APS calculator: a data-driven tool for setting outcome-based analytical performance specifications for measurement uncertainty using specific clinical requirements and population data.

OBJECTIVES: According to ISO 15189:2022, analytical performance specifications (APS) should relate to intended clinical use and impact on patient care. Therefore, we aimed to develop a web application for laboratory professionals to calculate APS based on a simulation of the impact of measurement uncertainty (MU) on the outcome using the chosen decision limits, agreement thresholds, and data of the population of interest. METHODS: We developed the "APS Calculator" allowing users to upload and select data of concern, specify decision limits and agreement thresholds, and conduct simulations to determine APS for MU. The simulation involved categorizing original measurand concentrations, generating measured (simulated) results by introducing different degrees of MU, and recategorizing measured concentrations based on clinical decision limits and acceptable clinical misclassification rates. The agreements between original and simulated result categories were assessed, and values that met or exceeded user-specified agreement thresholds that set goals for the between-category agreement were considered acceptable. The application generates contour plots of agreement rates and corresponding MU values. We tested the application using National Health and Nutrition Examination Survey data, with decision limits from relevant guidelines. RESULTS: We determined APS for MU of six measurands (blood total hemoglobin, plasma fasting glucose, serum total and high-density lipoprotein cholesterol, triglycerides, and total folate) to demonstrate the potential of the application to generate APS. CONCLUSIONS: The developed data-driven web application offers a flexible tool for laboratory professionals to calculate APS for MU using their chosen decision limits and agreement thresholds, and the data of the population of interest.

Comparison of the ELISA method with the nephelometric method for determination of serum amyloid A in patients with COVID 19.

This study aimed to examine the agreement of the serum amyloid A (SAA) values determined using the ELISA test and the nephelometric automated method. This study included 80 serum samples obtained from patients with COVID-19. Samples were determined using ELISA and the nephelometric method. Wilcoxon signed ranks test showed a statistically significant difference in the calculated median values (Z = -2.432, p = 0.015). The correlation between methods was statistically significant (r = 0.603, p < 0.0001). Bland Altman analysis showed a bias of 56.6 mg/L and a relative bias of 7.4% between the methods. The results of this study indicate that further studies are needed that will examine the compliance between the ELISA and the nephelometric method for determining SAA, and the results must be carefully interpreted based on the method used.

An approach for determining allowable between reagent lot variation.

Clinicians trust medical laboratories to provide reliable results on which they rely for clinical decisions. Laboratories fulfil their responsibility for accurate and consistent results by utilizing an arsenal of approaches, ranging from validation and verification experiments to daily quality control procedures. All these procedures verify, on different moments, that the results of a certain examination procedure have analytical performance characteristics (APC) that meet analytical performance specifications (APS) set for a particular intended use. The APC can in part be determined by estimating the measurement uncertainty component under conditions of within-laboratory precision (uRw), which comprises all components influencing the measurement uncertainty of random sources. To maintain the adequacy of their measurement procedures, laboratories need to distinguish aspects that are manageable vs. those that are not. One of the aspects that may influence uRw is the momentary significant bias caused by shifts in reagent and/or calibrator lots, which, when accepted or unnoticed, become a factor of the APC. In this paper, we postulate a model for allocating a part of allowable uRw to between-reagent lot variation, based on the need for long-term consistency of the measurement variability for that specific measurand. The allocation manages the ratio between short-term and long-term variation and indicates laboratories when to reject or correct certain variations due to reagent lots.

Effects of short-term magnesium supplementation on ionized, total magnesium and other relevant electrolytes levels.

This study aimed to investigate the short-term effects of three magnesium (Mg) dietary supplements containing mineral immediately available for absorption on Mg biochemical status indices (ionized and total Mg), as well as their effects on electrolytes levels in healthy female young adults (n = 61). After a 10-days intervention period supplementation with powder/granulate containing Mg oxide led to an increase in both ionized Mg concentration and % in total Mg in comparison with the baseline. Supplementation with Mg citrate was associated with the significant increase in % of ionized fraction and decrease in serum total Mg concentration. By contrast, among participants consuming Mg carbonate in the form of effervescent tablets ionized Mg concentration and % in total Mg decreased, without detectable changes in serum total Mg. In conclusion, after the short-term supplementation period, Mg oxide demonstrated superior bioavailability compared to the other examined Mg supplements without affecting other minerals' levels.

