Passing-Bablok Regression Analysis Research Articles

Statistical comparison for assessing agreement between two mass spectrometric methods for the analysis of polychlorinated dibenzo-p-dioxins and furans (PCDDs/Fs) in contaminated soils

A gas chromatography coupled to high-resolution mass spectrometry (GC-HR/MS) has been used as the standard method for the quantification of polychlorinated dibenzo-p-dioxins and furans (PCDDs/Fs), which are regulated at screening and action levels in the environment. However, several alternative methods have been attempted due to the disadvantage of its high cost. Although a gas chromatography with triple quadrupole mass spectrometry (GC-QqQ-MS/MS) has been used in a wide variety of sample matrices, showing that they are interchangeable, there has been a lack of comprehensive studies on statistical agreement with GC-HR/MS. In this study, a pairwise comparison of the total concentrations of PCDDs/Fs in 90 soil field samples obtained by two mass spectrometric methods was performed using the Passing-Bablok (P&B) regression and Bland-Altman (B&A) analysis for the method comparison. According to the result of the B&A analysis, the concentration range of PCDDs/Fs was between 98.2 and 1760 pg/g showed good agreement between two methods at the 95 % confidence level (CL). Although there was a large discrepancy between the two methods in the low concentrations (<16.5 pg/g of PCDDs/Fs), this result was similar to the P&B regression analysis. As the verification results by B&A and P&B regression analysis, the interchangeable concentration range between the two methods was confirmed to be adequate for the monitoring of PCDDs/Fs regulating levels in soils.

A novel integrated lateral flow immunoassay platform for the detection of cardiac troponin I using hierarchical dendritic copper-nickel nanostructures

Cardiac troponin I (cTnI) is a critical biomarker for the diagnosis of acute myocardial infarction (AMI). Herein, we report a novel integrated lateral flow immunoassay (LFIA) platform for highly sensitive point-of-care testing (POCT) of cTnI using hierarchical dendritic copper-nickel (HD-nanoCu-Ni) nanostructures. The electrodeposited HD-nanoCu-Ni film (∼22 μm thick) on an ITO-coated glass substrate exhibits superior capillary action and structural integrity. These properties enable efficient sample transport and antibody immobilization, making it a compelling alternative to conventional multi-component paper-based LFIA test strips, which are often plagued by structural fragility and susceptibility to moisture damage. The biofunctionalized HD-nanoCu-Ni substrates were laser-etched with lateral flow channels, including a sample loading/conjugate release zone, a test zone, and a control zone. Numerical simulations were used to further optimize the design of these channels to achieve optimal fluid flow and target capture. The HD-nanoCu-Ni LFIA device utilizes a fluorescence quenching based sandwich immunoassay format using antibody-labeled gold nanoparticles (AuNPs) as quenchers. Two different fluorescent materials, fluorescein isothiocyanate (FITC) and CdSe@ZnS quantum dots (QDs), were used as background fluorophores in the device. Upon the formation of a sandwich immunocomplex with cTnI on the HD-nanoCu-Ni device, introduced AuNPs led to the fluorescence quenching of the background fluorophores. The total assay time was approximately 15 min, demonstrating the rapid and efficient nature of the HD-nanoCu-Ni LFIA platform. For FITC, both inner filter effect (IFE) and fluorescence resonance energy transfer (FRET) contributed to the AuNP-mediated quenching. In the case of CdSe@ZnS QDs, IFE dominated the AuNP-induced quenching. Calibration curves were established based on the relationship between the fluorescence quenching intensity and cTnI concentration in human serum samples, ranging from 0.5 to 128 ng/mL. The limits of detection (LODs) were determined to be 0.27 ng/mL and 0.40 ng/mL for FITC and CdSe@ZnS QDs, respectively. A method comparison study using Passing-Bablok regression analysis on varying cTnI concentrations in human serum samples confirmed the equivalence of the HD-nanoCu-Ni LFIA platform to a commercial fluorescence cTnI LFIA assay kit, with no significant systematic or proportional bias observed.

