Immunoturbidimetric Assay Research Articles

Abstract 4133257: Circulating Ketone Bodies, Lipoprotein(a) and Incident Cardiovascular Outcomes and Mortality: Insights from The UK Biobank

Background: Lipoprotein(a) [Lp(a)] is an independent risk factor for atherosclerotic cardiovascular disease (ASCVD). Recent epidemiological studies have revealed an association between ketone bodies (KB) and adverse cardiovascular outcomes, offering a unique insight into metabolic health and its impact on mortality risk. Elevated levels of both Lp(a) and KB may synergistically amplify pathological processes, including endothelial dysfunction, inflammation, and oxidative stress, through their involvement in shared pathophysiological pathways, thereby exacerbating disease progression beyond the impact of each biomarker individually. Methods: Utilizing data from the UK Biobank, KB were measured by nuclear magnetic resonance spectroscopy and serum Lp(a) concentrations were measured using an immunoturbidimetric assay. Four groups were created as follows: Group 1: Lp(a)<125 nmol/L and Total KB<75 th percentile (<94 μmol/L); Group 2: Lp(a)≥125 nmol/L and Total KB<75 th percentile; Group 3: Lp(a)<125 nmol/L and Total KB≥75 th percentile; and Group 4: Lp(a)≥125 nmol/L and Total KB≥75th percentile. Multivariable-adjusted Cox proportional hazard models were used to examine the association of Lp(a) and total KB with incident cardiovascular outcomes and mortality. Results: A total of 72,704 UK Biobank participants (mean age 56 y, SD=8, 55% women) without prevalent CVD or HF with a median follow up of 13.4 years were included. In the fully adjusted model, compared with those in the reference group (Group 1), participants in Group 2, Group 3, and Group 4 demonstrated a 14%, 17%, and 38%, increased risk of incident ASCVD events, respectively (p<0.01 for all). However, those with Lp(a) ≥ 125 nmol/L and total KB < 75th percentile demonstrated no increased risk of HF, all-cause mortality, stroke, or CVD mortality. Participants with elevated levels of both Lp(a) and KB had significantly increased risk of all outcomes (Table). There was no evidence for a statistically significant interaction between Lp(a) and KB on any outcome. Conclusion: Consistent with prior literature, Lp(a) was associated with atherosclerotic outcomes. However, elevated KB was associated with all outcomes, irrespective of Lp(a) levels.

Temporal variability of Lp(a) in clinically stable patients: Implications for cardiovascular risk assessment

ObjectivesLipoprotein(a) [Lp(a)] is a significant risk factor for cardiovascular disease, yet it is often overlooked in routine clinical assessments. As a primarily genetically determined risk factor, the traditional recommendation is to assess its level once in a lifetime, as the variability of Lp(a) over time is considered to be minimal. This study aims to evaluate the potential variability of Lp(a) in clinically stable patients and investigate factors contributing to the lack of stable levels. MethodsA retrospective analysis was conducted on a sample of adult patients attending a lipid clinic. Participants with at least two Lp(a) measurements taken with a minimum interval of four months were included. Lp(a) measurements were performed using the immunoturbidimetric assay. Variability in Lp(a) values was calculated as a percentage change from baseline, with participants exceeding a 25% change classified as having hypervariable Lp(a) levels. Additional clinical and biochemical variables were assessed. Results61 participants with 171 Lp(a) determinations were included. Thirty-four percent exhibited a variability of 25% or higher (hypervariable). Men showed slightly greater variability than women. Changes in Lp(a) categories were observed among hypervariable patients, with some participants experiencing an increase while others showed a decrease. Menopause was present in all the women with hypervariable levels. ConclusionOur study suggests reconsidering the reliance on a single Lp(a) measurement for assessing cardiovascular risk. Repeat measurements, particularly in borderline cases, may be beneficial.

Lipoprotein(a) levels in acute myocardial infarction patients and their associations with prior events and coronary artery disease severity: a real-world cohort study

Abstract Introduction Circulating lipoprotein(a) [Lp(a)] has been associated with the risk of atherosclerotic coronary artery disease (CAD) and is an emergent therapeutic target. The objective of this study is to explore the association between serum levels of Lp(a) and previous myocardial infarction (MI) and/or coronary revascularization and the extension of obstructive CAD in patients with acute MI undergoing coronary angiography. Methods All consecutive patients with MI who underwent coronary angiography and Lp(a) measurement between May and November 2023 were included. Patient data were either registered prospectively or completed retrospectively using electronic health records. Lp(a) was measured using the Immunoturbidimetric Assay method with reaction intensification by particles, employing the World Health Organization/International Federation of Clinical Chemistry and Laboratory Medicine (WHO/IFCC) International Reference Reagent (SRM2B), on the "Roche Cobas C702" chemistry analyzer. The number of major coronary arteries (left main, left anterior descending, left circumflex and right coronary arteries) with stenosis >50% on the coronary angiography were registered. In the primary analysis we explored the association between Lp(a) levels using tertiles and previous occurrence of MI/revascularization, as well as the extension of obstructive CAD. In the secondary analysis we compared Lp(a) levels in patients with and without previous MI/revascularization and patients with 3-4 major vessels CAD vs. 0-2 vessels. Results A total of 116 patients were enrolled, with a mean age of 62±13 years, 79% males, 29% with known coronary artery disease, 71% with dyslipidemia, 24% with diabetes, 65% with hypertension, and 58% were either active or former smokers. The median Lp(a) level was 72 (20-183) nmol/L. In the primary analysis (table 1), the number of previous MI/revascularizations was significantly higher in the third tertile of Lp(a) (T3) versus T1 (p=0.044). No significant differences were found for the remaining analyses. In the secondary analysis (figure 1) the level of Lp(a) was significantly higher in patients with 3-4 vessel CAD vs. 0-2 vessel (158.4±145.2 nmol/L vs. 103.16±104.6 p=0.044). Conclusion In this small real-world cohort population with acute MI, the number of previous MI or coronary revascularization was higher in patients with increased levels of Lp(a) and this marker of atherosclerotic disease was greater in patients with more extensive CAD.