Measurement uncertainty as a universal concept: can it be universally applicable in routine laboratory practice?

Measurement uncertainty (MU) of results is one of the basic recommended and accepted statistical methods in laboratory medicine, with which analytical and clinical evaluation of laboratory test quality is assessed. Literature data indicate that the calculation of MU is not a simple process, but that its assessment in daily laboratory practice should be reduced to routine and simple presentation, understandable to both laboratory professionals and physicians. In order to achieve this, it is necessary to understand the purpose of the test for which MU is to be determined. Various suggestions have been given for presentation of MU as a quantitative indicator of the quality of the final measurement result in the medical laboratory. Although MU refers to the final measurement result, this metrological concept reflects the entire laboratory measurement process. The data on estimated MU is used to interpret the measured numerical result, and represents quantitatively the quality of the measurement itself, i.e. how different are the results of multiple measurements of the analyte of interest in the same sample, as well as whether the method of determination itself is subjected to significant random and systematic deviation. Initially, in the metrological concept, the MU is viewed in relation to the true value of the analyte of interest. However, the true value of the analyte measured in the biological fluid matrix of the study population cannot be known. It is therefore considered the closest value obtained by the perfect method, for which the bias and inaccuracy, as measures of systematic and random error, are equal to zero, which is practically impossible to achieve in routine laboratory practice. Although current standards require accredited medical laboratories to estimate MU, none of these guidelines provide clear guidance on how this can be achieved in daily laboratory work. This review examines literary data and documents dealing with MU issues, but also highlights what additional terms and data should be considered when interpreting MU. This paper ultimately draws attention, and once again points out, that a simpler solution is needed for this universal concept to be formally and universally applicable in routine laboratory medicine practice.

Stress hormones at rest and following exercise testing predict coronary artery disease severity and outcome.

OBJECTIVES: Despite considerable knowledge regarding the importance of stress in coronary artery disease (CAD) pathogenesis, its underestimation persists in routine clinical practice, in part attributable to lack of a standardized, objective assessment. The current study examined the ability of stress hormones to predict CAD severity and prognosis at basal conditions as well as during and following an exertional stimulus. MATERIALS AND METHODS: Forty Caucasian subjects with significant coronary artery lesions (≥50%) were included. Within 2 months of coronary angiography, cardiopulmonary exercise testing (CPET) on a recumbent ergometer was performed in conjunction with stress echocardiography (SE). At rest, peak and after 3 min of recovery following CPET, plasma levels of cortisol, adrenocorticotropic hormone (ACTH) and NT-pro-brain natriuretic peptide (NT-pro-BNP) were measured by immunoassay sandwich technique, radioimmunoassay, and radioimmunometric technique, respectively. Subjects were subsequently followed a mean of 32 ± 10 months. RESULTS AND DISCUSSION: Mean ejection fraction was 56.7 ± 9.6%. Subjects with 1-2 stenotic coronary arteries (SCA) demonstrated a significantly lower plasma cortisol levels during CPET compared to those with 3-SCA (p < .05), whereas ACTH and NT-pro-BNP were not significantly different (p > .05). Among CPET, SE, and hormonal parameters, cortisol at rest and during CPET recovery demonstrated the best predictive value in distinguishing between 1-, 2-, and 3-SCA [area under ROC curve 0.75 and 0.77 (SE = 0.11, 0.10; p = .043, .04) for rest and recovery, respectively]. ΔCortisol peak/rest predicted cumulative cardiac events (area under ROC curve 0.75, SE = 0.10, p = .049). CONCLUSIONS: Cortisol at rest and following an exercise test holds predictive value for CAD severity and prognosis, further demonstrating a link between stress and unwanted cardiac events.

Indirect estimation of reference intervals for thyroid parameters.