To Determine the Accuracy and Reliability of Broselow Tape in Comparison with Actual Weight and Advance Pediatric Life Support Formula Weight Assessment among the Pediatric Population Presenting to Emergency Department of a Low Income Setting

Background: Near precise weight assessment among sick pediatric patients remains a dilemma and conventionally accepted weight assessment methods, in busy ED might be inaccurate or unreliable. Children have different weights at different ages, and accurate/precise weight measurement is of utmost importance for weight-related dose calculation of drugs/fluids, equipment sizes, an accurate dose of electrical currents during cardiac shock, etc. Several weight estimation methods are available and are dependent on the child's age, length, or both. However, length or length-and-age-based methods may have greater accuracy than merely age-based, still precise weight measurement while children are recumbent (length) has its own challenges. Objective: We determined the accuracy and reliability of BT by comparing it with actual weight and advanced pediatric life support formula (APLS) among the pediatric population presenting to the emergency department. Methods: This was a single-center, cross-sectional study design. This study was conducted at pediatric emergency of an urban tertiary care hospital after ethics committee approval and written consent from parents/caregivers during July 2021- June 22. Pediatric patients aged 1 month to 12 years, weight 3-36 kg, and height 46.5-142.5 cm on BT were included. Actual weight was measured on a standard weighing machine. We use Broselow pediatric emergency tape (2017 edition), APLS formula was also used to measure the estimated weight by using the age provided by parents. Descriptive analysis, mean and standard deviation were calculated, frequencies and percentages were calculated for categorical variables. Cronbach’s alpha and Passing-Bablok regression analysis was applied to assess the reliability and identify systematic biases between actual body weights with estimated BT. Bland–Altman analysis was also performed to measure the precision, accuracy, and bias. Results: 250 children were included with equal gender distribution and were divided in to three categories as per the weight estimation by BT in to &lt;10 kg (n=58, 23.2%), 10-18 kg (n=151, 60.4%) and &gt;18 kg (n=41, 16.4%). The mean age was 5.26 (±2.37) years, majority of children were below 5 years of age (n=144, 58%). Positive agreement between BT weight with actual weight and other formulas in weight category of &lt;10 kg, however as weight increases from 10 kg, onward results are not significant. Passing and Bablok Regression analysis showed a positive correlation between the estimated and actual (AW) body weight (r=0.9280, p&lt;0.001) and accuracy (r2=0.929), and the accuracy of BT weight decreases with the increasing weight of children. Similarly, 95% agreement limit and mean biased was 0.465 to 1.113 and 0.789±2.602 between BT and APLS, BT with AW was -0.50 to -0.28 and -0.39±0.885. Comparing and correlating weight assessment of APLS formula vs LF and TF didn't show significance with a p-value of 0.041 and 0.034 respectively. Bland-Altman plot between BT measurement with AW demonstrates a bias equal to 1.096 kg with a limit of 0.870 to 1.815. Conclusion: BT may be an accurate and time bound method of weight measurement as compared to other methods of weight estimation, however the accuracy of BT may be adversely affected with age exceeding 95 months and weight &gt;26 kg. BT may be safely used in the younger pediatric population. Health care professionals may consider this information while using BT to estimate weight for pediatric resuscitation, however, this is a single center hospital based study with limited cases, we recommend to have a large scale community based study or a census before to generalize these results to general population.

Fluorescence-Based Lateral Flow Immunoassay for Quantification of Infliximab: Analytical and Clinical Performance Evaluation.

Therapeutic drug monitoring of infliximab (IFX) can improve treatment outcomes; however, the temporal gap between drug concentration monitoring and subsequent availability restricts its practical application. To address this issue, an automated monitoring method, AFIAS IFX, was developed to rapidly and accurately analyze IFX concentration in blood. The analytical and clinical performances of this method were assessed to establish its clinical utility. The analytical performance of AFIAS IFX was evaluated according to Clinical and Laboratory Standard Institute guidelines. For clinical validation, AFIAS IFX was compared with 3 established enzyme-linked immunosorbent assay kits (LISA TRACKER, RIDASCREEN, and ImmunoGuide) using 100 consecutive samples from 28 patients treated with IFX. Passing-Bablok regression and Bland-Altman analyses were performed to compare the methods. The detection and quantification limits of AFIAS IFX were 0.12 and 0.20 mcg/mL, respectively. Furthermore, AFIAS IFX analyzed samples within 10 minutes for concentrations up to 50 mcg/mL, exhibiting reproducibility (coefficient of variation [CV] ≤7.8%) and accuracy (recovery 98%-101%) with serum, plasma, and whole blood samples. Clinically, it exhibited a good correlation with the 3 established enzyme-linked immunosorbent assay kits. For patients treated with Remicade (IFX), the Passing-Bablok regression slope was 1.001-1.259, with a mean difference of -1.48 to 0.28 mcg/mL. For patients treated with CT-P13, the Passing-Bablok regression slope was 0.974-1.254, with a mean difference of -2.44 to 0.15 mcg/mL. AFIAS IFX, a novel fluorescence-based lateral flow assay, exhibited excellent performance in analyzing IFX trough levels and is a potentially powerful tool for therapeutic drug monitoring in clinical settings, with opportunities for further development.