Relationship between lipoprotein(a) and endogenous fibrinolytic status in patients with STEMI

Abstract Background The risk of myocardial infarction is at least doubled in individuals with lipoprotein(a) (Lp[a]) levels >90th percentile.[1] Lp(a) may exert pro-thrombotic effects by impairing fibrinolysis. Lp(a) has a high degree of homology to plasminogen and can competitively inhibit tissue plasminogen activator (tPA)-mediated plasminogen activation and tPA-mediated clot lysis.[2] Furthermore, Lp(a) stimulates the activity of plasminogen activator inhibitor-1, the major inhibitor of the fibrinolytic system. In patients with ST-segment elevation myocardial infarction (STEMI), impaired endogenous fibrinolysis is a strong, independent risk factor for recurrent cardiovascular events,[3] but the drivers of this are not fully understood. Whether impaired endogenous fibrinolysis is related to increased Lp(a) levels in patients with STEMI, is not known. Purpose We aimed to assess the relationship between Lp(a) and endogenous fibrinolysis in patients with STEMI. Methods In a prospective, observational study, venous blood samples were drawn from patients presenting with STEMI immediately before revascularisation, after dual antiplatelet therapy but before heparin administration. Endogenous fibrinolysis was measured immediately in non-anticoagulated whole blood using the point-of-care Global Thrombosis Test, which measures the time for occlusive thrombus formation under high shear (occlusion time) and the time for spontaneous lysis of the thrombus (lysis time).[3] Assessment of Lp(a) levels, measured by particle enhanced immunoturbidimetric assay, was performed with paired plasma samples, standardized against the International Federation of Clinical Chemistry reference material SRM2B for nmol/L. Lp(a) >32 nmol/L is associated with increased risk of ischaemic heart disease. Results A total of 80 patients were included (age 64±14y, 25% females and 86% Caucasian). There was a positive correlation between Lp(a) level and lysis time (r = 0.330, P = 0.003) (Figure 1). Lysis time was significantly longer in patients with Lp(a) >32 nmol/L (2782 [1626-3683] vs. 1725 [1259-2955] s, P = 0.044). Using a cut-point of lysis time ≥2500 s previously associated with a significantly increased cardiovascular risk in patients with STEMI, we showed that Lp(a) was significantly higher in patients with lysis time ≥2500 s (40 (22-111) vs. 18 (7-73) nmol/L, P = 0.045). Table 1 shows the relationship between clinical characteristics and Lp(a) and lysis time. Lp(a) level was higher in non-Caucasian patients. There was no correlation between Lp(a) and occlusion time (r = 0.156, P = 0.168). Conclusion In patients with STEMI, longer endogenous fibrinolysis time is related to higher Lp(a) level. Raised Lp(a) levels may, in part, contribute to impaired endogenous fibrinolysis. Future studies are required to assess whether reduction in Lp(a) with novel therapies currently in phase 3 trials can favourably modulate fibrinolysis and improve clinical outcomes.Figure 1

5180 Atypical Presentation of Type 2 Diabetes Mellitus in a 72Year Old Caucasian Male with Hemoglobin J-Baltimore Variant: A Case Report

Abstract Disclosure: C. Muojieje: None. M. Luzuriaga: None. Objective: This case report discusses the unusual manifestation of Type 2 Diabetes Mellitus (T2DM) in a 72-year-old Caucasian male possessing a rare Hemoglobin variant, Hemoglobin J-Baltimore. It emphasizes the importance of recognizing how hemoglobin variants can impact HbA1c measurements. Alternative markers, such as fructosamine and HbA1c measurement using turbidimetric inhibition immunoassay (TINIA), are discussed as potential tools for a more precise assessment of glycemic control. Furthermore, it accentuates the effectiveness of tailored treatment strategies in such cases. Methods: A 72-year-old Caucasian male with a history of T2DM was referred to an endocrinology clinic due to substantial discordance between the blood glucose (BG) values when self-monitoring and HbA1c. The patient was diagnosed with T2DM a decade ago due to fasting hyperglycemia. His HbA1c levels had remained within normal range. He exhibited signs of diabetic nephropathy with moderately increased albuminuria. He was never prescribed an oral hypoglycemic agent. He reported polyuria, weight loss, and fatigue, prompting him to monitor his BG at home twice daily, revealing readings > 200 mg/dl. HbA1c measurement using high-performance liquid chromatography (HPLC) was 4.8%. His fasting plasma glucose was 190 mg/dl, and fructosamine levels were 292 umol/L (205 - 285 umol/L). An HbA1c level via TINIA was 6.4%. Hemoglobin electrophoresis unveiled the presence of Hemoglobin J-Baltimore. We started metformin, resulting in an improvement in HbA1c from 6.4% to 5.8%. Fructosamine levels improved from 292 umol/L to 210 umol/L. Fasting blood glucose remained > 150 mg/dl. Dulaglutide was introduced. Follow-up analysis showed an improvement in FBS to < 120 mg/dl. HbA1c remained unchanged at 5.9%. Conclusion: The significance of hemoglobin variants, exemplified by Hemoglobin J-Baltimore, cannot be overstated in the context of patients with T2DM, especially within populations where these variants are uncommon. This case underscores the need for a nuanced approach to glycemic control assessment in such individuals. The utilization of alternative markers, such as HbA1c values obtained through TINIA, emerges as a valuable strategy. The role of continuous glucose monitoring (CGM) is crucial, providing real-time and comprehensive data, which enhances the quality of care and contributes to more tailored and effective treatment strategies. Presentation: 6/1/2024

