Passing-Bablok Regression Analysis Research Articles

A Comparative Study of Three Nucleic Acid Integrity Assay Systems.

Background: The measurement of nucleic acid quality, especially the analysis of integrity, is a key step for many downstream experiments in biomedical research and quality control of biomaterials. General gel electrophoresis is a traditional method for nucleic acid integrity analysis. Currently, more electrophoresis techniques are becoming standardized and automated operations with higher precision. In this study, we have evaluated the comparability and bias of the outcomes from three commercial assay systems. Methods: Seventy-two deoxyribonucleic acid (DNA) and 67 ribonucleic acid (RNA) samples were selected for methodological comparison among different systems. The DNA Quality Number (DQN) and RNA Quality Number (RQN) of BIOptic Qsep400, DNA Quality Score (DQS) and RNA Quality Score (RQS) of PerkinElmer Labchip GX Touch HT were separately compared with the DNA Integrity Number (DIN) and RNA Integrity Number (RINe) of the Agilent 4200 TapeStation according to Clinical and Laboratory Standards Institute (CLSI) guideline (EP09-A3). Results: The biases of the mean estimated between DQN and DIN, DQS and DIN both exceeded the acceptance criteria. The Passing-Bablok regression analysis between DQN and DIN, and the Deming regression analysis between DQS and DIN, showed the biases were both within the acceptance criteria, and the bias between DQN and DIN was smaller. For the comparisons of RQN and RINe, RQS and RINe, the regression analyses revealed the biases were both within the acceptance criteria. The bias of the mean estimated between RQS and RINe was outside of the acceptance criteria. Conclusions: There was a good comparability in nucleic acid integrity detection between BIOptic Qsep400 and PerkinElmer Labchip GX Touch HT with the Agilent 4200 TapeStation. However, the bias and linear correlations require more attention between systems.

Partial validation of the Vcheck canine pancreatic lipase assay.

Measurement of canine pancreatic lipase immunoreactivity (cPLI) is used for diagnosing pancreatitis in dogs. Because pancreatitis can be a life-threatening disease with severe complications, an in-house cPLI test would be valuable to obtain rapid test results. The aim of this study was to evaluate a point-of-care cPLI test, Vcheck cPL. Precision, determined according to EP15, and linearity under dilution were determined and judged against preset quality goals. Results from the Vcheck cPL were compared with a previously validated cPLI ELISA, Spec cPL. In a retrospective study, cPLI results from dogs with and without acute pancreatitis, as determined by pancreatic ultrasound examination, were investigated to assess the performance of the assay in a clinical setting. Statistical analysis included the Mann-Whitney test, Chi-square test, and Passing-Bablok regression analysis with a significance level of 0.05. Precision of the assay was acceptable, with intra-, inter-, and total coefficients of variation (CV%) less than 12.1%, 6.4%, and 12.1%, respectively. Results from the linearity study indicated that the method was acceptably linear at lower concentrations but not in the high-concentration range. The method comparison study revealed that Vcheck generally measured higher concentrations compared with Spec cPL, and that the methods should not be used interchangeably. Dogs with acute pancreatitis had significantly higher cPLI concentrations compared with dogs without pancreatitis (P < 0.01), but there was a marked overlap in cPL concentrations between the two groups.

An isotope dilution-liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS)-based candidate reference measurement procedure (RMP) for the quantification of gabapentin in human serum and plasma.

To describe and validate a reference measurement procedure (RMP) for gabapentin, employing quantitative nuclear magnetic resonance (qNMR) spectroscopy to determine the absolute content of the standard materials in combination with isotope dilution-liquid chromatograph-tandem mass spectrometry (ID-LC-MS/MS) to accurately measure serum and plasma concentrations. A sample preparation protocol based on protein precipitation in combination with LC-MS/MS analysis using a C8 column for chromatographic separation was established for the quantification of gabapentin. Assay validation anddetermination of measurement uncertainty were performed according to guidance from the Clinical and Laboratory Standards Institute, the International Conference on Harmonization, and the Guide to the expression of uncertainty in measurement. ID-LC-MS/MS parameters evaluated included selectivity, specificity, matrix effects, precision and accuracy, inter-laboratory equivalence, and uncertainty of measurement. The use of qNMR provided traceability to International System (SI) units. The chromatographic assay was highly selective, allowing baseline separation of gabapentin and the gabapentin-lactam impurity, without observable matrix effects. Variability between injections, preparations, calibrations, and days (intermediate precision) was <2.3%, independent of the matrix, while the coefficient of variation for repeatability was 0.9-2.0% across all concentration levels. The relative mean bias ranged from-0.8-1.0% for serum and plasma samples. Passing-Bablok regression analysis indicated very good inter-laboratory agreement; the slope was 1.00 (95% confidence interval [CI] 0.98 to 1.03) and the intercept was-0.05 (95% CI -0.14 to 0.03). Pearson's correlation coefficient was≥0.996. Expanded measurement uncertainties for single measurements were found to be≤5.0% (k=2). This analytical protocol for gabapentin, utilizing traceable and selective qNMR and ID-LC-MS/MS techniques, allows for the standardization of routine tests and the reliable evaluation of clinical samples.