Stent sizing by coronary CT angiography compared with optical coherence tomography

BackgroundCoronary CT angiography (CCTA) is well-established for diagnosis and stratification of coronary artery disease (CAD). Its usefulness in guiding percutaneous coronary interventions (PCI) and stent sizing is unknown. MethodsThis is a sub-analysis of the Precise Percutaneous Coronary Intervention Plan (P3) study (NCT03782688). We analyzed 65 vessels with matched CCTA and pre-PCI optical coherence tomography (OCT) assessment. The CCTA-guided stent size was defined by the mean distal reference lumen diameter rounded up to the nearest stent diameter. The OCT lumen-guided stent size was the mean distal reference lumen diameter rounded to the closest stent diameter. The agreement on stent diameters was determined with Kappa statistics, Passing–Bablok regression analysis, and the Bland-Altman method. ResultsThe distal reference lumen diameter by CCTA and OCT were 2.75 ​± ​0.53 ​mm and 2.72 ​± ​0.55 ​mm (mean difference 0.06, limits of agreement −0.7 to 0.82). There were no proportional or systematic differences (coefficient A 1.06, 95% CI 0.84 to 1.3 and coefficient B −0.22, 95% CI -0.83 to 0.36) between methods. The agreement between the CCTA and OCT stent size was substantial (Cohen's weighted Kappa 0.74, 95% CI 0.64 to 0.85). Compared to OCT stent diameter, CCTA stent size was concordant in 52.3% of the cases; CCTA overestimated stent size in 20.0% and underestimated in 27.7%. ConclusionCCTA accurately assessed the reference vessel diameter used for stent sizing. CCTA-based stent sizing showed a substantial agreement with OCT. CCTA allows for PCI planning and may aid in selecting stent diameter.

A validated method for simultaneous quantification of four antiretrovirals in dried blood spot and plasma using LC-MS/MS: Application to efavirenz therapeutic drug monitoring in pregnant patients

IntroductionThe specific physiological background induced by pregnancy leads to significant changes in maternal pharmacokinetics, suggesting potential variability in plasma concentrations of antiretrovirals. Pregnant HIV patients exposed to subtherapeutic doses, particularly in the last trimester of the pregnancy, have higher chances to transmit the infection to their children. Therefore, the therapeutic drug monitoring of antiretrovirals in HIV pregnant patients would be of great value. ObjectivesThis study aimed to develop and validate a sensitive liquid chromatograph tandem mass spectrometry (LC-MS/MS) method for simultaneous quantification of efavirenz, raltegravir, atazanavir, and ritonavir in dried blood spots (DBS) and plasma. Design and MethodsThe analytes were extracted from the DBS punch and plasma with a mixture of methanol:zinc sulfate 200 mM (50:50, v/v) and 100 % methanol, respectively. For the chromatographic separation a Shim-pack® C18, 4.6 mm × 150 mm, 5 μm column was used. Detection was performed in a 3200-QTRAP® mass spectrometer, with a run time of 6 min. ResultsThe assay was linear in the range of 15–1,000 ng/mL for raltegravir, 50–10,000 ng/mL for both atazanavir and ritonavir, 50–5,000 ng/mL for efavirenz. Precision and accuracy at these concentrations were less than 15 % for all analytes. Raltegravir, atazanavir, and ritonavir were stable for seven days at 23 °C and 40 °C, whereas efavirenz was stable for twenty-four hours at the same conditions. ConclusionsThe method was successfully applied to quantify efavirenz in DBS samples obtained from HIV-1 infected pregnant volunteers under antiretroviral therapy. The concentrations of efavirenz in DBS and plasma were comparable according to Passing-Bablok regression and Bland-Altman analysis.

Point-of-Care Capillary Compared to Venous Bilirubin Measurement in Neonates

AbstractWe aimed to evaluate the agreement between the point-of-care (POC) capillary bilirubin measurement with POC venous samples and the reference laboratory measurement. We conducted a prospective comparative study, including neonates ≥ 34 weeks of gestational age, and ≥ 72 h of age. The agreement between POC (Calmark Neo-Bilirubin, Sommargatan, Karlstad, Sweden) capillary, POC venous, and laboratory venous bilirubin was examined with the Bland–Altman plot and the Passing-Bablok regression analyses. The mean bilirubin was 13.54 (2.79) mg/dL in the POC capillary samples, 13.45 (2.69) mg/dL in the POC venous samples, and 12.68 (2.33) mg/dL in reference samples. Bland–Altman plots showed optimal agreement between the POC capillary and venous methods, and with the reference venous method. The bias between the POC capillary and venous methods was 0.094 [levels of agreement (− 3.118)− 3.306], between the POC capillary and the reference venous methods 0.865 [levels of agreement (− 2.283)− 4.014], and between the POC venous and the reference venous methods 0.771 [levels of agreement (− 1.814)− 3.357]. The POC capillary and venous bilirubin levels were in optimal agreement with each other, and with the reference venous measurements, supporting the POC Calmark Neo-Bilirubin capillary measurement as an alternative for a less-invasive, more rapid evaluation of bilirubin.