A-216 Prevalence and status of Lipoprotein(a) in the Korean population visiting local clinics and hospitals

Abstract Background Lipoprotein a (Lp(a)) is a risk factor for cardiovascular disease (CVD) and has pro-atherogenic and pro-inflammatory effects. According to the Justification for the Use of Statins in Prevention: an Intervention Trial Evaluating Rosuvastatin (JUPITER) study, a sub-analysis was published showing that the risk of residual CVD after sufficiently lowering low-density lipoprotein cholesterol can be explained by Lp(a) concentration. The purpose of this study is to determine the prevalence of elevated Lp(a) and to analyze the characteristics of Lp(a) results by age, gender, and region in the Korean population visiting local clinics and hospitals. Methods We retrospectively reviewed Lp(a) test results from the Korean population who visited 117 local clinics and hospitals nationwide between February 2023 and January 2024. Serum levels of Lp(a) were measured by immunoturbidimetric assay. Lp(a) was analyzed to three age groups (<20, 20-59, ≥60 years) according to Lp(a) values (<30 or ≥30 mg/dl). One hundred seventeen local clinics and hospitals across the country were reclassified into 7 regions. Results A total of 15,523 patients (7,702 males and 7,821 females), aged 12-104 years, were included. The median (interquartile range, IQR) age of the population was 59 (49-69) years; the median (IQR) Lp(a) concentration was 9.7 (4.2-21.6) mg/dl. The prevalence of elevated Lp(a) levels (≥30 mg/dl) in this study was 16.7% (13.9% for males, 19.5% for females, p <0.001). Prevalence of elevated Lp(a) levels by age groups were as follows: <20 (8.9%, 5/56), 20-59 (13.9%, 1,071/7,724), ≥60 years (19.6%, 1,516/7,743). The correlation coefficient r between Lp(a) and age was 0.139 (p <0.001). No significant relationship was found between Lp(a) and region. Among 15,523 patients, the number of patients with Lp (a) level ≥100 mg/dl was 174 (n=70 for males, n=104 for females, p=0.128), and median (IQR) Lp(a) concentration was 115.1 (106.8-131.6) mg/dl. Of them, four patients showed extremely high Lp(a) levels (>180 mg/dL). Conclusions The prevalence of elevated Lp(a) in our population visiting local clinics and hospitals nationwide was 14.4% and differed by gender and age group. For successful management and establishment of the policy of CVD, it is important to identify the prevalence of elevated Lp(a). Future study is needed including the clinical information to confirm the present findings.

A-309 Multicenter Performance Evaluation of the ProNephro AKITM Assay and Sample Stability in Pediatric Patients

Abstract Background Acute Kidney Injury (AKI), defined by increased serum creatinine or decreased urine volume, is highly prevalent in critically ill pediatric patients. Those who develop AKI experience worsened outcomes, raising the need for accurate and early biomarkers for AKI. Relying in serum creatinine for AKI diagnosis is unreliable due to its diagnostic inaccuracy and delayed rise in the AKI pathophysiology. Neutrophil Gelatinase-Associated Lipocalin (NGAL) is a novel and widely studied biomarker for early identification of AKI. During pathological progression, NGAL is elevated in blood and urine within two hours of the insult, making it useful for early diagnosis and management of kidney injury in critically ill children. This study aims at evaluating the performance characteristics of a quantitative test for NGAL in urine intended for use in critically ill pediatric patients, and investigating the stability of NGAL in pediatric urine. Methods The ProNephroAKITM is a particle-enhanced turbidimetric immunoassay on the Roche cobas® c501 analyzer to measure NGAL quantitatively in urine in pediatric patients 3 months to 21 years of age. These studies were approved by the respective institutional review boards. The limits of blank (LOB), detection (LOQ) and quantitation (LOQ) were determined following CLSI EP17A2. Linearity was assessed across the measurement range (MR) of 50-3000 ng/mL. The assay repeatability, between-run, between-day and total imprecision were determined in pediatric urine samples (n=9, covering the MR) and controls (n=2) following CLSI EP5-03 guidelines. Likewise, multisite reproducibility was evaluated in pediatric urine (n=7, covering the MR) and controls (n=2) in 3 laboratories and alternating operators. The assay specificity was assessed in the presence of several endogenous and exogeneous substances (e.g. drugs, contrast agents), potential related cross-reactant molecules, and several pH-values. The stability of NGAL in urine was evaluated using freshly collected pediatric urine samples covering the MR from 16 consented patients after storage at ambient (15-30°C), refrigerated (2-8°C), and frozen temperatures (≤-70°C), and following 3 freeze/thaw cycles. Results The ProNephroAKITM is linear across the MR of 50-3000 ng/mL. The LOB, LOD and LOQ were 9, 14 and 18 ng/mL, respectively. The coefficients of variation (CVs) for repeatability, between-run, between-day and total precision were ≤5.0%, ≤3.1%, ≤1.7% and ≤4.9%, respectively in urine and control samples. The reproducibility across 3 independent laboratories was ≤6.6%. The recovery of NGAL was not significantly affected by endogenous substances, contrast agents, pH (3.3-10.3), and common and special pharmaceutical compounds (exception: very high Cefepime concentrations may decrease NGAL), and potential cross-reactants. Freshly collected urine samples spanning concentrations from 71-2,373 ng/mL were stable (±10% recovery) for 2 days at ambient, 4 days refrigerated and 13 months frozen, and after 3 freeze/thaw cycles. Conclusions We report the performance characteristics of the ProNephroAKITM assay, including excellent precision and adequate reproducibility across 3 laboratories, sensitivity, specificity, and urine sample stability. The test was determined to meet the analytical performance required for clinical use in critically ill pediatric patients at risk of developing or having persistent AKI.

