First Results of an External Quality Assessment (EQA) Scheme for Molecular, Serological and Antigenic Diagnostic Test for SARS-CoV-2 Detection in Lombardy Region (Northern Italy), 2020-2022.

For diagnosing SARS-CoV-2 infection and for monitoring its spread, the implementation of external quality assessment (EQA) schemes is mandatory to assess and ensure a standard quality according to national and international guidelines. Here, we present the results of the 2020, 2021, 2022 EQA schemes in Lombardy region for assessing the quality of the diagnostic laboratories involved in SARS-CoV-2 diagnosis. In the framework of the Quality Assurance Programs (QAPs), the routinely EQA schemes are managed by the regional reference centre for diagnostic laboratories quality (RRC-EQA) of the Lombardy region and are carried out by all the diagnostic laboratories. Three EQA programs were organized: (1) EQA of SARS-CoV-2 nucleic acid detection; (2) EQA of anti-SARS-CoV-2-antibody testing; (3) EQA of SARS-CoV-2 direct antigens detection. The percentage of concordance of 1938 molecular tests carried out within the SARS-CoV-2 nucleic acid detection EQA was 97.7%. The overall concordance of 1875 tests carried out within the anti-SARS-CoV-2 antibody EQA was 93.9% (79.6% for IgM). The overall concordance of 1495 tests carried out within the SARS-CoV-2 direct antigens detection EQA was 85% and it was negatively impacted by the results obtained by the analysis of weak positive samples. In conclusion, the EQA schemes for assessing the accuracy of SARS-CoV-2 diagnosis in the Lombardy region highlighted a suitable reproducibility and reliability of diagnostic assays, despite the heterogeneous landscape of SARS-CoV-2 tests and methods. Laboratory testing based on the detection of viral RNA in respiratory samples can be considered the gold standard for SARS-CoV-2 diagnosis.

Celiac Disease Diagnosis Without Biopsy: Is a 10× ULN Antitransglutaminase Result Suitable for a Chemiluminescence Method?

OBJECTIVES: 2012 European Society of Pediatric Gastroenterology, Hepatology and Nutrition guidelines allow to establish a celiac disease diagnosis without duodenal biopsy in symptomatic pediatric patients with antitissue transglutaminase (anti-tTG) titers >10 times the upper limit of normal. For some years now, new chemiluminescence immunoassays have been made available: it is important to establish the clinical performance of anti-tTG and to determine the cut-off best suited to predict Marsh ≥2 to avoid gastrointestinal endoscopy not only in children, but also in the adult population. METHODS: A total of 2565 patients performed duodenal biopsy from July 2012 to September 2016; we selected all the patients who had undergone QUANTA Flash anti-tTG immunoglobulin A (IgA) within -3 months of duodenal biopsy and before the start of gluten-free diet. A total of 827 patients fulfilled the criteria for selection. RESULTS: Using a cut-off of 20 chemiluminescent unit (CU; area under the curve: 0.995), sensitivity, specificity, positive, and negative predictive value were 98.2%, 98.4%, 97.9%, and 98.6%, respectively. For the correlation with Marsh ≥2, in the pediatric population, positive predictive values (PPV) were 92.1%, 99%, and 100% at 200 CU (10×), 560 CU (28×), and 1000 CU (50×), respectively. In the adult population PPV was 94.2%, 98.2%, and 100% at 200 CU (10×), 350 CU (15×), and 400 CU (20×). CONCLUSIONS: Sensitivity, specificity, positive, and negative predictive value of QUANTA Flash h-tTG IgA were excellent. The cut-off providing an optimized PPV for histological lesions compatible for celiac disease (Marsh ≥2) for the QUANTA Flash h-tTG IgA is 350 CU (15×) in adult and 560 CU (28×) in children.

Validation rules for blood smear revision after automated hematological testing using Mindray CAL-8000.

BACKGROUND: This article was aimed to test the use of validation rules for blood smear review after automated hematological testing using Mindray CAL-8000 (two hematological analyzers and one autoslider). METHODS: This study was based on 1013 peripheral blood samples (PB) referred for routine hematological testing. Results of testing on CAL-8000 were analyzed using both locally derived and International Consensus Group for Hematology (ICGH) validation rules, and then compared with data obtained by optical microscopy (OM). A workflow analysis was also completed. RESULTS: The overall agreement with locally derived and ICGH criteria was 91% and 85%, but a higher sensitivity was observed for locally derived criteria (0.97 vs 0.95). The percentage of false negative and false positive samples was 2.1% and 7.1% using ICGH criteria, and was 1.4% and 14% using locally defined rules. The throughput of CAL-8000 system was 208 samples/h, with a percentage of OM analysis comprised between 14% and 17%, and sensitivity of 0.97. As regards personnel activity, we estimated 0.8 full-time equivalent (FTE) of technical staff and 0.7 FTE of personnel for clinical validation of data and blood smear review. CONCLUSION: These results show that customization of validation rules is necessary for enhancing the quality of hematological testing and optimizing workflow.

Clinical significance of cell population data (CPD) on Sysmex XN-9000 in septic patients with our without liver impairment.