Assessment of a compounded synthetic adrenocorticotropic hormone product in 17 healthy dogs.

Synthetic adrenocorticotropic hormone or tetracosactide is routinely used in the diagnosis of hypoadrenocorticism and frequently in the diagnosis and treatment of hyperadrenocorticism. There have been repeated shortages of tetracosactide in recent years in Australia. This study investigated the agreement of serum cortisol after a compounded tetracosactide (Bova Aus), compared to commercial tetracosactide (Synacthen®) in healthy dogs. Prospective crossover study using 20 dogs. Ten dogs received 5 μg/kg Synacthen® on day 1 and 5 μg/kg compounded tetracosactide on Day 2. The other 10 dogs received the reverse order. Cortisol concentrations in each dog 1 h after injection were compared for agreement, which was defined as the limits of agreement of the Bland-Altman ratio to be within a range of 0.8-1.25. Passing-Bablok regression analysis examined for constant and proportional biases. Three dogs were excluded with post-stimulation serum cortisol concentrations markedly outside reference interval. For the remaining 17 dogs, Bland-Altman ratio analysis of cortisol concentration (tetracosactide/Synacthen®) at 1 h found virtually no constant bias (mean of ratios 1.01;95% CI 0.97-1.05) and 95% limits of agreement were 0.88 (95% CI 0.78-0.90) and 1.17 (95% CI 1.13-1.25). This met our criteria for agreement between cortisol concentrations. Bias of the Bland-Altman difference was 2.8 nmol/L (95% CI -7.2 to 12.8); 95% limits of agreement -35.2 nmol/L (95% CI -57.0 to -26.1) and 40.8 nmol/L (95% CI 31.7-62.6). Passing-Bablok regression analysis did not identify bias. In healthy dogs, cortisol concentrations were in agreement after compounded tetracosactide compared to commercial tetracosactide, Synacthen®.

Performance analysis of urine formed element analyzer EH-2090 was found to have good accuracy in detecting RBCs and WBCs when compared to manual microscopic.

EH-2090 is Mindray's new-generation fully automatic urine formed element analyzer (hereinafter referred to as EH-2090). Currently, there are no studies on EH-2090, so we evaluated the analytical and clinical performance of this instrument to verify that it can meet daily clinical needs, and used manual microscopy as a reference method. The analytical performance of the EH-2090 was first evaluated for repeatability, linearity, reproducibility, and carryover. We collected urine samples from outpatient and inpatient departments of Peking University Shenzhen Hospital. Uncentrifuged urine was compared with the EH-2090 using the Fuchs-Rosenthal counting method-a quantitative reference method for microscopy-for comparative studies in terms of red blood cell (RBC) and white blood cell (WBC) counting accuracy. Passing-Bablok regression analysis was performed for RBC and WBC counts. Two laboratory technicians performed centrifugation and manual analysis (microscopy) to evaluate its performance at detecting RBCs, WBCs, and casts, sensitivities and specificities were calculated. The EH-2090's between-run reproducibility, within-day reproducibility, between-day reproducibility, and within-laboratory reproducibility for formed components of urine all met the laboratory requirements. There was a good correlation between the counting accuracy of RBCs (r=0.965, P<0.0001) and WBCs (r=0.894, P<0.0001) by the EH-2090 and the Fuchs-Rosenthal method. The positive coincidence rates of RBC and manual microscopy were 86.08% and 92.41%, respectively, and the negative coincidence rates were 88.39% and 85.81%, respectively. The positive coincidence rates before and after the WBC review were 89.33% and 92.00%, respectively, whereas the negative ones were 77.64% and 83.23%, respectively. The positive coincidence rates before and after cast review were 77.78% and 82.05%, respectively, and the negative ones were 97.09% and 93.60%, respectively. The EH-2090 has good analytical and clinical performance. Its RBC and WBC counting accuracy correlates well with the quantitative reference method of microscopy.