BACKGROUND: The aim of this work was to determine indirect reference intervals from patients' results obtained during routine laboratory work. This could be an accurate alternative to the laborious and expensive job of producing reference intervals for populations according to international recommendations. METHODS: All the results for thyrotropin (TSH), total and free thyroxine, and triiodothyronine (T4, fT4, T3, and fT3) stored in our laboratory information system between 2008 and 2011 were included in this study. We used logarithmic transformation of the raw data to exclude outliers. After visual observation of the data distribution, we estimated non-parametric reference intervals. A standard normal deviation test was performed to test the significance of differences between subgroups. RESULTS: There was no significant difference in the serum levels of the analyzed thyroid parameters, so we calculated combined reference values. However, we found a significant difference in TSH values between ambulatory and hospitalized patients, but only in 2011. Indirect reference values for TSH, T4, fT4, T3 and fT3 were 0.42 - 3.67 mIU/L, 66.0 - 136.10 nmol/L, 10.20 - 18.40 pmol/L, 1.10 - 2.39 nmol/L, and 3.17 - 5.59 pmol/L, respectively. CONCLUSIONS: The indirect determination of laboratory-specific reference intervals using patients' laboratory data is a relatively easy and inexpensive method. Also, indirect reference limits will be more precise and true if skewness and kurtosis of the distribution are not too large.

Indirect estimation of age-related reference limits of thyroid parameters: a cross-sectional study of outpatients' results.

OBJECTIVES: Defining adequate reference limits (RLs) for thyroid hormones is an important task for support monitoring and the treatment of subclinical thyroid disease. We determined whether there are age-related RLs for thyroid parameters in male and female outpatients free of overt thyroid disease. DESIGN: We analyzed 22,860 results (11,440 male and 11,420 female outpatients above the age of 18) for thyrotropin (TSH), free thyroxine (fT4) and total triiodothyronine (T3) that were stored in our laboratory information system between 2008 and 2011. We calculated the 2.5th and 97.5th centiles for the analyzed thyroid parameters. RESULTS: Our results indicate higher TSH levels with ageing, with a significant difference (p < 0.05) between the 97.5th centiles for males and females older than 70 (5.07 mIU/L and 4.10 mIU/L), but also a significant difference between male and female fT4 from 31 to 40 and from 41 to 50 years old (18.4 vs 14.9 pmol/L and 19.0 vs 15.9 pmol/L, p < 0.05), respectively. Overall indirect estimates of the 97.5th centiles for TSH for males and females were not significantly different and were below the generally recommended upper limit (4.01 mIU/L and 4.20 mIU/L, respectively). In addition, we found no statistically significant change in mean T3 values in the analyzed population. CONCLUSIONS: This cross-sectional study indicates change in TSH and fT4 levels with ageing and gender-related upper limits. This suggests that by using indirect estimation a laboratory could provide clinicians with more accurate gender- and age-specific RLs for thyroid parameters.

Beneficial effects of a new probiotic formulation on adipocytokines, appetite-regulating hormones, and metabolic parameters in obese women.

Obesity is often accompanied by low-grade chronic inflammation and metabolic syndrome. It has been established that microbiota influences many physiological processes, including the development of obesity, and dysbiosis has been observed in obese individuals. In this study, we aimed to evaluate the impact of a new probiotic formulation, containing two probiotic strains and the bioactive compound octacosanol, on body weight, metabolic parameters, and concentrations of certain adipocytokines and appetite-regulating hormones in obese women. This double blind placebo-controlled supplementary intervention study included twenty-five women in the intervention group and twenty-three in the placebo group, and it lasted 12 weeks. Daily oral supplementation included 7 × 1010 CFU of Lactiplantibacillus plantarum 299v (DSM9843), 5 × 109 CFU of Saccharomyces cerevisiae var. boulardii (DBVPG6763), and 40 mg of octacosanol or placebo. Body weight, metabolic parameters, adipocytokines, and appetite-regulating hormones were assessed before (T0) and after the intervention (T1). After the intervention, significantly lower median concentrations of CRP (p = 0.005) and IL-6 (p = 0.012) were measured in the intervention group than the baseline, while the median concentrations of ghrelin (p = 0.026) and HDL-cholesterol (p = 0.03) were significantly increased. The intervention group had lower CRP levels (p = 0.023) and higher ghrelin levels (p = 0.006) than the placebo group. Significant changes in BMI between groups were not observed. In summary, although the new probiotic formulation showed beneficial effects on IL-6, CRP, HDL, and ghrelin levels, its potential effects on regulating triglyceride, insulin, and glucose levels require further studies before the novel dietary intervention could be considered a useful adjuvant therapy and an effective strategy for the management of obesity and obesity-associated comorbidities.