Mathematical model for assessing glycemic control in type 2 diabetes mellitus.

Glycated hemoglobin (HbA1c) and glycated albumin (GA) are vital markers for assessing glucose control in diabetes. This cross-sectional study involving 901 diagnosed type 2 diabetics aimed to compare calculated HbA1c, using the formula HbA1c = 2.6 + 0.03 x FBS (mg/dL), with directly measured HbA1c. Simultaneously, the study assessed the agreement between the two methods through regression analysis and explored correlations with various measures of glycemic control. The non-parametric Kolmogorov-Smirnov test indicated a non-normal data distribution, prompting appropriate statistical tests. Spearman's correlation coefficient revealed a strong correlation of calculated HbA1c, calculated GA, and estimated average glucose with measured parameters. Wilcoxon rank sum test indicated a significant difference between directly measured and calculated HbA1c (Z -9.487033, p < 0.0001). Passing Bablok regression analysis showed a significant deviation from linearity. Despite the potential cost benefits in resource-poor settings, caution is advised regarding interchangeable use of calculated and directly measured HbA1c in clinical decision-making. Data shows the importance of robust analytical methods in glycemic control assessment, offering insights for managing type 2 diabetes mellitus.

Comparison of Friedewald, Martin/Hopkins, and Sampson formulae with direct LDL measurement in hyperlipidaemic and normolipidaemic adults

&#x0D; ABSTRACT&#x0D; Objective: In our study, we aimed to compare and validate the performance of the Friedewald, Martin/Hopkins, and Sampson formulae with direct LDL-C measurement.&#x0D; Material and Methods: The study was a retrospective investigation which by the Department of Medical Biochemistry of the Ankara Training and Research Hospital between 1 January 2021 and 31 December 2022. Our study evaluated the results of 6297 patients aged 18-99 years who underwent cholesterol panel TC, TG, HDL-C and direct LDL-C in our laboratory. Estimated LDL-C calculated according to Friedewald, Martin/Hopkins, and Sampson formulae. &#x0D; Results: All three formulae showed a stronger positive correlation with d-LDL-C (0.905, 0.897, and 0.886, respectively, for all data, p&lt;0.001). In addition, when we compared the total median difference (1st-3rd quartile) of all formulae, it was it was -0.69 (-1.62-0.39) for Friedewald, 0.034 (-0.74 -1.14) for Martin/Hopkins and -0.40 (-1.19-0.55) for Sampson. According to Passing Bablok regression analyses, the intercept was determined as -0.97 (95% CI = -1.01 to -0.93), 0.41 (95%=0.37 to 0.44) and -0.05 (-0.08 to -0. 03) and slopes were calculated as 1.083 (95% CI = 1.07-1.09), 0.88 (0.88 to 0.89) and 0. 90 (95% = 0.89 to 0.90) for Friedewald, Martin/Hopkins and Sampson, respectively.&#x0D; Conclusions: Our findings suggest that Martin/Hopkins formula indicated a better performance than Friedewald and Sampson formulae. We figured out utilizing the Martin/Hopkins formula as a good alternative for estimated LDL-C in Turkish adults. &#x0D;

A comparison study between the Siemens ADVIA 120 and manual method for the differential white blood cell count in goats.

Although widely used, the ADVIA 120 hematology analyzer has not been previously validated for determining the differential leukocyte count in goats. The aim of this study was to compare the differential leukocyte counts provided by the ADVIA 120 (A-diff) and the manual method (M-Diff) in goats. EDTA blood samples that were analyzed within 4 h of collection were used in the study. The following exclusion criteria were applied: inappropriately filled tubes or tubes containing clots, erroneous ADVIA peroxidase cytograms, and blood smears of poor quality. The A-Diff was compared with the M-Diff performed by two independent observers on 200 leukocytes. Forty samples were included after previously excluding eight samples. The correlation between the A-Diff and M-Diff was very strong for eosinophils (r = .870, p < .001) and strong for lymphocytes (r = .796, p < .001) and neutrophils (r = .730, p < .001), while no significant correlation was observed for monocytes (r = .026, p = .872). The Passing-Bablok regression analyses revealed statistically significant constant errors for neutrophils (5.83%; 95% confidence interval [CI]: 0.41%, 12.18%) and eosinophils (1.89%; 95% CI: 1.17%, 2.71%). Bland-Altman analyses showed a statistically significant negative bias for lymphocytes (-5.0%) and a statistically significant positive bias for eosinophils (2.2%). The very low basophil percentages precluded a meaningful method comparison. The ADVIA 120 overall demonstrated good performance for the differential WBC count in goats under the conditions of this study. Therefore, it can be considered suitable for routine hematologic screening in goats. Nonetheless, it should be emphasized that any abnormal result should be confirmed with a blood smear evaluation.