PS-C21-10: A LC-MS/MS-EQUIVALENT VALUE OF ALDOSTERONE MEASUREMENT BY A NEW CHEMILUMINESCENT ENZYME IMMUNOASSAY USING A TWO-STEP SANDWICH METHOD

Primary aldosteronism (PA) is the most frequent cause of secondary hypertension. Patients with PA have an increased risk of cardiovascular events, such as cerebral infarction, myocardial infarction, and chronic kidney disease, compared to those with essential hypertension, and early diagnosis makes PA a treatable disease. In clinical practice, accurate measurement of plasma aldosterone concentration (PAC) is crucial because entire diagnostic tests critically depend on aldosterone concentrations. Recently, we developed a new chemiluminescent enzyme immunoassay (CLEIA) using a two step sandwich method to measure aldosterone concentrations. We measured PAC in blood samples from patients using a radioimmunoassay (RIA) and the CLEIA (with current and newly improved reagents) as well as liquid chromatography tandem mass spectrometry (LC MS/MS). Based on the results of the Passing Bablok regression analysis, the aldosterone levels measured using CLEIA with the new reagents and those measured by LC MS/MS were found to be significantly correlated. However, aldosterone levels were lower with the improved CLEIA method than with RIA and CLEIA using the current reagent. Since April 2021, the plasma aldosterone concentration has been measured by CLEIA in Japan. As a provisional response due to changes of the measurement method, the Japan Endocrine Society Clinical Practice Guideline for the Diagnosis and Management of Primary Aldosteronism 2021 was announced. This time, we will report on the new measuring method.

Comparison of measured LDL cholesterol with calculated LDL-cholesterol using the Friedewald and Martin-Hopkins formulae in diabetic adults at Charlotte Maxeke Johannesburg Academic Hospital/NHLS Laboratory.

The National Cholesterol Education Programme Adult Treatment Panel III (NCEP ATP III) and the European Society of Cardiology recommend using low-density lipoprotein cholesterol (LDL-C) as a treatment target for cholesterol lowering therapy. The Friedewald formula underestimates LDL-C in non-fasted and hypertriglyceridemia patients. This study aimed to compare measured LDL-C to calculated LDL-C in diabetic patients using the Friedewald and Martin-Hopkins formulae. The data of 1 247 adult diabetes patients were retrospectively evaluated, and included triglycerides (TG), LDL-C, total cholesterol, and high-density lipoprotein cholesterol that were measured on the Roche Cobas® c702. Passing-Bablok regression analysis was used to determine the degree of agreement between measured LDL-C and calculated LDL-C using both formulae. The Bland-Altman plots were used to assess the bias at medical decision limits based on the 2021 European Society of Cardiology (ESC) guidelines on cardiovascular disease prevention in clinical practice. Both formulae showed a good linear relationship against measured LDL-C. However, the Martin-Hopkins formula outperformed the Friedewald formula at LDL-C treatment target <1.4mmol/L. The Friedewald formula and the Martin-Hopkins formula had 14.9% and 10.9% mean positive bias, respectively. At TG-C ≥1.7 mmol/L, the Martin-Hopkins formula had a lower mean positive bias of 4.2% (95% CI 3.0-5.5) compared to the Friedewald formula, which had a mean positive bias of 21.8% (95% CI 19.9-23), which was higher than the NCEP ATP III recommended total allowable limit of 12%. The Martin-Hopkins formula performed better than the Friedewald formula at LDL-C of 1.4 mmol/L and showed the least positive bias in patients with hypertriglyceridemia.

Clinical irrelevance of lower titer thyroglobulin autoantibodies in patients with differentiated thyroid carcinoma.

Thyroglobulin (Tg) is an established tumor marker for differentiated thyroid carcinoma (DTC) patients. However, Tg immunoassays can be subject to Tg autoantibody (TgAb) interference resulting in incorrect Tg values. Therefore, Tg measurement with liquid chromatography-tandem mass spectrometry (LC-MS/MS) could be promising in patients with TgAbs. In this study, we compared Tg IRMA and Tg-LC-MS/MS analytically in the presence of TgAbs. Furthermore, we compared the clinical interpretation of results obtained by both Tg assays in DTC patients with lower TgAbs titers (<10 U/mL) during 131I ablation therapy. Totally 118 DTC patients diagnosed between 2006 and 2014 in a University Medical Center were followed with the Tg-IRMA (Thermo Fischer Scientific) and ARCHITECT anti-Tg (Abbott Laboratories) assays. We re-analyzed their samples with a sensitive Tg-LC-MS/MS method (Labcorp, limit of quantification of 0.02 ng/mL). Passing-Bablok regression analysis was performed on samples obtained during 131I ablation therapy and follow-up. In 304 samples with lower TgAb titers, a good analytical agreement was found between both Tg assays (slope of 1.09 (95% CI: 1.05-1.16)). Fifty-five samples with potentially interfering TgAbs showed higher Tg-LC-MS/MS values than Tg-IRMA (slope of 1.45 (95% CI: 1.12->>100)). In patients(n = 91) with lower TgAb titers at the time of 131I ablation therapy, the Tg assays showed a clinical concordance of 91.2, 87.9, and 98.9%, respectively, using a Tg cut-off value of 1.0, 2.0, and 5.0 ng/mL. In DTC patients with lower titer TgAbs, Tg-IRMA is still a reliable and useful tumor marker. In DTC patients with potentially interfering TgAbs, Tg-IRMA values decreased due to TgAb interference.