B-341 Comparative Study of Free Light Chains in the Framework of the Project Prevalence of Monoclonal Gammopathies in Adult Uruguayan Population

Abstract Background Within the framework of a study to evaluate the Prevalence of Monoclonal Gammopathies in the Adult population of Uruguay through detection monoclonal bands by capillary electrophoresis and free light chains in serum, the aim is evaluating the comparison of quantification of FLC (Free Light Chains) in this group of patients with 2 assays: Freelite Biding Site® versus Sebia® FLC Elisa. Methods Study period: September 2021 to November 2022. Prospective, single-cohort, descriptive study. Approved by the Hospital de Clinicas Ethics committee, Montevideo, Uruguay.A total of 3905 patients were included (≥40 years, without previously known plasma cell disorder).Serum samples were collected from three health centers, and processed in Clinical Chemistry Laboratory at Hospital de Clinicas, following an algorithm designed to perform electrophoretic proteinogram (by capillary electrophoresis); suspicious samples with monoclonal bands were confirmed by immunotyping, and in some cases by immunofixation (difficult interpretation), and quantification FLC by 2 different assays (Sebia FLC: manual sandwich ELISA technique- BIO-TEK wash/reader; Freelite The Binding Site immunoturbidimetric assay : Spa Plus and Optilite instruments. Comparative analysis of FLC is a transversal and descriptive study.For statistical analysis: Spearman test, Passing and Bablok and Bland-Altman plot. Results κFLC, λFLC and ratio κ/ λ were measured in 93 of the 104 positive serum samples for Monoclonal Gammopathies (new diagnoses, prevalence 2.7%), using two groups Sebia FLC and Spa Plus Freelite, and Sebia FLC and Optilite Freelite. During the project, the Spa Plus (n=48) FLC was replaced with Optilite (n=45), since the comparative group was not analytically homogeneous, so the comparison was carried out in two groups. Spearman rank correlation coefficients between first group (N:48) for κFLC, λFLC and ratio κ/ λ were r=0.596, 0,549, 0.709, respectively (p<0.0001); for the second group (N:45) Spearman rank correlation coefficients were r=0.778, 0.714, 0.878, respectively (p<0.0001). The first group showed good Spearman rank correlation for ratio, although less better correlation for kappa and lambda isolated. Bland Altman showed high media differences in assays for values for Sebia. For the second group, there was a better Spearman Correlation for ratio and in kappa and lambda isolated too. Bland-Altman plot revealed, in the second group analysis, that Freelite provides higher values than Sebia in Kappa and ratio, but not in Lambda. Passing Bablock showed differences systematic and proportional in different group of comparatives. Conclusions There is a good agreement; despite this, within high FLC concentrations, there are particularly significant differences between both assays, in both groups. We found in same cases FLC quantifications with Freelite ratios lower than those reported by the Elisa Sebia assay, which in these patients could change the diagnosis and therefore the opportunity for treatment or the time between follow-ups. In other cases, greater amount of ratio FLC assayed by Freelite, which may represent loss of linearity in subsequent dilutions. Falsely high results may occur due to polymerization of light chains.Our results suggest that Sebia FLC is a valid assay alternative, but needs more studies to demonstrate these findings; the prospective follow up of this group promises more.

