Measurement uncertainty in clinical chemistry: ISO 20914 versus nordtest or intermediate precision versus bias.

AIM: Measuring uncertainty (MU) is crucial to ensure the accuracy and precision of laboratory results. This study compares the ISO 20914 and Nordtest guidelines to analyze the MU values for 20 clinical chemistry analytes over six months. METHODS: The researchers calculated MU components, including within-laboratory reproducibility (Rw), laboratory analytical performance bias (u(bias)), and combined standard uncertainty (uc), based on internal quality control and external quality assessment data. The final expanded uncertainty (U) values were determined by multiplying the combined uncertainty with a coverage factor (k = 2 for 95% Confidence Interval), following each guideline's respective procedures. Clinical chemistry analytes were analyzed on Roche Cobas 6000 c501 auto analyzer (Roche Diagnostics, Mannheim, Germany) and manufacturer's kits were used analysis. RESULTS: The results show that 11 out of 20 clinical chemistry analytes met the targeted maximum allowable measurement uncertainty (MAU) values when calculated according to ISO 20914 guideline. Also, 11 out of 20 clinical chemistry analytes' MU values met the MAU values with the Nordtest guideline's recommended calculations. However, some tests met the MAU in the ISO 20914 approach but not in the Nordtest guideline, and vice versa. CONCLUSIONS: The study found that intermediate precision (uRw) in the ISO 20914 approach and performance bias (u(bias)) in the Nordtest approach significantly impacted MU values. The research highlights the importance of standardization in MU calculation approaches across clinical laboratories. These findings have implications for patient care and clinical decision-making, emphasizing the importance of selecting appropriate laboratory guidelines for routine use.

Could S-Monovette Serum Gel Tubes be Used for Clinical Chemistry Analysis Instead of Serum Separator Tube II Advance?

BACKGROUND: We aimed to compare the Sarstedt S-Monovette serum gel tube and the BD (Becton, Dickinson and Company) Serum Separator Tube II (SST II) Advance based on technical specifications and tests results. METHODS: One hundred and twenty volunteers were included in the technical evaluation and 42 of 120 volunteers in the clinical evaluation. Blood was collected into S-Monovette, and SST II. Twelve quality indicators (QI) were determined for technical evaluation. For clinical evaluation, 29 clinical chemistry analytes were analysed simultaneously on a Roche Cobas 6000 c501 (Roche Diagnostics, Mannheim, Germany). Calculations were made using the formula suggested by the EFLM according to the QIs. If the difference between S-Monovette and SST II was < 1%, S-Monovette was considered sufficient for relevant QI. For clinical evaluation, Passing Bablok regression analysis and Bland-Altman plots were used. Desirable bias values for comparison with mean percentage difference (MPD) were obtained from biological variation databases. RESULTS: S-Monovette tubes were found to be suitable for all QIs (difference < 1%). No significant differences were observed in analytes except lactate dehydrogenase (LDH). LDH results (U/L) obtained from the SST II were statistically significantly higher (SST II: 201 ± 42, S-Monovette: 195 ± 35, regression equation was y = 31.4 + 0.8x). The MPD of LDH (2.4%) remained within the desirable bias (3.4%); however, the 95% CI of the MPD of LDH (0.5% - 4.4%) exceeded the desirable bias. CONCLUSIONS: S-Monovette has been deemed appropriate for use in clinical chemistry analysis, as the MPD of LDH and other analytes remained within the bias limits. The LDH was considered sensitive to microhemolysis as a possible reason for the difference in LDH results.

Interferograms plotted with reference change value (RCV) may facilitate the management of hemolyzed samples.

Background: The European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) Working Group for Preanalytical Phase (WG-PRE) have recommended an algorithm based on the reference change value (RCV) to evaluate hemolysis. We utilized this algorithm to analyze hemolysis-sensitive parameters. Methods: Two tubes of blood were collected from each of the 10 participants, one of which was subjected to mechanical trauma while the other was centrifuged directly. Subsequently, the samples were diluted with the participant's hemolyzed sample to obtain the desired hemoglobin concentrations (0, 1, 2, 4, 6, 8, and 10 g/L). ALT, AST, K, LDH, T. Bil tests were performed using Beckman Coulter AU680 analyzer. The analytical and clinical cut-offs were based on the biological variation for the allowable imprecision and RCV. The algorithms could report the values directly below the analytical cut-off or those between the analytical and clinical cut-offs with comments. If the change was above the clinical cut-off, the test was rejected. The linear regression was used for interferograms, and the hemoglobin concentrations corresponding to cut-offs were calculated via the interferograms. Results: The RCV was calculated as 29.6% for ALT. Therefore, ALT should be rejected in samples containing >5.9 g/L hemoglobin. The RCVs for AST, K, LDH, and T. Bil were calculated as 27.9%, 12.1%, 19.2%, and 61.2%, while the samples' hemoglobin concentrations for test rejection were 0.8, 1.6, 0.5, and 2.2 g/L, respectively. Conclusions: Algorithms prepared with RCV could provide evidence-based results and objectively manage hemolyzed samples.