Verification of the Bühlmann fPELA turbo faecal elastase assay on the Binding Site Optilite benchtop analyser.

Pancreatic elastase-1 (PE1) can be measured to assess exocrine activity of the pancreas. A semi-automated particle-enhanced, open-channel turbidimetric immunoassay has been introduced by Bühlmann (fPELA turbo, Bühlmann Laboratories AG, Schoenenbuch, Switzerland). Published evaluation data is lacking. We therefore verified performance of the assay on the Binding Site Optilite benchtop analyser and undertook a sample comparison with the DiaSorin PE1 assay on the Liaison. Accuracy, imprecision, lower limit of quantitation (LLoQ) and linearity of the Bühlmann fPELA turbo assay on the Binding Site Optilite analyser was ascertained. Comparison with the DiaSorin Liaison PE1 assay was also undertaken. Difference between assays was evaluated using the Wilcoxon signed-rank test and method comparison was undertaken using Spearman's rank correlation (rs), Bland-Altman and Passing-Bablok regression analyses. The fPELA turbo assay was linear between 5 and 2500μg/g. The LLoQ was 5µg/g. Intra- and inter-assay imprecision was <6%. There was a good agreement (rs = 0.92) and no significant bias (5.8µg/g, P = 0.29) present between the Bühlmann fPELA turbo and DiaSorin PE1 assays. The Bühlmann fPELA turbo assay performs well on the Binding Site Optilite analyser. Faecal elastase results are commutable between with Bühlmann fPELA turbo and DiaSorin Liaison PE1 assays.

Global and regional left ventricular deformation evaluation with feature tracking in transthyretin cardiac amyloidosis. Comparison with echocardiographic findings

Abstract Background Diagnosis of cardiac amyloidosis (CA) is basically based on imaging techniques. Transthoracic echocardiography (TTE) is crucial to raise suspicion of this disease through detection of the classical features. An specific left ventricular (LV) deformation pattern with apical sparing (“cherry on top”) has been described on speckle tracking (ST) TTE. However, there is no data regarding the role of the LV global and regional analysis with the new tool feature tracking (FT) of cardiac magnetic resonance (CMR) in CA. Purpose Our aim is to analyze the concordance of LV deformation between ST-TTE and FT-CMR. Methods Consecutive patients with definitive diagnosis of transthyretin (TTR) CA, based on DPD scintigraphy, and imaging evaluation with TTE and CMR were retrospectively included. LV volumes and ejection were calculated from both TTE and CMR following the ongoing recommendations. Global and segmental longitudinal strain values were obtained from apical 2-, 3- and 4-chambers projections on TTE, while the same parameters were calculated on the same cine views of CMR using a dedicated software of FT analysis. Student t-test was used to compared mean measurements derived from both imaging techniques. Apical index was calculated as the ratio between apical and basal-mid longitudinal values. Moreover, agreement was established using Passing-Bablok regression analysis. Results 27 patients (80 years-old, 88% men) with definitive diagnosis of TTR CA from our tertiary hospital were included. Regarding echocardiographic findings, 80% showed concentric LV hypertrophy with low normal ejection fraction in the majority (52±10%). When longitudinal LV strain parameters were compared (Table 1), no differences were noted in global and apical values whereas basal and mid measurements were higher from CRM resulting in different apical indexes. Although 42% showed a typical “cherry on top” pattern in ST analysis, in only 18% of the FT apical sparing was detected. Consistently, decremental pattern was observed in 60% of TTE and in 20% of CMR. Concordance analysis with Passing-Bablok showed no constant or proportional differences, meaning both techniques were comparable. Conclusions Among patients with TTR CA there were no differences in global longitudinal LV strain analysis between ST-TTE and FT-CMR. Nevertheless, discordance in regional parameters resulted in a less frequent detection of apical sparing in CMR. Funding Acknowledgement Type of funding sources: None.