A-215 Feasibility of a unique homogenous assay for lipoprotein(a) particle number without bias from apo(a) size isoforms

Abstract Background Lipoprotein(a) [Lp(a)] is an LDL-like particle with apolipoprotein(a) [apo(a)] covalently attached to apolipoprotein B. Elevated Lp(a) is associated with increased risk of atherosclerotic heart disease. The structural homology of Lp(a) and plasminogen and the variable number of apo(a) kringle 4 type 2 subunits (k4t2) between individuals, up to 51 repeats and a variable MW of 300-800 kDa, presents an analytical challenge. `Selection of calibrators of specific isoform size does not fix the problem, despite manufacturer’s claims to the contrary. Methods We have developed goat antisera to human apo(a)-specific peptides and a prototype immunoturbidimetric assay for Lp(a). We selected and synthesized 10 peptide sequences (15-30 aa each) distinct from the sequences found in k4t2 regions and plasminogen. Peptides were prepared attached to KLH (GenScript) and combined to immunize goats following a standard protocol including monthly boosters (Nittobo). Next, we assessed various sample volumes, reagent formulations and antisera dilutions to establish parameters on the Randox Imola analyzer. Cross-reactivity with recombinant k4t2 (40 mg/dL) and plasminogen (200 mg/dL, Athens Research) was assessed by comparison to the LOD (using delipidated plasma blank and low concentration samples). Results Titers to human Lp(a)) were positive to 1:6400 dilution of antisera, showing exceptional reactivity. Working formulation/parameters were 10 µL sample, 100 µL PBS, pH 7.4/PEG6000/detergent and 95 µL R2 (antisera). Sample/R1 was incubated for 5-minutes before addition of R2; reaction was monitored at 340 nm/37°C. LOD and linearity were also assessed. No cross-reactivity with k4t2 or plasminogen up to the concentrations tested was observed. Linearity to 330 nmol/L and LOD of 18 nmol/L were found. Conclusions The use of this antisera/assay eliminates the bias associated with apo(a) size polymorphisms and allows for the accurate measurement of Lp(a) particle number. More work is needed to optimize assay parameters and formulation and comprehensively validate assay performance.

External Validation of a Limited Sampling Strategy for the Estimation of Mycophenolic Acid Exposure Between Different Assay Methods: PETINIA and HPLC Methods.

A limited sampling strategy (LSS) for estimating the area under the plasma concentration-time curve (AUC0-12) of the immunosuppressant mycophenolic acid (MPA) is used for therapeutic drug monitoring (TDM) in clinical practice. Our study delves into the applicability of the MPA AUC0-12 LSS, originally developed using particle-enhanced turbidimetric inhibition immunoassay (PETINIA) measurements, to those obtained via high-performance liquid chromatography with ultraviolet detection (HPLC-UV). We developed an LSS for estimating MPA AUC0-12 based on PETINIA measurements in 32 adult kidney transplant patients who were receiving mycophenolate mofetil. Validation of this strategy was conducted in an additional 14 adult kidney transplant patients (validation sets) through measurements obtained by both PETINIA and HPLC-UV. Predictive performance was assessed using mean absolute error (MAE), root mean squared error (RMSE), and "good guess" defined as predicted AUC within observed AUC±15%. The three time point equation (0, 2, and 6h) emerged as optimal for estimating MPA AUC0-12, balancing predictive performance and usefulness in clinical settings. In validation sets, the coefficient of determination for observed versus predicted AUC0-12 was consistent between PETINIA (0.978) and HPLC-UV (0.958) measurements. Comparable MAE, RMSE, and "good guess" outcomes were observed for PETINIA (6.4%, 8.1%, and 85.7%, respectively) and HPLC-UV (7.6%, 9.4%, and 85.7%, respectively) measurements. Our findings support the application of the MPA AUC0-12 LSS, originally developed using PETINIA measurements, to those obtained via HPLC-UV.

Clinical performance of a particle enhanced turbidimetric immunoassay (PETIA) for detecting fecal calprotectin

Particle-enhanced turbidimetric immunoassay (PETIA) is a new measurement procedure for detecting fecal calprotectin (FC). We aimed to investigate the accuracy and clinical performance of PETIA for FC. We assessed the accuracy of PETIA for FC measurements through concordance analysis, Passing-Bablok regression and Bland-Altman analysis, using enzyme-linked immunosorbent assay (ELISA) as the reference. To evaluate the clinical performance of PETIA, the FC levels of individuals with significant and non-significant bowel diseases were compared. The receiver operating characteristic (ROC) analysis was performed to determine the appropriate cut-off value of FC detected by PETIA for discriminating subjects with significant and non-significant colorectal lesions. Of the 413 cases analyzed, 340 (82.3%) were concordant between PETIA and ELISA. No significant discordance was observed. There was a good agreement (y = −7.710+0.957x) between PETIA and ELISA for detecting FC. The FC level detected by PETIA in patients with significant bowel diseases (159.1 [31.3, 821.0] µg/g) was significantly higher than that of subjects with non-significant bowel diseases (10.3 [4.2, 38.5] µg/g) (p < 0.001). The AUC of FC for identifying significant bowel diseases detected by PETIA was 0.82 (p < 0.001). With a cut-off value of 77.6µg/g, the specificity and positive predictive value were 92.2% and 97.1%, respectively. The PETIA for FC measurement showed good clinical performance for detecting bowel diseases.