Measurement uncertainty.

Over time, the metrological concept of uncertainty in measurement has been very successfully integrated into laboratory sciences. For proper implementation, an understanding of specific metrology terminology and additional concepts such as metrology traceability and commutability is necessary. Although the original thinking about measurement uncertainty in laboratory medicine suggests the complexity of the concept, it basically refers to the result as the end product of the entire laboratory process. Although the data on measurement uncertainty can be expressed quantitatively, the basis of this concept is the continuous evaluation of all phases of the laboratory process. This means that laboratory experts should keep in mind that the extra-analytical phases (on which the uncertainty of the measurement results may depend the most) must be continuously monitored. The analytical phase can be "held in check" by established internal and external quality control processes. It is the internal/external quality control data that is used to calculate the numerical value of the measurement uncertainty of the measurement results. Although over time the awareness of laboratory experts regarding the concept of measurement uncertainty has increased, there are still many challenges that need to be followed, and the last one is how to achieve a balance between understanding, evaluation process and application of measurement uncertainty data of measurement results for complete and ultimate practical use.

The utility of serum amyloid A and other acute-phase reactants determination in ambulatory care COVID-19 patients.

Background: The unpredictable course of Coronavirus Disease 19 (COVID-19) is making good severity assessment tools crucial. This study aimed to assess the usefulness of serum amyloid A (SAA) and other acute-phase reactants (APRs) in ambulatory care COVID-19 patients and identified relationships between these markers and disease outcomes. Methods: From August to November 2020, patients seen in the outpatient department of the Clinic for Infectious and Tropical Diseases (Belgrade, Serbia) with confirmed COVID-19 were included. Patients were classified into mild, moderate, and severe disease groups based on World Health Organization criteria. SAA, C-reactive protein (CRP), interleukin-6 (IL-6), procalcitonin (PCT), ferritin, fibrinogen, D-dimer, albumin, and transferrin were measured. The median values of all APRs were compared between COVID-19 severity groups, hospitalized and non-hospitalized patients, and survivors and non-survivors. The Receiver operator characteristic (ROC) curve analysis was used for the classification characteristics assessment of individual APRs for the severity of illness, hospitalization, and survival.

Oxidative stress-related risk of the multiple sclerosis development.

Background: Multiple sclerosis (MS) is characterized by inflammation, demyelination and axonal degeneration. Oxidative stress (OS) plays a significant role in the pathogenesis of the disease. The aim of the study was to examine the association between OS and smoking on the MS development. Methods: The study included 175 patients with relapsing-remitting multiple sclerosis (RRMS) (76 males, 99 females) and 254 healthy subjects (81 males and 173 females). Oxidative stress biomarkers in serum, Total Antioxidant Status (TAS) and Total Oxidative Status (TOS) were determined spectrophotometrically. Oxidative Stress Index (OSI) was calculated as the ratio of TOS and TAS. Urinary 8-oxo7,8-dihydro-2'-deoxyguanosine were determined by HPLC-MS/MS and expressed as 8-oxodG/creatinine. Results: In females with RRMS were higher TOS, OSI and 8-oxodG/creatinine than in females in control group. The group of males with RRMS had lower level of TAS than the males in control group. Higher levels of 8-oxodG/creatinine was obtained in active, passive and former smokers with RRMS than in control group with the same exposition to tobacco smoke. Independent predictors of MS are passive smoking, increased OSI and increased levels of urinary 8-oxodG/creatinine. Conclusions: Our results demonstrate that the OS parameters should be included in the assessment of the risk for MS development. Due to the more sensitivity to oxidative stress, females may be at higher risk of MS development. This data indicates the importance of introducing the antioxidant therapy as a complementary treatment in patients with RRMS.

Is alumina suitable for solid phase extraction of catecholamines from brain tissue?