Comparison of high performance liquid chromatography and turbidimetric inhibition immunoassay methods for measurement of hemoglobin A1c

Aim: Hemoglobin A1c is a valuable parameter for the diagnosis and follow-up of its diabetes mellitus since its biological variation is low, does not require preparation before the test, is not affected by acute stress, and has high preanalytical stability. HbA1c measurement by HPLC has been determined as the reference method by National Glycohemoglobin Standardization Program (NGSP) in USA; after that The International Federation of Clinical Chemistry (IFCC) defined another reference method which could be related with NGSP. In our study, we aim to compare the two NGSP-certified methods of HbA1c, which are high-performance liquid chromatography (HPLC) and turbidimetric inhibition immunoassay (TINIA).&#x0D; Material and Method: HbA1c levels of the patients were measured using two HPLC and one TINIA method in three different hospitals (Lab A, Lab B (Both are HPLC), and Lab C (TINIA), in which Lab A was served as a reference). Because of the lower precision values of LabB, we firstly conducted a method comparison study of 40 volunteers (Group 1). After that, corrective and preventive activities carried out and the precision values in LabB reached the desired range. Following this, another method comparison study consisting of 60 new volunteers (Group 2) was conducted. The statistical flow of this study complied with Clinical Laboratory Standards Institute (CLSI) EP09-A3; Precision studies, Blant-Altman and Passing Bablok regression analysis were performed.&#x0D; Results: The percentage of the mean difference between the two HPLC methods (LabA and LabB) was 3.1%. After corrective and preventive actions had been taken, the mean difference between the two HPLC methods decreased to 2.0%. A decrease in systematic bias was found in our study. Two HPLC methods can be used interchangeably in both Group 1 and Group 2. In Group 1; 95% CI of intercept and slope were found as (-1.41 to -0.30) and (1.03 to 1.22), respectively. In Group 2; 95% CI of intercept and slope were found as (-1.33 to -0.31) and (1.01 to 1.17), respectively. HPLC and TINIA methods could not be used interchangeable without affecting patient results and outcome in both Group 1 and Group 2.&#x0D; Conclusion: Our study concluded that TINIA and HPLC methods could not be used interchangeably without affecting patient results and outcome. Because of the methodology that clinical laboratories are used to, clinicians and clinical biochemists should collaborate on managing diabetes mellitus regarding diagnosis, treatment, and follow-up.

Cell counting chamber vs. Sysmex XN-1000 for determining white blood cell count and differentiation for body fluids

Abstract Objectives Sterile body fluids (BFs) include key information for the diagnosis and monitoring of a variety of diseases. A cornerstone test is the total white blood cell (WBC) count, which comprises the differential of WBC of body fluid analysis. It is important to test automated hematology analyzers that should be verified using patient samples. The aim of this study is to compare both the performance of the Sysmex XN-1000 system’s body fluid module for cell counting and differentiation to the results of a cell counting chamber. Methods This study was performed on 200 routinely laboratory sent BFs. Cell counts and differentiation were determined with both bright-lined Neubauer Cell Counting Chamber and Sysmex XN-1000 system body fluid mode. Results The correlation coefficients of WBC count by two methods indicated very strong correlation (r≥0.90, p&lt;0.0001) for any specimen except pleural fluid. According to Passing-Bablok regression analysis, Sysmex XN-1000 showed acceptable performance according to bias of the slope criteria (&lt;±20%). Conclusions The XN-1000 hematological analyzer’s body fluid mode can rapidly count and identify cells, and it can be used as a simple and rapid screening method for laboratory testing of sterile body fluids, particularly in laboratories with a massive quantity of biological fluids.

Performance Comparison of Dymind DH-76 and Sysmex Xn-1000 Automated Hematology Analyzers

An automatic hematology analyzer is an essential instrument for the modern laboratory. A new hematology analyzer must undergo comparability testing with a currently used hematology analyzer. This study aimed to compare the performance of the Dymind DH-76 and Sysmex XN-1000 hematology analyzers. This study involved 96 EDTA blood samples from patients aged 18 to 85 years old at a hospital in Jakarta. A complete blood count was performed on each blood sample using two above-mentioned analyzers Dymind DH-76 and Sysmex XN-1000. The results from both instruments were compared by using the Pearson correlation test and the Passing-Bablok regression analysis to determine the agreement in performance between the two instruments. Between the Dymind DH-76 and Sysmex XN-1000, there was a high degree of agreement and correlation concerning the investigated parameters with r &gt; 0.900 and p&lt;0.001 for the parameters RBC, HGB, WBC, HCT, MCV, MCH, and neutrophil, monocyte, and eosinophil counts. The MCHC parameter had the values of r=0.797; p=0.0001, while the lymphocytes parameter had r=0.734 and p=0.0001. Only the basophils parameter showed a different result between the two aforementioned analyzers, with r=-0.179 and p=0.102. The majority of complete blood count parameters showed an excellent correlation and a high degree of agreement between the two instruments. The Dymind DH-76 hematology analyzer meets international standards (National Committee for Clinical Laboratory Standards/NCCLS) and can be used for hematological assay in the laboratory.