Duodenal and colonic mucosal S100A8/A9 (calprotectin) expression is increased and correlates with the severity of select histologic lesions in dogs with chronic inflammatory enteropathy

BackgroundCalprotectin, a damage-associated molecular pattern protein of the S100/calgranulin family, is a potential marker of gastrointestinal inflammation in dogs and mainly originates from activated macrophages and granulocytes. Increased calprotectin concentrations are reported in feces and serum samples from dogs with chronic inflammatory enteropathy (CIE), but mucosal calprotectin expression has not been extensively investigated in canine CIE. Thus, we aimed to evaluate gastrointestinal mucosal concentrations of calprotectin in 62 dogs (44 dogs with CIE compared to 18 healthy Beagles) using a particle-enhanced turbidimetric immunoassay method. Additionally, we assessed the relationship of gastric, duodenal, jejunal, ileal, and colonic mucosal calprotectin levels with the clinical disease severity (canine clinical inflammatory bowel disease activity index, CIBDAI), histopathologic findings, clinical outcome, and serum albumin concentrations to further evaluate the potential of calprotectin as a biomarker for CIE.ResultsMucosal calprotectin concentrations in dogs with CIE were significantly higher in the duodenum (median: 276.2 μg/g) and colon (median: 298.2 μg/g) compared to healthy controls (median: 94.3 μg/g, P = 0.0039; and median: 112.0 μg/g, P = 0.0061). Similar numerical differences in the ileum and cecum were not statistically significant, and mucosal calprotectin concentrations correlated significantly among the different gastrointestinal segments. Histologic lesion severity was linked to mucosal calprotectin concentrations for inflammatory and structural histology criteria in the duodenum and colon (all P < 0.05). Higher mucosal calprotectin levels in the duodenum and across all segments correlated with lower serum albumin concentrations (both P < 0.05); duodenal mucosal calprotectin concentrations were more than sixfold higher in hypoalbuminemic dogs (median: 1441 µg/g, n = 4) than normoalbuminemic dogs (median: 227 µg/g, n = 40). There was no significant association of mucosal calprotectin levels with CIBDAI scores or individual clinical outcomes.ConclusionsThese results show that duodenal and colonic mucosal calprotectin concentrations are increased in dogs with CIE, providing further supporting evidence for the diagnostic potential of fecal calprotectin (presumably reflecting mucosal) concentrations and in dogs with CIE. Further longitudinal research is needed to assess changes in mucosal calprotectin concentrations with clinical response to treatment vs. mucosal disease remission and to determine the clinical utility of fecal calprotectin concentrations to diagnose and monitor dogs with CIE in clinical practice.

Comparison of polyclonal and monoclonal antibody assays for serum amyloid A in cats: a study based on an automated turbidimetric immunoassay in a primary care veterinary hospital.

Comparing the utility of the anti-human serum amyloid A (SAA)-specific monoclonal and polyclonal antibodies assays (LZ-SAA) with the pure monoclonal anti-human antibody assays (VET-SAA) during clinical practice in primary care hospital populations by measuring SAA measurement in healthy and diseased domestic cats. 52 healthy and 185 diseased client-owned cats. SAA concentration was measured using different LZ-SAA and VET-SAA measurements for healthy and various diseased cats. Sensitivity, specificity, and accuracy were calculated for each disease. VET-SAA has higher sensitivity than LZ-SAA for the most common diseases presenting to primary care veterinary hospitals, including chronic kidney disease, tumors, and gingivostomatitis. Our results reveal the capability of detecting low SAA concentrations in healthy and diseased cats using VET-SAA in contrast to LZ-SAA, which found elevations of SAA concentrations only in diseased cats. Our findings indicate that switching to the new VET-SAA instead of the conventional LZ-SAA will likely enhance the diagnostic performance in primary care veterinary hospitals.

Impact of Bacterial Etiology on Procalcitonin, C-reactive Protein and Hematological Parameters: Evaluating Mean Platelet Volume for Differentiating Gram-Negative and Gram-Positive Bacteria in Odontogenic Versus Non-odontogenic Head and Neck Abscesses.

Introduction Head and neck abscesses, which can originate from odontogenic or non-odontogenic sources, pose significant diagnostic challenges due to their diverse bacterial etiologies. This study aims to investigate the impact of bacterial etiology on procalcitonin (PCT), C-reactive protein (CRP), and various hematological parameters, and to assess the diagnostic performance of mean platelet volume (MPV) in differentiating between Gram-negativebacteria (GNB) and Gram-positive bacteria (GPB) in adults with odontogenic and non-odontogenic head and neck abscesses. Materials and methods Our retrospective analysis of a prospective study comprised 80 patients: 50 individuals (56% men, average age 41.6±18.18 years) with odontogenic and 30 patients (66.7% men, average age 44.53±15.49 years) with non-odontogenic head and neck abscesses during the period from July 2021 to June 2022. White blood cell count (WBC); neutrophil (Neu) and lymphocyte (Ly) count; MPV, and platelet count (PLT) were derived from the results of complete blood count. MPV/PLT (MPI) was calculated by dividing MPV by PLT. CRP levels (mg/l) were quantified via immunoturbidimetric analysis utilizing latex-enhanced particlesand PCT levels (ng/ml) by latex-enhanced immunoturbidimetric assay. Results In 25 (31.3%) of all 80 patients, no microorganisms were isolated (sterile cultures); in 28 (35%) resident microflora were isolated; in seven (8.8%) GNB were isolated; and in 17 (21.3%) GPB were isolated. CRP and Neu were significantly higher in patients with odontogenic abscesses compared to non-odontogenic ones. PLT and PCT were lower in patients with odontogenic abscesses vs those with non-odontogenic abscesses. Additionally, according to bacterial type, MPV, MPI and PCT were significantly higher in GPB compared to GNB. WBC, Neu and PLT were higher in patients with GNB vs GPB. Significant correlations were found between MPV andLy, and between MPV and Neu, regardless of the abscess origin or etiological factor. MPI exhibited an area under the curve of the receiver operating characteristic (AUC-ROC)=0.776, MPV of 0.541, and PCT of 0.568in distinguishing patients with GPB from GNB. A cut-off value of 0.029 was derived for MPI (70.6% sensitivity and 80% specificity). Conclusions This study highlights the impact of bacterial etiology on inflammatory and hematological markers in head and neck abscesses. Odontogenic abscesses showed higher CRP and Neu, indicating a stronger inflammatory response, while non-odontogenic abscesses had higher PLT, Ly, and PCT. MPI proved to be a more effective diagnostic marker (cut-off value of 0.029) than MPV or PCT for distinguishing between GPB and GNB, suggesting its valuable role in clinical practice for accurate and timely diagnosis.

