Performance and comparability of laboratory methods for measuring ferritin concentrations in human serum or plasma: A systematic review and meta-analysis.

BACKGROUND: Different laboratory methods are used to quantify ferritin concentrations as a marker of iron status. A systematic review was undertaken to assess the accuracy and comparability of the most used methods for ferritin detection. METHODS AND FINDINGS: National and regional databases were searched for prospective, retrospective, sectional, longitudinal and case-control studies containing the characteristics and performance of at least one method for serum/plasma ferritin determinations in humans published to date. The analysis included the comparison between at least 2 methods detailing: sensitivity, precision, accuracy, predictive values, inter-methods adjustment, and use of international reference materials. Pooled method performance was analyzed for each method and across methods. OUTCOMES: Search strategy identified 11893 records. After de-duplication and screening 252 studies were assessed, including 187 studies in the qualitative analysis and 148 in the meta-analysis. The most used methods included radiometric, nonradiometric and agglutination assays. The overall within-run imprecision for the most reported ferritin methods was 6.2±3.4% (CI 5.69-6.70%; n = 171), between-run imprecision 8.9±8.7% (CI 7.44-10.35%; n = 136), and recovery rate 95.6% (CI 91.5-99.7%; n = 94). The pooled regression coefficient was 0.985 among all methods analyzed, and 0.984 when comparing nonradiometric and radiometric methods, without statistical differences in ferritin concentration ranging from 2.3 to 1454 µµg/L. CONCLUSION: The laboratory methods most used to determine ferritin concentrations have comparable accuracy and performance. Registered in PROSPERO CRD42016036222.

Reticulocyte hemoglobin content (MCHr) in the detection of iron deficiency.

BACKGROUND: Blood hemoglobin (Hb) concentration within the reference interval does not exclude iron deficiency (ID): individuals with normal stores lose iron during a long period before their Hb falls below of the level that is defined as anemia. The process entails a decrease of storage iron, shown by serum ferritin below reference range, followed by iron depletion, eventually leading to iron restricted erythropoiesis; consequence of an imbalance between erythropoietic iron requirements and too low supply is a reduction of Hb synthesis in reticulocytes. OBJECTIVE: We study the potential utility of mean reticulocyte hemoglobin content (MCHr), reported by CELL-DYN Sapphire (Abbott Diagnostics) analyzer, in the detection of ID in non-anemic adults. METHODS: 207 patients with Hb within the reference range were enrolled. ID was defined as Hb>120g/L (women), >130g/L (men) and serum ferritin <30µg/L. Student's t-test was applied to detect deviations between groups, statistical significance P<0.05. The performance of MCHr in detecting ID was evaluated applying Receiver Operating Characteristic (ROC) curve analysis. Kappa test was applied to verify concordance between ferritin and MCHr. RESULTS: 68 patients (33%) suffered ID, median MCHr in this group was 26.9 pg, statistically different from the normal group, MCHr 30.9pg (P<0.0001). ROC ANALYSIS (GOLD STANDARD FERRITIN <30µG/L): Area under curve AUC 0.851 (95% CI 0.770-0.912) at cut off 30.0 pg, with sensitivity 84.1% and specificity 71.1%. Kappa 0.667 (95% CI 0.527-0.858). CONCLUSION: Due to their short lifespan reticulocytes and derived parameters reflect current erythropoiesis status, before Hb and erythrocyte indices drop. MCHr had the best AUC and diagnostic value compared to erythrocyte indices. MCHr is a reliable test for the investigation of ID and could improve the detection of iron deficient adults.

Percepción del ambiente educacional en dos escuelas de medicina con currículo tradicional: Estudio longitudinal / Longitudinal perception of the educational environment in two medical schools with traditional curricula in Chile and Spain

Background: To establish an educational environment that ensures the quality of the teaching-learning process is a challenge for any educational institution. The questionnaire DREEM (Dundee Ready Educational Environment Measure) is used to identify strengths and weaknesses of an educational environment and to compare different medical schools. Aim: To evaluate the changes in the perception of educational environment by students of the Schools of Medicine of the University of Zaragoza, UZar (Spain) and the University of Chile, UCh (Chile) at two points in their curricula. Material and Methods: DREEM questionnaire was answered by 90 students from the UZar and 87 students of the UCh, when they were in the first year (2009) and in the fourth year of their career (2012). Results: At both universities the overall mean scores of DREAM were significantly higher in students in their first year than those obtained in the fourth year (137.5/118.3 for UZar and 128.6/118.8 for UCh). Items with worse perception in the fourth year were observed in subscales Learning Perception and Atmosphere Perception. Items with good evaluation (≥ 3.0) were the subscales Perception of teachers, academic self-perception, perception of Environment and Social Self-perception. Conclusions: The perception of Chilean and Spanish students about their educational environments indicates that the stage of their medical training is more important than the geographical context or educational institution.