Serum neurofilament levels in patients with multiple sclerosis: A comparison of SIMOA and high sensitivity ELISA assays and contributing factors to ELISA levels

BackgroundSerum neurofilaments (sNfs), especially the most investigated serum neurofilament light chain (sNfL), are promising biomarkers in multiple sclerosis (MS). However, their clinical utility is still limited, given the availability and costs of accessible analytical methods. The gold standard for the detection of sNfs is represented by the single molecule arrays (SIMOA). Recently, a high sensitivity enzyme-linked immunosorbent assay (hsELISA) has also been introduced. The objective of the study was to compare both assays for the determination of sNfL and neurofilament heavy chain (sNfH) concentrations in a defined MS cohort. The second objective was to identify contributing factors to sNfs concentrations determined by hsELISA. MethodsSerum samples were collected from MS patients attending the MS Centre, University Hospital Ostrava, Czech Republic. The levels of sNfs were detected using SIMOA and hsELISA assays. ResultsThe Spearman's rank correlation coefficient between the sNfL SIMOA and sNfL hsELISA and between the sNfH SIMOA and sNfH hsELISA was moderate rs= 0.543 (p = 0.001) and rs= 0.583 (p = 0.001), respectively. The Passing-Bablok regression analysis demonstrated bias between both methods. Equally significant bias between the methods was confirmed by the Bland-Altman plots. Furthermore, confounding factors affecting the sNfL levels were glomerular filtration rate (eGFR; 95% CI -2.34 to -0.04) and sex (95% CI -2.38 to -0.10). The sNfH levels were affected by age (95% CI 0.01 to 0.07), eGFR (95% CI -2.45 to -0.02), body mass index (BMI; 95% CI -0.31 to -0.05), and blood volume (95% CI 0.69 to 3.35). ConclusionThis analytical study showed significant differences between hsELISA and SIMOA methods, especially for the sNfH concentrations. We identified confounding factors for sNfs levels determined by hsELISA. The sNfs levels were influenced by renal function and sex, whilst sNfH levels were affected by age, BMI, and total blood volume.

Comparison of biochemical and hematologic values obtained via jugular venipuncture and peripheral intravenous catheters in dogs

BackgroundSampling from a peripheral intravenous catheter (PIVC) might be a more efficient and less traumatic collection of blood for serum biochemistry (SB) or CBC than direct venipuncture (DV). Agreement between results of samples obtained by these methods has not been evaluated in dogs.ObjectivesThe primary objectives were to determine whether sampling from PIVC could be used in place of DV for dogs. We hypothesized DV and PIVC samples would have clinically equivalent SB and CBC results.AnimalsSixty‐one client‐owned dogs were included in each study arm.MethodsThis was a partially randomized method‐comparison study. Paired DV and PIVC samples obtained within 1 to 2 minutes after, or approximately 24 hours after, placement of a PIVC in a cephalic vein were evaluated for agreement and bias using percentage difference plots (with a priori application of consensus total allowable error), Bland‐Altman analysis, Passing‐Bablok regression analysis, Wilcoxon signed rank test, and McNemar's test.ResultsThere was statistically and clinically acceptable agreement and no bias between sampling methods for the majority of results. Analytes with the most frequent disagreement were aspartate aminotransferase, total bilirubin, potassium, bicarbonate, and leukocyte differential counts, as well as red blood cell count, hemoglobin, hematocrit, and packed cell volume in the hospitalized PIVC sampling group. Few observed differences would change clinical decision making.Conclusions and Clinical ImportancePIVC sampling can provide generally acceptable SB and CBC results for most dogs, but clinicians should be aware of a few values for which disparate results might occasionally be obtained.

Assessment and influencing factors analysis of bromocresol green colorimetry for serum albumin