A Comparative Study of Cystatin C and Creatinine as a Preliminary Marker of Nephropathy in Type 2 Diabetic Patients

Background: Type 2 diabetes disorder (T2DD) is one of the most common disorder in societies, and its causes are genetic and acquired. This disorder is characterized by an increase in the concentration of glucose in the blood. High concentrations of glucose in the blood for long periods lead to complications, the most important of which is diabetic nephropathy (DNP), which is characterized by the gradual loss of the kidney's filtration function.Material and methods: The present study was designed based on collecting twenty patients with newly DNP (as first group) and twenty healthy individuals (as second group). The levels of HbA1c, Creatinine and Cystatin C of all study individuals were measured using Chromatographic assay method, Kinetic colorimetric method and Immunoturbidimetric assay techniques respectively.Results: This study used the t-test statistical method to compare groups as well as sensitivity and specificity based on HbA1c, creatinine and Cystatin C biomarkers. The current study showed a higher the HbA1c percentage, creatinine level and Cystatin C level in the first group compared to the second group. On the other hand, the current study showed that Cystatin C has greater sensitivity and specificity than creatinine towards the DNP disease.Conclusion: The current study concluded by stating the importance of the role of Cystatin C as an early indicator of DNP disease, as the current study proved that Cystatin C has greater sensitivity and specificity than creatinine towards DNP disease

Interleukin-6 positively correlates with cardiovascular disease predictor algorithms and biomarker in rheumatoid arthritis patients.

Chronic inflammation is believed as the main culprit of the link between cardiovascular disease (CVD) and rheumatoid arthritis (RA). Interleukin-6 (IL-6) is a pro-inflammatory cytokine with a key role in RA pathophysiology and also correlates with joint destruction and disease activity. This study evaluates the association between IL-6 plasma level and cardiac biomarker NT-proBNP, HS-CRP, CVD predictor algorithms, Framingham Risk Score (FRS) and Systematic Coronary Risk Evaluation (SCORE), as well as with CXCL9 and its receptor, CXCR3 in RA patients compared to the controls. Sixty RA patients (30 early and 30 late) and 30 healthy persons were included in this study. IL-6 and NT-proBNP plasma levels were measured by the ELISA. Also, HS-CRP plasma levels were quantified using the immunoturbidimetric assay. The CVD risk was assessed by the FRS and SCORE. IL-6 plasma levels were significantly higher in the early and late RA patients compared to the controls (p < 0.001). There was a positive correlation between IL-6 with DAS-28 (p = 0.007, r = 0.346), BPS (p = 0.002, r = 0.396), BPD (p = 0.046, r = 0.259), SCORE (p < 0.001, r = 0.472), and FRS (p < 0.001, r = 0.553), and a negative association with HDL (p = 0.037, r = -0.270), in the patients. Also, IL-6 plasma level positively correlated with HS-CRP (p = 0.021, r = 0.297) and NT-proBNP (p = 0.045, r = 0.260) in the patients. Furthermore, a positive association was found between IL-6 plasma levels and CXCL9 (p = 0.002, r = 0.386), and CXCR3 (p = 0.018, r = 0.304) in the patients. Given the interesting association between IL-6 with various variables of CVD, IL-6 may be considered a biomarker for assessing the risk for future cardiovascular events in RA patients.

Longitudinal relationships between BMI and hs-CRP among people with schizophrenia

In people with schizophrenia (PwS), inflammation and metabolic issues significantly increase morbidity and mortality. However, our ability to understand inflammatory-metabolic mechanisms in this population has been limited to cross-sectional studies. This study involved 169 PwS and 156 non-psychiatric comparisons (NCs), aged 25–65, observed between 2012 and 2022 with 0 to 5 follow-ups post-baseline. High-sensitivity C-reactive protein (hs-CRP), a marker of inflammation, was measured via a particle-enhanced immuno-turbidimetric assay. Body mass index (BMI) was used as a proxy for metabolic function. The measurement intervals for hs-CRP and BMI ranged between 6 and 48 months. Linear mixed models (LMM) results revealed that at all time points, PwS has a higher hs-CRP (t (316) = 4.73, p < .001) and BMI (t (315) = 4.13, p < .001) than NCs; however, for BMI, this difference decreased over time (t (524) = −5.15, p < .001). To study interrelationships between hs-CRP and BMI, continuous time structural equational modeling (CTSEM) was used, accounting for uneven measurement intervals. CTSEM results showed that both hs-CRP predicted future BMI (Est. = 12.91, 95 % CI [7.70; 17.88]) and BMI predicted future hs-CRP (Est. = 1.54, 95 % CI [1.00; 2.04]), indicating a bidirectional relationship between inflammation and metabolic function. Notably, the influence of hs-CRP on future BMI was more robust than the other lagged relationship (p = .015), especially in PwS (Est. = 2.43, 95 % CI [0.39; 0.97]). Our study highlights the important role of inflammation in metabolic function and offers insights into potential interventions targeting inflammation in PwS.