Occupational and environmental toxicology specialists find catecholamine fluctuations in brain tissue relevant for research of neurotoxicity, such as that induced by manganese or zinc, pesticides, industrial solvents, plastic, air pollution, or irradiation. Considering that catecholamine tissue concentrations are generally very low, their extraction requires a reliable and optimal method that will achieve maximum recovery and minimise other interferences. This study aimed to evaluate whether the aluminium (III) oxide (Al2O3, alumina) based cartridges designed for catecholamine isolation from plasma could be used for solid-phase extraction (SPE) of catecholamine from the brain tissue. To do that, we homogenised Wistar rat brain tissue with perchloric acid and compared three extraction techniques: SPE, the routine filtration through a 0.22 µm membrane filter, and their combination. In the extracts, we compared relative chromatographic catecholamine mobility measured with high performance liquid chromatography with electrochemical detection. Chromatographic patterns for norepinephrine and epinephrine were similar regardless of the extraction technique, which indicates that the alumina cartridge is good enough to isolate them from brain tissue. However, the dopamine pattern was unsatisfactory, and further experiments are needed to identify the issue and optimise the protocol.

Vitamin D Serum Levels and Vitamin D Receptor Genotype in Patients with Parkinson's Disease.

BACKGROUND: Vitamin D is a steroid hormone, known to be involved in the pathogenesis of various neurodegenerative disorders, including Parkinson's disease (PD). We aimed to clarify the relationship between hypovitaminosis D and the predisposition for PD and its clinical presentation. An additional aim was to examine the specific gene polymorphisms associated with vitamin D level. MATERIAL AND METHODS: Total level of 25(OH)-vitamin D (25(OH)D) was measured in the serum of parkinsonian patients (n = 113) and controls (n = 82) using a commercial immunoassay. Genetic analyses were performed using Taqman assays on Real Time PCR amplification system. RESULTS: Higher frequency of vitamin D deficiency (<50 nmol/L) was observed in PD patients, compared to controls (40.7% and 23.2%, respectively, P = 0.010). It was also a positive predictive marker of PD (OR, 2.27; 95% CI, 1.206-4.298; P < 0.011). Significantly higher UPDRS (35.85 ± 1.35 and 32.09 ± 0.99, respectively, P = 0.023) and HY scores (2(1.5-2.5) and 1.5(1.0-2.0), respectively, P = 0.005) were present in patients with 25(OH)D level < 50 nmol/L compared to patients with 25(OH)D level ≥ 50 nmol/L. Despite some trends observed, differences in allelic and genotypic distribution between controls and patients, as well as between subgroups, did not reach the level of significance (P > 0.05). CONCLUSIONS: Findings of this study confirm the hypothesis of a significant relationship between hypovitaminosis D and PD. We demonstrated higher prevalence of vitamin D deficiency in PD patients, as well as its predictive potential for the onset and progression of PD.

How Supplementation with SOD-Rich Plant Extract, Combined with Gliadin, Can Affect Oxidative Stress Markers and Zonulin Levels in Exercise-Induced Oxidative Stress.

A randomized, double-blind, placebo-controlled study was conducted to investigate the influence of supplementation with a superoxide dismutase (SOD)-rich plant extract on markers of oxidative stress, zonulin levels and the performance of elite athletes. Participants were 30 international-level rowers, divided into an experimental group (n = 15) and a control group (n = 15). The rowers performed a maximal effort incremental test on a rowing ergometer at the beginning and at the end of the study. Markers of oxidative stress (total antioxidant status (TAS), total oxidant status (TOS), oxidative stress index (OSI), superoxide dismutase (SOD), glutathione peroxidase (GPx), advanced oxidation protein products (AOPPs), malondialdehyde (MDA), sulfhydryl (SH) groups, bilirubin, uric acid, albumin and zonulin) were determined in serum. A lower TOS (p = 0.010) and OSI (p = 0.004), a lower MDA (p = 0.001) and a higher level of SH groups (p = 0.031) were observed in the experimental group after supplementation. Physical performance was evaluated through metabolic efficiency, taking lactate levels and power output on the ergometer into account. After 6 weeks of supplementation, the relative increase in metabolic efficiency at a 4 mmol/L lactate concentration and maximal effort was significantly higher in the experimental group (p = 0.004 and p = 0.015, respectively). These results suggest that supplementation with a SOD-rich extract promotes lower oxidative stress, better antioxidant protection and, consequently, the better work performance of athletes.