Abbott D-dimer assay: analytical performance and diagnostic accuracy in management of venous thromboembolism

This study aimed to assess analytical characteristics and diagnostic accuracy in management of venous thromboembolism (VTE) in the Emergency Department (ED) of the Abbott D-dimer assay applied on the Alinity c clinical chemistry analyzer (Abbott Laboratories, Chicago, IL) compared to the INNOVANCE D-dimer assay (Siemens Healthineers, Marburg, Germany). Precision was determined at three concentration levels following the CLSI EP15-A3 protocol. Method comparison and diagnostic accuracy were assessed using samples obtained from 85 patients who were referred for diagnostic imaging and D-dimer testing due to clinically suspected VTE. Within-run coefficients of variation (CVs) were 3.0%, 0.5% and 0.5% at D-dimer concentrations of 0.54, 1.42 and 2.68 mg/L FEU, while respective between-run CVs were 2.0%, 3.4% and 2.7%, hence fulfilling the desirable biological variation criteria for imprecision (<12.6%). Passing–Bablok regression analysis yielded a small proportional difference between the two compared assays (y = 1.09 (95% confidence interval (CI): 1.01–1.18) x + 0.09 (95%CI: –0.09 to 0.16)), while Bland–Altman analysis showed significant negative absolute (–0.6 mg/L FEU, 95%CI: –0.9 to −0.3) and relative mean bias (–14.1%, 95%CI: –20.3 to −7.9). Spearman’s ρ was 0.979 (95%CI: 0.967–0.986). Inter-assay agreement relative to the cut-off was 92% (kappa coefficient = 0.547 (95%CI: 0.255–0.839)). Diagnostic sensitivity, specificity, positive and negative predictive values of the Abbott assay were 100%, 9.2%, 25.3% and 100%, respectively, compared to the following data for the INNOVANCE assay: 95.0%, 15.4%, 25.7% and 90.9%. Abbott D-dimer assay has shown excellent analytical precision, high comparability with the INNOVANCE D-dimer and high NPV at manufacturer’s cut-off.

Comparable analysis of six immunoassays for carcinoembryonic antigen detection

ObjectiveThis study aimed to assess the current status of carcinoembryonic antigen (CEA) detection. We evaluated the correlation, consistency, and comparability of CEA results among six automated immunoassays, and combined with the results of CEA trueness verification of the Beijing Center for Clinical Laboratories (BCCL) for further analysis. MethodsAbbott Architect i2000, Beckman DxI800, Roche Cobas E601, Diasorin Liaison XL, Maccura IS1200, and Autolumo A2000 were used to detect 40 individual serum CEA samples. Taking the optimal analytical quality specifications calculated from data on biological variation as the evaluation criterion. Passing-Bablok regression and Bland-Altman analysis were performed between each assay and all-assays median values to evaluate the correlation and relative difference. The concordance correlation coefficient (CCC) was used for consistency analysis. Additionally, the trueness verification program used samples at three concentration levels to assess the bias, coefficient of variation (CV), and total error (TE) between the average measured values and the target value. ResultsThe Spearman's rank correlation coefficient (rs) was ≥0.996 and the CCC ranged between 0.9448 and 0.9990 for each assay vs. all-assays median. Considering the all-assays median value of each sample as a reference, there were proportional and systematic differences according to the Passing-bablok regression analysis. The relative difference of the four assays (Abbott Architect i2000, Autolumo A2000, Diasorin Liaison XL, and Maccura IS1200) met the optimal analytical quality specifications. On the other hand, Beckman DxI800 (13.2 %) and Roche Cobas E601 (−9.0 %) were only able to fulfill the desirable analytical quality specifications. The average pass rates for bias, CV, and TE of the trueness verification program were 80 %, 98 %, and 96 %, respectively. ConclusionsThe six automated immunoassays vs. all-assays median have a good correlation in CEA detection. However, there is a lack of comparability of CEA results. Further improvements are needed in harmonization among CEA detections.