Reference intervals and percentiles for soluble transferrin receptor and sTfR/log ferritin index in healthy children and adolescents.

Soluble transferrin receptor (sTfR) is a marker of both erythropoiesis and iron status and is considered useful for detecting iron deficiency, especially in inflammatory conditions, but reference intervals covering the entire pediatric age spectrum are lacking. We studied 1,064 (48.5 % female) healthy children of the entire pediatric age spectrum to determine reference values and percentiles for sTfR and the ratio of sTfR to log-ferritin (sTfR-F index) using a standard immunoturbidimetric assay. Soluble TfR levels were highly age-specific, with a peak in infancy and a decline in adulthood, whereas the sTfR-F index was a rather constant parameter. There were positive linear relationships for sTfR with hemoglobin (Hb) (p=0.008) and transferrin (females p<0.001; males p=0.003). Anegative association was observed between sTfR and ferritin in females (p<0.0001) and for transferrin saturation and mean corpuscular volume (MCV) in both sexes (both p<0.0001). We found a positive relationship between sTfR and body height, body mass index (BMI) and inflammatory markers (CrP p<0.0001; WBC p=0.0172), while sTfR-F index was not affected by inflammation. Soluble TfR values appear to reflect the activity of infant erythropoiesis and to be modulated by inflammation and iron deficiency even in a healthy cohort.

Method for quantifying free hemoglobin, distinct from the hemoglobin-haptoglobin complex, in human serum

The measurement of free hemoglobin (free Hb) in blood is crucial for assessing the risk of organ damage in patients with hemolytic diseases. However, the colorimetric method, commonly used in clinical practice, does not distinguish between free Hb and the hemoglobin-haptoglobin complex (Hb-Hp) in the blood, instead reflecting the total Hb level. Although size-exclusion high-performance liquid chromatography (SEC-HPLC) can specifically measure free Hb, its clinical use is limited by long assay times. Here, we developed a novel assay method for the rapid quantification of free Hb in serum, distinguishing it from Hb-Hp, using a latex agglutination immunoturbidimetric assay (LATIA). This method could be used to measure free Hb in sera in the range of 1–100 μg/mL in approximately 15 min using an automatic biochemistry analyzer. Using Hb-spiked serum samples from healthy adults, there was a high correlation with Hb levels determined using the newly developed method and SEC-HPLC, indicating a high specificity for free Hb. This novel assay can be used to monitor levels of free Hb in patients with various hemolytic diseases and to design therapeutic strategies based on measured values. However, further studies are required to assess its clinical performance.

Comparison of radial immunodiffusion, turbidimetric immunoassay, and Brix refractometry for determining bovine colostrum quality

Determining the concentration of IgG in colostrum is critical for assessment of colostrum quality. On-farm use of a Brix refractometer to estimate colostrum IgG concentration is widespread whereas radial immunodiffusion (RID) is the laboratory reference method. Turbidimetric immunoassay (TIA) might offer an alternative method to quantify IgG in colostrum, but the agreement with RID, as well as critical thresholds to determine high-quality colostrum remain uncertain. The objective of this study was to determine the level of agreement between RID, Brix %, and TIA for evaluation of colostrum quality. Composite colostrum samples (n = 58) from Holstein cows were evaluated using a digital Brix refractometer at the time of collection and stored at −20°C until analysis. The concentration of IgG was determined using RID and TIA. Data were analyzed using Passing-Bablok regression and Bland-Altman plots. Critical thresholds for TIA and Brix measurements to identify colostrum with an IgG concentration ≥ 50 and ≥ 100 g/L based on the reference method were determined using logistic regression and receiver operating characteristic curves. Results revealed that both TIA (Kendall's tau (Τ) = 0.91) and Brix % (Τ = 0.78) had a strong correlation with RID, respectively. Passing-Bablok regression identified a systematic [6.91 (4.33 to 8.98) g/L] and proportional [0.69 (0.67 to 0.72) g/L] bias between RID and TIA. The optimum threshold to identify samples with an IgG concentration ≥ 50 and ≥ 100 g/L were 40.6 g/L (area under the curve (AUC): 1.0; Sensitivity (Se): 100; Specificity (Sp): 100) and 85.8 g/L (AUC: 0.99; Se: 96.6; Sp: 96.6) for TIA and 18.4% (AUC: 1.0; Se: 100; Sp: 100) and 25.8% (AUC: 0.99; Se: 82.8; Sp: 93.1) for Brix %, respectively. Using the identified thresholds, our results show that both Brix and TIA were highly accurate for identifying high-quality colostrum, but because of a proportional bias, direct comparison of IgG concentration results obtained by RID and TIA are cautioned.