BACKGROUND: This study evaluated the clinical significance of cell population data (CPD) parameters obtained on Sysmex XN-9000 in septic patients admitted to intensive care unit (ICU) and stratified according to liver function. METHODS: The study population consisted in 84 patients, 44 of whom did not develop sepsis (NS), whereas the remaining 40 developed sepsis (SE) (n=24) or septic shock (SS) (n=16). Two hundred ostensibly healthy blood donors [healthy subjects (HS)], undergoing routine blood testing before a regular blood donation, were studied. RESULTS: Except for neutrophils and lymphocytes cell size (NE-FCS and LY-Z), all other CPD values were significantly different in ICU patients compared to HS. Neutrophils and monocytes fluorescence intensity (NE-SFL and MO-X) values were significantly higher in SS compared to sepsis and not develop sepsis patients. The value of many parameters was also different according to liver function. Overall, MO-X and neutrophils fluorescence intensity (NE-SFL) exhibited the best performance for diagnosing sepsis in all patients (AUC, 0.75 and 0.72), as well as in those with (AUC, 0.95 and 0.89) or without (AUC, 0.72 for both) liver impairment. These parameters were also significantly correlated with Sequential Organ Failure Assessment (SOFA) score. CONCLUSIONS: This study suggested that some novel CPD parameters (namely NE-SFL and MO-X) may provide useful information for diagnosis and management of sepsis.

Cell Population Data and reflex testing rules of cell analysis in pleural and ascitic fluids using body fluid mode on Sysmex XN-9000.

BACKGROUND: Although optical microscopy (OM) remains the reference technique for analysis of ascitic (AF) and pleural (PF) fluids, novel hematological analyzers are equipped with modules for body fluid (BF) analysis. This study was aimed to analyze the performance of XN-BF module in Sysmex XN-9000, and to develop validation rules for automated cell counts in BFs. METHODS: The evaluation of XN-BF module included assessment of carryover, Limit of Blank (LoB), Limit of Detection (LoD), Limit of Quantitation (LoQ), linearity, data comparison with OM, and development of rules for assisting the validation of automated analysis of BFs and activating reflex testing. RESULTS: The carryover was negligible. The LoB, LoD, LoQ and linearity were always excellent. The comparison with OM was characterized by Pearson's correlations ranging from r=0.50 to r=0.99 (p<0.001), modest bias and high diagnostic concordance (Area Under the Curve between 0.85 and 0.99). The use of instrument-specific cut-offs further increased diagnostic concordance. The implementation of reflex testing rules based on XN-BF data increased sensitivity and specificity of BFs classification to 0.98 and 0.95. CONCLUSIONS: Our results suggest that the XN-BF module on Sysmex-9000 may be a suitable alternative to OM for screening BF samples, especially when specific validation rules are used.

Extended leukocyte differential count and C-reactive protein in septic patients with liver impairment: diagnostic approach to evaluate sepsis in intensive care unit.

BACKGROUND: Sepsis is still a major cause of death in intensive care units (ICUs) worldwide. Patients with liver impairment express an imbalanced cytokine response which alters common sepsis biphasic nature. Cytokines measurement is expensive, often unavailable, whereas leukocytes (WBC) evaluation performed through hematology analyzers can provide a practical strategy for monitoring inflammatory response. METHODS: A total of 200 healthy subjects (HS) and 84 patients (18 with, 66 without liver impairment) admitted to ICU, were assessed for International Sepsis Definitions, Sequential Organ Failure Assessment (SOFA) and Model for End-Stage Liver Disease (MELD) scores. We tested 1,022 peripheral blood samples using Sysmex XN-9000, estimating diagnostic accuracy of leukocyte differential count and nontraditional parameters through receiver operating characteristics (ROC) curves analysis compared to clinical classification. RESULTS: Median value of all-leukocyte parameters was different in ICU patients compared to HS. Leukocytes, neutrophils (NE) and immature granulocytes (IGs) in sepsis and septic shock (SS) were higher than no sepsis (NS), with an area under the curve: 0.81, 0.82 and 0.78 respectively. Lymphocytes (LY) and monocytes (MO) were significantly associated with liver impairment. CONCLUSIONS: Diagnostic accuracy of all-leukocyte parameters may provide valuable information for diagnosis and follow-up of sepsis in ICU patients, especially those with liver impairment.

Pediatric reference values for urine particle quantification by using automated flow cytometer: results of a multicenter study of Italian urinalysis group.

OBJECTIVES: The purpose of this Italian multicenter study was to define pediatric upper reference values for urine particle quantification by using automated flow cytometry. DESIGN AND METHODS: Four hospital-based clinical laboratories participated in this multicenter investigation, which included a total study population of 161 Italian children aged from 1 to 12years. Two laboratories used Sysmex UF-100 and analyzed 86 children, whereas the other two used Sysmex UF-1000i and analyzed 75 subjects. Particle quantification included the analysis of white blood cells (WBC), red blood cells (RBC), squamous epithelial cells (EC), transitional epithelial cells (TC), casts (CAST) and bacteria (BACT). RESULTS: The upper reference values in subjects tested with the Sysmex UF-100 were 9.7WBC/µL, 10.1RBC/µL, 7.5EC/µL, 2.5TC/µL, 0.7CAST/µL and 3090BACT/µL, whereas the upper reference values in subjects tested with the Sysmex UF-1000i were 10.5WBC/µL, 8.3RBC/µL, 7.2EC/µL, 2.9TC/µL, 0.7CAST/µL and 48BACT/µL. No statistically significant differences between genders were found in the value distribution of any of the parameters tested. Similarly, no statistically significant differences were observed between the two urine analyzers, except for BACT. CONCLUSIONS: Automated analysis of urine particles appears a suitable means to optimize the workflow of routine urinalysis of children specimens. The upper reference limits for pediatric subjects obtained in this study were comparable to those previously reported in the literature, with no significant differences between genders and analyzers.