Epigenetic Aspects of a New Probiotic Concept-A Pilot Study.

Several studies report the important role of an altered gut microbiota in the development of obesity, highlighting the potential use of probiotics in the treatment of obesity. The aim of this study is to investigate the effect of a novel probiotic approach on the expression of specific miRNAs and mRNAs associated with obesity in combination with the hypocholesterolemic octacosanol. Twenty overweight/obese women participated in a randomized, placebo-controlled, double-blind study and were randomly divided into two groups: the intervention group (daily one capsule containing Lactobacillus plantarum 299v (DSM9843), Saccharomyces cerevisiae var. boulardii, and 40 mg octacosanol; N = 12) and the placebo group (N = 8). Changes in lipid parameters and expression of miRNAs and mRNAs were assessed before (T0) and after the 12-week intervention (T1). After the intervention, the expression of miR-155-5p (9.38 ± 0.85 vs. 8.38 ± 1.06, p = 0.05) and miR-24-3p (3.42 ± 0.38 vs. 2.71 ± 0.97, p = 0.031) showed significant decreases in the intervention group when compared to the control group. At T1, the expression of miR-155-5p (8.69 ± 1.31 vs. 9.3 ± 0.85, p = 0.04), miR-125b-5p (5.41 ± 1.18 vs. 5.99 ± 1.36, p = 0.049), and TNF-α (10.24 ± 1.66 vs. 11.36 ± 1.12, p = 0.009) were significantly decreased in the intervention group. No changes in lipids and anthropometric parameters were observed. The novel probiotic approach had a positive effect on regulating the expression of certain miRNAs and mRNAs important for regulating inflammation and adipogenesis, which are essential for obesity onset and control.

Correlation of bone alkaline phosphatase and iPTH with some basic biochemical markers in predialysis and dialysis patients.

BACKGROUND: Bone alkaline phosphatase (BALP) is a direct and independent indicator of impaired bone turnover. We intended to find out whether there are any significant changes in BALP and iPTH levels, in comparison to total Ca, total Mg, inorganic P, total alkaline phosphatase (ALP), and tartrate resistant acid phosphatase (TRAP) in predialysis and dialysis patients. METHODS: Out of 266 patients investigated, 114 were on continuous ambulatory peritoneal dialysis, 112 were on maintenance haemodialysis, while 40 predialysis patients had end stage renal disease. The parameters were analysed according to the manufacturers' instructions. RESULTS: Correlations were established for the bone marker concentrations analysed among the studied groups. The largest ranges were determined for BALP and iPTH. Predialysis and dialysis patients showed very low levels of BALP. Dialysis patients had lower levels of iPTH (p < 0.001), while in predialysis patients the levels were significantly higher (p < 0.05) than recommended for low bone turnover, according to K/DOQI. CONCLUSIONS: The observations made in this study identify BALP as a good indicator of decreased bone turnover in predialysis and dialysis patients. However, in order to reveal a difference between bone activity and the level of parathyroid activity and its effect on bone turnover, it is always necessary to observe both BALP and iPTH levels.

The Effects of Disease-Modifying Therapies on Oxidative Stress in Patients With Relapsing-Remitting Multiple Sclerosis.