Could Some Laboratory Parameters Predict Mortality in COVID-19?

BACKGROUND: The number of confirmed cases of COVID-19 continues to increase worldwide and threatens public health. Our aim in this study is to examine the relationship between some laboratory parameters and hematological ratios with the severity of the disease and hospital mortality. METHODS: This study was designed as a retrospective cohort. The clinical data of 743 COVID-19 diagnosed patients who were eligible for hospitalization between March 16, and May 15, 2020 analyzed, retrospectively. The patients were separated into two groups as discharged from hospital (n = 681) and dead in hospital (n = 62). ROC curves and cutoff values of NLR (Neutrophil/Lymphocyte Ratio), PLR (Platelet/Lymphocyte Ratio), MLR (Monocyte/ Lymphocyte Ratio), CRP, and ferritin upon admission to hospital were calculated for the two groups. Binary Logistic Regression used to determine independent risk factors for mortality. RESULTS: The difference between both groups for age, duration in hospital, WBC, neutrophil, lymphocyte, NLR, PLR, MLR, CRP, and ferritin values were statistically significant. NLR had the highest area under the curve with a cutoff of 5.5 in the ROC curve [(AUC: 0.892, 95% CI: 0.844 - 0.939); Sensitivity = 85%, Specificity = 84%]. NLR, MLR, PLR, CRP and Ferritin groups have significant effects on the survival times of the Covid-19 patients. According to logistic regression analysis, increments of NLR (OR = 18.1, 95% CI: 6.4 - 51.4), CRP (OR = 5.5, 95% CI: 2.5 - 12.2), and age (OR = 2.7 95% CI: 1.3 - 5.5) values proportionally increase the death probability. CONCLUSIONS: NLR, CRP, and age are independent risk factors for mortality from COVID-19. We believe that evaluating these parameters together during diagnosis will be important in predicting the prognosis of the disease and in treatment approaches.

Relationship Between Plasma Levels of Soluble CD40 Ligand and the Presence and Severity of Isolated Coronary Artery Ectasia.

OBJECTIVE: We aimed to investigate whether soluble CD40 ligand (CD40L) levels are higher in patients with isolated coronary artery ectasia (CAE) compared to patients with angiographically normal coronary arteries and those with stable coronary artery disease (CAD). MATERIALS AND METHODS: In all, 55 patients with isolated CAE without stenosis, 55 with stable CAD, and 55 control participants with angiographically normal coronary arteries were included. The CAE severity was determined according to the Markis classification. Plasma levels of soluble CD40 ligand were measured by enzyme-linked immunosorbent assay. RESULTS: The baseline characteristics of the 3 groups were similar. Plasma levels of soluble CD40 ligand were significantly higher in patients with CAE and CAD than in controls (2.6 ± 3.1 ng/mL and 2.0 ± 3.1 ng/mL vs 1.8 ± 2.1 ng/mL, P = .004). No difference was found between the CAE and CAD groups. Soluble CD40 ligand level was significantly higher in the type 1 Markis subgroup than that in the type 3 or type 4 subgroups ( P = .01). A receiver operating characteristic curve analysis revealed that soluble CD40 ligand level >1.2 ng/mL identified patients with isolated CAE. CONCLUSION: Significantly higher levels of soluble CD40 ligand were detected in patients with CAE than that in control participants with normal coronary arteries, suggesting that soluble CD40 ligand may be involved in the pathogenesis of CAE. The CD40-CD40 ligand system likely plays a role in the pathogenesis of CAE.

Serum paraoxonase, TAS, TOS and ceruloplasmin in brucellosis.