Human papillomavirus (HPV) DNA methylation changes in HPV-associated head and neck cancer.

Despite the rising incidence, currently, there are no early detection methods for HPV-driven HNC (HPV-HNC). Cervical cancer studies suggest that HPV DNA methylation changes can be used as a biomarker to discriminate cancer patients from HPV-infected individuals. As such, this study was designed to establish a protocol to evaluate DNA methylation changes in HPV late genes and long control region (LCR) in saliva samples of HPV-HNC patients and HPV-positive controls. Higher methylation levels were detected in HPV late genes (L1 and L2) in both tumour and saliva samples of HPV-HNC patients compared with HPV-positive controls. Moreover, methylation patterns between tumours and corresponding saliva samples were observed to have a strong correlation (Passing-Bablok regression analysis; τ = 0.7483, P < 0.0001). Considering the differences between HNC and controls in methylation levels in late genes, and considering primer amplification efficiencies, 13 CpG sites located at L1 and L2 genes were selected for further evaluation. A total of 18 HNC saliva samples and 10 control saliva samples were assessed for the methylation levels in the selected sites. From the CpG sites evaluated statistically significant differences were identified for CpG sites at L2-CpG 6 (P = 0.0004), L1-CpG 3 (P = 0.0144), L1-CpG 2 (P = 0.0395) and L2-CpG 19 (P = 0.0455). Our pilot data indicate that higher levels of DNA methylation in HPV late genes are indicative of HPV-HNC risk, and it is a potential supplementary biomarker for salivary HPV detection-based HPV-HNC screening.

Performance comparison of two automated digital morphology analyzers for leukocyte differential in patients with malignant hematological diseases: Mindray MC-80 and Sysmex DI-60.

The MC-80 (Mindray, Shenzhen, China), a newly available artificial intelligence (AI)-based digital morphology analyzer, is the focus of this study. We aim to compare the leukocyte differential performance of the Mindray MC-80 with that of the Sysmex DI-60 and the gold standard, manual microscopy. A total of 100 abnormal peripheral blood (PB) smears were compared across the MC-80, DI-60, and manual microscopy. Sensitivity, specificity, predictive value, and efficiency were calculated according to the Clinical and Laboratory Standards Institute (CLSI) EP12-A2 guidelines. Comparisons were made using Bland-Altman analysis and Passing-Bablok regression analysis. Additionally, within-run imprecision was evaluated using five samples, each with varying percentages of mature leukocytes and blasts, in accordance with CLSI EP05-A3 guidelines. The within-run coefficient of variation (%CV) of the MC-80 for most cell classes in the five samples was lower than that of the DI-60. Sensitivities for the MC-80 ranged from 98.2% for nucleated red blood cells (NRBC) to 28.6% for reactive lymphocytes. The DI-60's sensitivities varied between 100% for basophils and reactive lymphocytes, and 11.1% for metamyelocytes. Both analyzers demonstrated high specificity, negative predictive value, and efficiency, with over 90% for most cell classes. However, the DI-60 showed relatively lower specificity for lymphocytes (73.2%) and lower efficiency for blasts and lymphocytes (80.1% and 78.6%, respectively) compared with the MC-80. Bland-Altman analysis indicated that the absolute mean differences (%) ranged from 0.01 to 4.57 in MC-80 versus manual differential and 0.01 to 3.39 in DI-60 versus manual differential. After verification by technicians, both analyzers exhibited a very high correlation (r = 0.90-1.00) with the manual differential results in neutrophils, lymphocytes, and blasts. The Mindray MC-80 demonstrated good performance for leukocyte differential in PB smears, notably exhibiting higher sensitivity for blasts identification than the DI-60.

High concordance of blood glucose measurement in cats between a beta prototype glucometer device and a reference laboratory standard in a clinical setting.

The objective of this study was to evaluate the accuracy of a beta prototype version of a new portable blood glucose meter in feline patients. 60 client-owned cats. In this prospective study, 3-mL blood samples were collected from each cat and analyzed in triplicate using a beta prototype device (AlphaTRAK 3 [AT3]) and by a reference lab standard immediately after collection. Accuracy of the AT3 device was determined in accordance with the International Organization of Standardization (ISO) 15197:2013 criteria, including Bland-Altman plotting and consensus error grid analysis. A Passing-Bablok regression analysis was also performed. 96% of feline measurements fell within the ISO accuracy threshold, and 100% of measurements fell within zones A and B of the consensus error grid, meeting the ISO accuracy requirements. There was no significant bias in the data according to the Bland-Altman analysis. Within the full range of glucose concentrations (20 to 750 mg/dL) the correlation coefficient between the AT3 and the reference lab standard was 0.99. There was no significant constant or proportional bias present in the data. The AT3 device met the ISO requirements and is accurate for measurement of blood glucose concentrations in cats.