To investigate the application of bromocresol green Colorimetry (BCG) method in measuring serum albumin (ALB) and to evaluate its influencing factors in different diseases. This study was a cross-sectional study that included 128 people admitted to the department of nephrology, department of general surgery, department of infectious diseases and other departments of the Third Xiangya Hospital of Central South University in July 2021. They were divided into groups according to disease types, including chronic kidney disease group (47 cases), liver disease group (40 cases), other diseases group (41 cases), serum ALB was detected by BCG method and immunoturbidimetry at the same time, and the results were expressed as ALBBCG and ALBI respectively, each group was subdivided into three subgroups according to ALBI results: relatively high-value subgroup, relatively intermediate-value subgroup and relatively low-value subgroup of albumin. ALBI and ALBBCG were compared in all groups and subgroups. Passing-Bablok regression and Bland-Altman diagram analysis were used to evaluate the application of ALBBCG in each group. Immunoturbidimetry was used as a reference method to evaluate the bias of ALBBCG, and the differences between ALBI and ALBBCG were shown as follows:ΔALB= ALBBCG-ALBI. Pearson correlation analysis and multiple linear regression analysis were used to assess the correlation between ΔALB and ALB autoconcentration (ALBI), α1-globulin, α2-globulin, β1-globulin, β2-globulin, γ-globulin, creatinine (Cr), urea (UN), uric acid (UA), aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin (TBil), direct bilirubin (DBil), and C-reactive protein (CRP) levels.The results showed that ALBBCG were higher than ALBI in the relative low subgroups of total patients group, chronic kidney disease group, liver disease group and other disease groups, and the differences were statistically significant (t value was 8.025, 6.878, 2.628, 4.915, respectively, P<0.05). In the relatively high value subgroup, ALBBCG was lower than ALBI, and the differences were statistically significant in the relative high value subgroup of total patients group, liver disease group and other disease groups (t value was -4.388, -2.927, -3.979, P<0.05). Passing-Bablok regression and Bland-Altman analysis showed that the BCG method had proportional bias. In the chronic kidney disease group, the concentrations of ALBI and Cr had the greatest influence on BCG bias, and the regression model equation was ΔALB=5.437-0.146× AlbI-0.001 ×Cr, R²=0.505. In the liver disease group, the concentrations of ALBI, α1-globulin, β1-globulin had the greatest influence on BCG bias, and the regression model equation was ΔALB=3.652-0.230×ALBI+0.398×α1-globulin+1.171×β1-globulin, R²=0.658. In the other disease group, the concentration of ALBI and α2-globulin had the greatest influence on BCG bias, and the regression equation was ΔALB=5.558-0.225×AlbI-0.281×α2-globulin, R²=0.646. The BCG method has a proportion error, and its bias may lead to unacceptable differences. BCG method is mainly affected by the concentration of ALB itself, and may also be affected by α1-globulin, α 2-globulin, β1-globulin, Cr.

Comparison of a portable blood glucose meter analyzer with a benchtop point-of-care chemistry analyzer for measurement of blood glucose concentration in client-owned ferrets (Mustela putorius furo)

Hypoglycemia is common in pet ferrets (Mustela putorius furo) because of the high prevalence of insulinoma in this species. The objectives of this study were to evaluate agreement of a portable blood glucose meter (PBGM) with a benchtop point-of-care (POC) chemistry analyzer for measurement of blood glucose concentration in ferrets, and to assess the clinical impact of using a PBGM for blood glucose measurement. The benchtop POC analyzer was used as the reference analyzer (modified hexokinase method). Glucose concentration was measured from 82 blood samples from client-owned ferrets with the benchtop POC chemistry analyzer and the PBGM. Agreement and bias between measurements were assessed using the Bland-Altman method and a Passing-Bablok regression analysis. A modified Clarke error grid analysis was modelized to evaluate the clinical effect if the PBGM was used rather than the benchtop POC chemistry analyzer. Glucose values obtained with the PBGM were not in agreement with the benchtop POC chemistry analyzer, and it underestimated blood glucose concentration in many cases. However, variation was unpredictable (mean bias, -3.97 mg/dL; range, -52.2 to 64.8 mg/dL), with wide 95% LOA (-47.3 to 38.5 mg/dL). A Passing-Bablok linear regression analysis had a slope of 1.13 (95% confidence interval: 1.00–1.36), and an intercept of -20.78 (95% confidence interval: -38.92 to -9.90), highlighting presence of a proportional and a constant bias. Important clinical error would have occurred in 1% of cases with the PBGM. Unpredictable variation of glucose results obtained with the PBGM could have an important impact on clinical decision making. Thus, the use of a benchtop POC analyzer using hexokinase method for measurement of blood glucose concentration should be favored in ferrets for rapid onsite result obtention.