UNLABELLED: It is possible that brucellosis may be related to increase free radical production and antioxidant depletion. Thus, in the present study we aimed to evaluate the oxidative status in patient with brucellosis and healthy controls. METHODS: This study includes the patients with brucellosis diagnosed by clinical findings and positive agglutination titer. The paraoxonase, ceruloplasmin, total antioxidant capacity and total oxidant status values were measured from the samples taken. The oxidative stress index value was calculated through the total antioxidant capacity and total oxidant status values. RESULTS: A total number of 93 people, 40 women (43%) and 53 men (57%) were included to the study. The levels of ceruloplasmin were found higher in patients when compared to the control group (p < 0.001). The total antioxidant capacity level was found significantly higher in the patients group when compared to the control group (p < 0.001). The oxidative stress index value was significantly lower in the patients group when compared to the control group (p < 0.001). The paraoxonase-1 level was not different in control and patient groups (p = 0.077). CONCLUSIONS: Brucellosis is an infection that is frequently seen in Mediterranean countries. This infection breaks the oxidant and antioxidant balance. In this disease, oxidant-antioxidant system indicators such as ceruloplasmin, total antioxidant capacity, total oxidant status and oxidative stress index can be used for showing the role of the brucella infection and for the monitoring of the treatment results.

Effects of repeated desflurane and sevoflurane anesthesia on enzymatic free radical scavanger system.

BACKGROUND: To investigate the possible effects of repeated sevoflurane and desflurane anesthesia on hepatocellular system by evaluating the free radical metabolism, hepatocellular enzymes and histopatholgical changes in rats. METHODS: Four groups of animals were studied. Sevoflurane 2% (v/v) and desflurane 6% (v/v) in air/O2 were administered to animals in group II (n=9) and III (n=9) respectively. 100% (v/v) O(2) was administered in group IV (n=9). Administration was done for 60 minutes over 3 days. Nine animals were allocated to control group (group I), superoxide dismutase (SOD), catalase (CAT), glutathion peroxidase (GSH-Px), glutathione-s-transferase (GST) and thiobarbituric acid reactive substances (TBARS) were studied. Also electron microscopy was performed. RESULTS: Catalase, SOD, GSH-Px, GST activities and TBARS levels were significantly higher in groups II and III than in group I (p<0.05). All parameters were significantly higher in groups II versus group IV (p<0.05). On the other hand, SOD, GSH-Px and GST activities were significantly elevated in group III than IV, but CAT activity and TBARS levels were not significantly. Catalase, SOD, GSH-Px, GST but not TBARS levels were significantly higher in groups II and III than in group IV (p<0.05). TBARS levels were higher in group III than in group IV, but this elevation was not statistically significant. CAT, SOD and GSH-Px activities were significantly higher in groups II than in group III (p<0.05). CONCLUSION: Although electron microscopy findings were similar for group II and III, we can conclude that sevoflurane might cause more cellular damage than desflurane by causing higher activation of free radical metabolising enzymes.

Investigation of free radical scavenging enzyme activities and lipid peroxidation in human placental tissues with miscarriage.

BACKGROUND: Miscarriage (early pregnancy failure) is a pregnancy-related disease, the pathophysiology of which is still not completely understood. Lipid peroxidation and alterations in antioxidant enzyme activities may be of importance in the pathogenesis of this disorder. This study was planned to investigate the possible relation between free radical scavenging enzyme activities and lipid peroxidation levels in placenta tissues with miscarriage. METHODS: Placental tissue samples were obtained from 21 patients who had miscarried and 25 normal pregnant women undergoing elective abortion as a control group. Total superoxide dismutase (T-SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) enzyme activities and levels of thiobarbituric acid reactive substances (TBARS), antioxidant potential (AOP), and nonenzymatic superoxide radical scavenger activity (NSSA) were measured in the placental tissues. RESULTS: GSH-Px, CAT activities, and TBARS levels were found to be significantly increased, while T-SOD and NSSA values decreased in patients with early pregnancy failure when compared with women undergoing elective abortion (control group). However, there were no significant differences in AOP levels between the groups. CONCLUSIONS: Our results reflect oxidative stress in placenta tissues of early pregnancy failure, as the oxidative processes seem to be counteracted by the physiologic activation of antioxidant enzymes such as CAT and GSH-Px. Moreover, a compensatory mechanism might be developed against possible oxidative damage in patients with miscarriage.