfatin was determined by ELISA method while CRP, fibrinogen and PAL-1 were obtained by standard laboratory methods. RESULTS: We observed statistically significant correlation between visfatin level and fibrinogen (r = 0.51; p = 0.008) and the time on dialysis in female patients (r = 0.70; p < 0.001). PAI-1 and CRP did not correlate with visfatin in males nor in females. CONCLUSIONS: Visfatin is correlated with time on dialysis and with fibrinogen only in female dialysis patients. To confirm this, further studies are needed with a higher number of patients.

Serum Calprotectin Is a Valid Biomarker in Distinction of Bacterial Urinary Tract Infection From Viral Respiratory Illness in Children Under 3 Years of Age.

Background: Febrile illnesses in young children can be a major diagnostic challenge, despite the routine use of various laboratory markers. Recent advancements in the understanding of inflammatory processes have highlighted the role of calprotectin, a heterodimer consisting of S100A8 and S100A9 proteins, with many studies suggesting its clinical value as a biomarker of inflammation. This research aimed to evaluate the usefulness of serum calprotectin (sCal) as a biomarker of urinary tract infection (UTI), which was due to its high pooled prevalence and feasibility of urine culture as a diagnostic reference standard selected for a model of bacterial infection in children. Methods: Febrile children aged 0-36 months with suspected UTI based on positive urinalysis or viral respiratory tract infection were included. Children with significant bacteriuria in urine culture were labeled as cases (n = 58), while those with confirmed viral infection (n = 51), as well as those with suspected UTI but sterile urine culture who went on to develop symptoms consistent with viral respiratory infection (n = 7), were labeled as controls. sCal levels were determined by a commercial immunoassay. Conventional inflammation markers (C-reactive protein, procalcitonin, white blood cell count, absolute neutrophil count, and neutrophil percentage) were measured on the day of the clinical examination. Differences in measured inflammatory markers between cases and controls were analyzed with Mann-Whitney U-test. ROC analysis reported cut-off values with the best sensitivity and specificity to distinguish bacterial UTI from viral respiratory infection. Results: All analyzed inflammatory biomarkers, including sCal, were significantly higher in cases than in controls. Median concentration of sCal was 4.97 µg/mL (IQR 3.43-6.42) and 2.45 µg/mL (IQR 1.63-3.85) for cases and controls, respectively (p < 0.001). For identifying bacterial UTI, sensitivity and specificity of sCal were 77.6 and 69.0%, respectively, at an adjusted cut-off point of >3.24 µg/mL (AUC 80.2%). Conclusion: sCal could have substantial added value in the management of a child with fever and positive urinalysis and is a promising biomarker in distinction between bacterial UTI and viral respiratory causes of febrile illness in children under the age of 3 years.

The Increased Levels of Fecal Calprotectin in Children With Active Enthesitis Related Arthritis and MRI Signs of Sacroiliitis: The Results of a Single Center Cross-Sectional Exploratory Study in Juvenile Idiopathic Arthritis Patients.

Enthesitis related arthritis (ERA) is a specific subtype of juvenile idiopathic arthritis (JIA), often regarded as an undifferentiated form of juvenile spondyloarthritis (jSpA). While gut is increasingly recognized as origin and/or target of inflammation in adult onset spondyloarthritis (SpA), the incidence of gut involvement in ERA patients is largely unknown. The aim of this study was to measure the concentration of fecal calprotectin (fCAL), a surrogate marker of gut inflammation, in patients with different subtypes of JIA, as well as to correlate the results with various demographic, clinical, laboratory, imaging, and treatment characteristics. The cross-sectional exploratory study involving 71 patients with ERA, other forms of JIA and children complaining musculoskeletal symptoms was therefore conducted. Along with fCAL assessment, a detailed clinical and laboratory examination was performed, including the calculation of a composite disease activity scores. Moreover, MRI of the sacroiliac joints was performed in all ERA and other patients complaining of low back pain. The median concentration of fCAL was highest in ERA patients (33.2 mg/kg, p = 0.02), with a significant difference between those with inactive and active disease (20.0 vs. 57.4, p = 0.01), as well as those with and without MRI signs of sacroiliitis (22.6 vs. 54.3, p = 0.04). The fCAL did not differ depending on the NSAID use (23 vs. 20, p = 0.18), although weak correlation was observed with the treatment duration (r = 0.25, p = 0.03). In conclusion, our findings indicate that a parallel inflammation in musculoskeletal system and gut can occur not just in adults with SpA, but in children with ERA as well.

Comparison of diagnostic accuracy for eight SARS-CoV-2 serological assays.

INTRODUCTION: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serological tests have been suggested as an additional diagnostic tool in highly suspected cases with a negative molecular test and determination of seroprevalence in population. We compared the diagnostic performance of eight commercial serological assays for IgA, IgM, and IgG antibodies to the SARS-CoV-2 virus. MATERIALS AND METHODS: The comparison study was performed on a total of 76 serum samples: 30 SARS-CoV-2 polymerase chain reaction (PCR)-negative and 46 SARS-CoV-2 PCR-positive patients with asymptomatic to severe disease and symptoms duration from 3-30 days. The study included: three rapid lateral flow immunochromatographic assays (LFIC), two enzyme-linked immunosorbent assays (ELISA), and three chemiluminescence immunoassays (CLIA). RESULTS: Agreement between IgM assays were minimal to moderate (kappa 0.26 to 0.63) and for IgG moderate to excellent (kappa 0.72 to 0.92). Sensitivities improved with > 10 days of symptoms and were: 30% to 89% for IgM; 89% to 100% for IgG; 96% for IgA; 100% for IgA/IgM combination; 96% for total antibodies. Overall specificities were: 90% to 100% for IgM; 85% to 100% for IgG; 90% for IgA; 70% for IgA/IgM combination; 100% for total antibodies. Diagnostic accuracy for IgG ELISA and CIA assays were excellent (AUC ≥ 0.90), without significant difference. IgA showed significantly better diagnostic accuracy than IgM (P < 0.001). CONCLUSION: There is high variability between IgM assays independently of the assay format, while IgG assays showed moderate to perfect agreement. The appropriate time for testing is crucial for the proper immunity investigation.