Analytical Variability and Agreement of Leukocyte Quantification Methods in Inland Bearded Dragons (Pogona vitticeps)

Abstract Hematology is a common diagnostic assay for evaluation of health in veterinary species. Several manual methods exist to evaluate the leukocyte component of reptile complete blood counts; however, there is no single method that has been proven reliable for all reptiles. To investigate the analytical variability and agreement of commonly used leukocyte quantification methods, blood was collected from ten clinically healthy bearded dragons (Pogona vitticeps) and analyzed in triplicate using Natt-Herricks (NH), eosinophilic leukopet (LO), and estimated white blood cell counts on peripheral blood smears made from fresh whole blood or blood anticoagulated with lithium heparin (LH). To investigate inter-observer variability, blood film white blood cell estimates were generated by both a novice veterinary student and a boarded clinical pathologist and analyzed for agreement. Analytical variability was highest using the LH blood film estimate by a boarded clinical pathologist (21.0%), followed by Natt-Herricks method (student) (20.8%), fresh whole blood film estimate from the clinical pathologist (16.6%), eosinophilic leukopet (student) (8.7%), and blood film estimates using fresh whole blood (6.5%) and LH blood (4.5%) read by the student. Bland Altman plots revealed there was agreement between LO and NH methods and between the two blood film estimate methods, and Passing-Bablok regression analysis revealed constant and proportional error between LO and both estimate methods and between NH and both estimate methods. There was agreement between the veterinary student and clinical pathologist for both blood smear leukocyte estimates. These results highlight the importance of considering which leukocyte quantification method is used when clinically assessing reptile patients.

Commercially available wearable health monitor in dogs is unreliable for tracking energy intake and expenditure.

Assess the accuracy of predicted daily energy requirement (pDER) reported by a triaxial accelerometer and activity monitor for dogs (FitBark 2; FitBark Inc) and determine whether the activity monitor accurately estimates the observed daily energy requirement (oDER). We hypothesized that the activity monitor would accurately estimate oDER in dogs and meet standards established for human devices. 23 dogs between the ages of 1 and 10 years and variable sex, breed, and body weight were enrolled from May 5, 2021, through July 23, 2021. Dogs were weighed before and after the study period to ensure stable body weights. Owners recorded their dogs' daily caloric intake for the entire 28-day study period while the device monitored physical activity and calculated pDER. oDER was defined as the reported caloric intake required to maintain a stable body weight over a 28-day period. pDER and oDER were compared using Bland-Altman graphs, Passing-Bablock analysis, and Lin's Concordance correlation analysis. P ≤ .05 was considered significant. 23 apparently healthy dogs completed the study. There was no significant difference between starting body weights and ending body weights (P= .5). The activity monitor overpredicted 28-day pDER compared to 28-day oDER in the majority (18/23, 78.3%) of dogs. Based on Bland-Altman analysis, Passing-Bablok regression, and Lin's concordance correlation analysis, there was poor agreement between the pDER and oDER. The activity monitors consistently reported inaccurate pDER compared to oDER. Its usability for estimating pDER is of limited clinical and research utility based on the results of this study.

Performance evaluation of PLT-H (hybrid-channel platelet) under various interferences and application studies for platelet transfusion decisions

The hybrid-channel platelet counting method (PLT-H) is a new platelet counting technique proposed by Mindray of China. In this study, we aimed to evaluate the accuracy of this technique in various situations and its reliability in platelet transfusion decision-making. A total of 378 venous blood samples were tested. Using the immunological PLT counting method recommended by the International Council for Standardization in Hematology as the reference method (PLT-IRM), Passing-Bablok regression and Bland-Altman analysis were performed on the PLT-H results. The anti-interference performance of PLT-H under different interference levels was explored using intergroup comparisons, and confusion matrices were analyzed at various transfusion cutoff values. In the absence of interference, there was a strong correlation between PLT-H and PLT-IRM (r = 0.993, 95% CI: 0.990–0.996). Under various interference conditions, the correlation between PLT-H and PLT-IRM was between 0.963 and 0.992, with an average deviation of −14.56 to −2.02. The performance of PLT-H against interference did not change significantly with increasing levels of small RBCs, large PLTs, and RBC fragments (P = .5704, 0.0832, 0.9893). In low-value samples (PLT <100 × 109/L), the coefficient of variation (CV) for PLT-H was less than 7.6%, regardless of the presence or absence of interfering substances. In addition, there was a high agreement between PLT-H and PLT-IRM (ICC = 0.972). Confusion matrice analysis at each medical decision level showed similarity to methods using the fluorescence channel (PLT-O) and superiority to the impedance channel (PLT-I). Compared with PLT-I, PLT-H has higher accuracy in PLT counting, stronger anti-interference ability, better performance in low-value samples at no extra economic cost and can be more useful for platelet transfusion decision-making. PLT-H is a novel method for platelet counting that offers higher accuracy, providing physicians with the ability to make better medical decisions, particularly in cases where values are low, or interference is present. As it does not require additional reagents, it is highly likely to replace PLT-I and become the mainstream method for platelet counting in the future.