The Comparison of the Point-of-Care Serum Procalcitonin Assay Method with the BRAHMS Certified Method

Background and Aims: As a method for the diagnosis and management of sepsis, the serum procalcitonin assay is routinely used, especially in the emergency department (ED) and intensive care units (ICU). Procalcitonin has reasonable diagnostic accuracy for bacteremia in hospitalized patients of all age groups with suspected infection or sepsis. This study aimed to compare the Getein Biotech procalcitonin point of care method with the ADVIA Centaur® BRAHMS serum procalcitonin method.&#x0D; Materials and Methods: Linearity,recovery, accuracy, and imprecision studies were carried out to evaluate the analytical performance. Bland-Altman plots and Passing-Bablok regression analysis were used to compare patient results. The Kappa test assessed the concordance between the results at cut-off levels of 0.5ng/mL and 2.0ng/mL.&#x0D; Results: In the linearity study performed by obtaining serial dilutions from high and low-level serum pools, the regression equations were "y=-0.03(-0.07 to 0.05)+1.01(0.7 to 1.08)x" and "y=0.463(-1.16 to 2.01)+0.912(0.72 to 1.04)x" respectively. There is no deviation from linearity with the Cusum test (p=0.99 and 0.57). Average recovery value:86%. The CV% values of Control Level-1,2 were 3.75% and 4.2%. 0.1-50.0ng/ml range shows deviation from linearity determined by Cusum test (p=0.01). There was no deviation from linearity in the range of 0.1-2.0ng/ml (p=0.42). Kappa values were calculated as 0.864 and 0.800 (p&lt;0.001).&#x0D; Conclusions: Getein1600 Procalcitonin test should be used for triage or screening purposes. However, a high constant error and deviation from linearity detected at high concentrations indicate that this test should not be used to initiate an antibiotic therapy or alter the current therapy course.

Accuracy and Reliability of Whole Blood Bilirubin Measurements Using a Roche Blood Gas Analyzer for Neonatal Hyperbilirubinemia Screening and Risk Stratification.

BackgroundAccurate bilirubin measurements are essential for appropriate management of neonatal hyperbilirubinemia. This study aimed to evaluate the accuracy and reliability of whole blood bilirubin measurements obtained using a Roche blood gas analyzer (Roche TBiL), with total serum bilirubin (TSB) measurements determined by the Ortho VITROS 4600 chemistry system (Ortho TSB) serving as a reference.Materials and MethodsMedical records of hospitalized neonates that underwent simultaneous Roche TBiL and Ortho TSB measurements were reviewed for eligibility selection and data collection. The correlations and differences between two sets of results were determined using Passing–Bablok regression analysis and a Bland–Altman plot, respectively. For eligible newborns, the risk of developing severe hyperbilirubinemia was assessed using the Bhutani nomogram. Weighted kappa analysis was used to evaluate the agreement between risk prediction by the two methods.ResultsWe obtained 618 paired Roche TBiL and Ortho TSB results from 309 neonates. Roche TBiL and Ortho TSB measurements showed a good correlation (r = 0.923; 95% CI: 0.905–0.938). Passing–Bablok regression analysis yielded the following equation: Roche TBiL = 0.794 × Ortho TSB + 1.255 mg/dL, with a slope of 0.794 (95% CI: 0.763–0.825) and intercept of 1.255 (95% CI: 1.042–1.417). The average difference between the two methods was 0.1 ± 1.448 mg/dL. A total of 207 neonates were eligible for evaluation of the agreement between the risk-grading methods. Although kappa analysis showed good agreement between the methods, with a weighted kappa of 0.681 (95% CI: 0.610–0.751) across all populations, the values for approximately half of the neonates at intermediate and high risk of hyperbilirubinemia (33/72) were underestimated by Roche TBiL.ConclusionOur results indicate that Roche TBiL and Ortho TSB measurements in the neonatal population are not consistent. As a point-of-care and trace blood assay, Roche blood gas bilirubin measurements can facilitate primary screening of neonatal hyperbilirubinemia, but it seems to lack accuracy regarding risk stratification, particularly for high-risk newborn individuals.

Searching for the urine osmolality surrogate: an automated machine learning approach.

Automated machine learning (AutoML) tools can help clinical laboratory professionals to develop machine learning models. The objective of this study was to develop a novel formula for the estimation of urine osmolality using an AutoML tool and to determine the efficiency of AutoML tools in a clinical laboratory setting. Three hundred routine urinalysis samples were used for reference osmolality and urine clinical chemistry analysis. The H2O AutoML engine completed the machine learning development steps with minimum human intervention. Four feature groups were created, which include different urinalysis measurements according to the Boruta feature selection algorithm. Method comparison statistics including Spearman's correlation, Passing-Bablok regression analysis were performed, and Bland Altman plots were created to compare model predictions with the reference method. The minimum allowable bias (24.17%) from biological variation data was used as the limit of agreement. The AutoML engine developed a total of 183ML models. Conductivity and specific gravity had the highest variable importance. Models that include conductivity, specific gravity, and other urinalysis parameters had the highest R2 (0.70-0.83), and 70-84% of results were within the limit of agreement. Combining urinary conductivity with other urinalysis parameters using validated machine learning models can yield a promising surrogate. Additionally, AutoML tools facilitate the machine learning development cycle and should be considered for developing ML models in clinical laboratories.