OBJECTIVE: Oxidative stress (OS) has a role in the pathogenesis and progression of multiple sclerosis. The effects of disease-modifying therapies (DMTs) on OS are unclear. We aimed to explore the association between DMTs and OS in patients with relapsing-remitting multiple sclerosis (RRMS). METHODS: The study conducted in 167 patients (102 received and 65 not received the DMTs). The DMTs included interferon beta-1a (n = 15), interferon beta-1b (n = 20), glatiramer acetate (n = 10), and sphingosine-1-phosphate receptor modulators (n = 57). Oxidative stress assessed by total antioxidant status (TAS) and total oxidant status (TOS) (determined by spectrophotometric method), oxidative index (OSI was calculated), and urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG/creatinine was determined by high-performance liquid chromatography and tandem mass spectrometry). Patients were classified by Multiple Sclerosis Severity Score (MSSS) to mild/moderate (MSSS, <6.7) and severe (MSSS, >6.7). RESULTS: Disease-modifying therapies are associated with increased TAS, decreased TOS, OSI, and 8-oxodG/creatinine. Regardless of therapy, women had a less favorable redox status (lower TAS, higher TOS and OSI). Patients with MSSS>6.7 and without DMTs had higher OSI than patients who received DMTs. Women with MSSS>6.7 without DMTs had lower TAS than women with DMTs, whereas in the same stage of MS, men without DMTs had higher TOS than patients with DMTs. Women with MSSS<6.7 and with DMTs had lower 8-oxodG/creatinine compared with those without DMT therapy. CONCLUSIONS: The antioxidant effects of DMTs were evidenced in this study. The gender-related effects of DMTs on the OS imply the personalized antioxidant pharmacotherapy, especially for the women. The OS biomarkers have a potential as the prognostic for the assessment of DMTs outcomes in patients with RRMS.

Indirect estimation of reference intervals for thyroid parameters using advia centaur XP analyzer.

Background: The aim of this study was to determine the reference intervals (RIs) for thyroid stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3) and FT3/FT4 ratio using indirect methods. Methods: We analyzed 1256 results TSH, FT4 and FT3 collected from a laboratory information system between 2017 and 2021. All measurements were performed on a Siemens ADVIA Centaur XP analyzer using the chemiluminescent immunoassay. We calculated the values of the 2.5th and 97.5th percentiles as recommended by the IFCC (CLSI C28-A3). Results: The RIs derived for TSH, FT4, FT3 and FT3/FT4 ratio were 0.34-4.10 mIU/L, 11.3-20.6 pmol/L, 3.5-6.32 pmol/L and 0.21-0.47, respectively. We found a significant difference between calculated RIs for the TSH and FT4 and those recommended by the manufacturer. Also, FT3 values were significantly higher in the group younger than 30 years relative to the fourth decade (5.26 vs. 5.02, p=0.005), the fifth decade (5.26 vs. 4.94, p=0.001), the sixth decade (5.26 vs. 4.87, p<0.001), the seventh decade (5.26 vs. 4.79, p<0.001) and the group older than 70 years old (5.26 vs. 4.55, p<0.001). Likewise, we found for TSH values and FT3/FT4 ratio a significant difference (p <0.001) between different age groups. Conclusions: The establishing RIs for the population of the Republic of Srpska were significantly differed from the recommended RIs by the manufacturer for TSH and FT4. Our results encourage other laboratories to develop their own RIs for thyroid parameters by applying CLSI recommendations.

Magnesium supplementation and iron status among female students: The intervention study.

Background: Literature data indicate the benefit of magnesium (Mg) supplementation. The aim of this study was to examine the effect of short-term Mg supplementation on iron status in healthy female participants. Methods: One hundred healthy female students of the University of Belgrade - Faculty of Pharmacy participated the study during eleven intervention days. Students ingested Mg preparations with the same dose of the active substance. The analysis included the measurement of serum iron, unsaturated iron binding capacity (UIBC), total iron binding capacity (TIBC), total Mg (tMg), ionized Mg (iMg), complete blood count, met-, carboxyand oxy-haemoglobin (metHgb, COHgb, O2Hgb). Transferrin concentrations and percentage of transferrin saturation (SAT) were calculated manually. The association among the analyzed biochemical parameters was examined using polynomial regression. A principal component analysis (PCA) was used for the evaluation of interdependence between the analyzed parameters. Results: A statistically significant trend for change in O2Hgb (%) by tertiles of iMg concentrations was found (P = 0.029). Serum tMg reached significant positive correlation with the SAT at concentration levels greater than 0.9 mmol/L, after 11 days of intervention (R2=0.116). Ionized Mg in a concentration higher than 0.6 mmol/L is positively correlated with SAT and serum Fe (R2=0.214; 0.199, respectively). PCA revealed variability of 64.7% for two axes after 11 days. Conclusions: Mg supplementation leads to an improvement in the certain iron status parameters even in individuals with optimal levels of these indices. However, caution should be exercised when supplementing Mg, and laboratory monitoring of the interaction is required.