Development of a robust TaqMan probe-based one-step multiplex RT-qPCR for simultaneous detection of SARS-CoV-2 and Influenza A/B viruses

BackgroundDuring the coronavirus disease 2019 (COVID-19) pandemic, the simultaneous detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and Influenza A, and Influenza B viruses is essential for rapid differential diagnosis in patients with similar symptoms, especially during “flu season” in the post-pandemic era. So far, several multiplex methods have been approved for the simultaneous detection of SARS-CoV-2, Influenza A, and Influenza B. However, due to the rapid mutation rate of the SARS-CoV-2 genome and the emergence of new variants, existing methods must be improved and updated.MethodsTo identify a highly conserved region in the SARS-CoV-2 N-gene, a genomic survey was performed to increase the sensitivity and specificity of primer and probe sets targeting the SARS-CoV-2 genome. The 95% LLOD (95% lower limits of detection) were calculated by probit analysis. A total of 70 predetermined clinical samples using singleplex RT-qPCR assays, were included. The clinical performance of the multiplex RT-qPCR assay was determined and compared with a commercial multiplex kit. The Cohen’s kappa coefficient, P-value (McNemar’s test), Passing-Bablok regression, and Bland Altman agreement analysis were determined to monitor the agreement of the assays.ResultsThe novel SARS-CoV-2 primer and probe set designed in this assay was able to detect all variants of concern (VOCs) and variants of interest (VOIs) with high analytical and clinical performance. The 95% LLOD for the multiplex RT-qPCR was 20 copies per reaction for the N gene of SARS-CoV-2, 2 copies per reaction for M1 gene of Influenza A and NS1 gene of Influenza B. The diagnostic sensitivity of the multiplex RT-qPCR was 94.4%, 93.7%, and 100% for the detection of SARS-CoV-2, Influenza A, and Influenza B genomes, respectively. Moreover, the specificity was identical (100%) in both assays. According to the agreement analysis results, there was no statistical difference between our multiplex assay and the commercial kit.ConclusionsIn this study, we developed a novel in-house made multiplex RT-qPCR assay, with high sensitivity, specificity, and reliability for the diagnosis of SARS-CoV-2 infection in clinical samples. This is valuable during Influenza seasons when influenza co-circulates with SARS-CoV-2, as it saves costs, time, and thus specific and timely treatment of patients.

Concordance between low density lipoprotein cholesterol concentration measurement by enzymatic method and calculation by Friedewald formula in cardiovascular risk classification

Accurate estimation of low-density lipoprotein cholesterol (LDL-C) is important for cardiovascular risk assessment and guiding cholesterol-lowering therapy. Due to the high cost of β-quantification (Gold standard) and time-consuming, direct measurement of LDL-C is an alternative method. However, unlike the calculation of LDL-C by Friedewald formula, there is an additional cost in terms of reagents for performing a direct LDL-C test. The current study aimed to compare direct LDL-C concentration determination to data calculated by Friedewald formula. 752 lipid profiles of 710 people with LDL-C estimated by direct LDL assay, in the Biochemistry laboratory of university hospital center of Angré, were included in the study. In the same group, LDL-C was calculated using Friedewald formula. Lin’s concordance correlation coefficient (ccc) and Passing-Bablok regression analysis using, MedCal software, were performed to assess the strength of concordance between the 2 methods, and identify any possible bias. The concordance between the two methods was moderate (ρc = 0.9466). Passing-Bablok regression analysis revealed a systematic bias between the two methods. The total error observed (TEobs) between the two methods was higher than allowable total error recommended by the NCEP-ATPIII when LDL-C values was less than 159 mg/dL (4.112 mmol/L). The Friedewald formula resulted in lower LDL-C concentration values. Despite its cost-effectiveness in the estimation of LDL-C, an underestimation of LDL-C levels could result in inaccurate cardiovascular diseases (CVD) risk assessments and potentially significant future societal costs due to inadequate prevention and treatment of CVD.