Clinical Value of Hypochromia Markers in the Detection of Latent Iron Deficiency in Nonanemic Premenopausal Women.

BACKGROUND: Iron deficiency (ID) is the most common cause of anemia in fertile women and hemoglobin (Hb) within the reference interval does not exclude ID. The consequence of an imbalance between the iron requirements and supply is a reduction of red-cell Hb content, which causes hypochromic cells. The aim of this study was to assess the reliability of new parameters low Hb density (LHD%), reticulocyte Hb equivalent (RetHe), and percentage of hypochromic erythrocytes (%HypoHe) in the detection of latent ID (LID), defined as depletion of iron stores without anemia. METHODS: Two hundred fifty consecutive nonanemic women in fertile age (18-40 years, mean 33.5 years), whose analyses had been requested by general practitioners, were included. Independent samples t-test, receiver operating characteristic (ROC) curve analysis (gold standard for detecting LID ferritin <30 µg/l), and Cohen's kappa index were applied. RESULTS: One hundred fifty-three women had ferritin within the reference range and Hb >120 g/L; 97 (38.8%) had LID. The results were as follows: %HypoHe-AUC 0.934, cutoff 1.6%, sensitivity 85.7%, specificity 92.1%; RetHe-AUC 0.914, cutoff 29.9 pg, sensitivity 86.8%, specificity 85.7%; LHD%-AUC 0.898, cutoff 5.0%, sensitivity 85.9%, specificity 84.1%. Applying those cutoffs, agreement between ferritin and %HypoHe was κ 0.61 and 0.56 for RetHe and LHD%. CONCLUSIONS: LHD%, %HypoHe, and RetHe emerge as reliable tests for the investigation of LID and could improve the ability to detect ID before anemia is present.

Correlation Analysis of Exercise-Induced Changes in Plasma Trace Element and Hormone Levels During Incremental Exercise in Well-Trained Athletes.

This study analyzes the relationship between hormonal changes induced by exercise and variations in trace elements associated with oxidative stress during incremental exercise. Nineteen well-trained endurance athletes performed a cycle ergometer test: after a warm-up of 10 min at 2.0 W kg(-1), workload increased by 0.5 W kg(-1) every 10 min until exhaustion. The analysis was controlled for prior diet and activity patterns, levels of exercise training, and time of day (circadian rhythms). Whole blood lactate concentration and plasma concentrations of ions (Zn, Se, Mn, and Co), insulin, glucagon, aldosterone, thyroid stimulating hormone (TSH), calcitonin, and parathyroid hormone (PTH) were measured at rest; at the end of each stage; and 3, 5, and 7 min post-exercise. The statistical analysis involved paired non-parametric tests and correlation coefficients. No significant differences were found in Mn or Co levels as a function of exercise intensity. Zn and Se levels at the end of the exercise protocol and over the recovery time were significantly different to baseline. Further, Zn levels were significantly correlated with aldosterone, calcitonin, and PTH levels, while Se levels were associated with aldosterone, calcitonin, and TSH levels. Our results indicate several different patterns of association between acute changes in hormone concentrations and variations in trace element concentrations related to oxidative stress during submaximal exercise.

[Longitudinal perception of the educational environment in two medical schools with traditional curricula in Chile and Spain]. / Percepción del ambiente educacional en dos escuelas de medicina con currículo tradicional: Estudio longitudinal.

BACKGROUND: To establish an educational environment that ensures the quality of the teaching-learning process is a challenge for any educational institution. The questionnaire DREEM (Dundee Ready Educational Environment Measure) is used to identify strengths and weaknesses of an educational environment and to compare different medical schools. AIM: To evaluate the changes in the perception of educational environment by students of the Schools of Medicine of the University of Zaragoza, UZar (Spain) and the University of Chile, UCh (Chile) at two points in their curricula. MATERIAL AND METHODS: DREEM questionnaire was answered by 90 students from the UZar and 87 students of the UCh, when they were in the first year (2009) and in the fourth year of their career (2012). RESULTS: At both universities the overall mean scores of DREAM were significantly higher in students in their first year than those obtained in the fourth year (137.5/118.3 for UZar and 128.6/118.8 for UCh). Items with worse perception in the fourth year were observed in subscales Learning Perception and Atmosphere Perception. Items with good evaluation (≥ 3.0) were the subscales Perception of teachers, academic self-perception, perception of Environment and Social Self-perception. CONCLUSIONS: The perception of Chilean and Spanish students about their educational environments indicates that the stage of their medical training is more important than the geographical context or educational institution.

Variants of the Solute Carrier SLC16A1 Gene (MCT1) Associated With Metabolic Responses During a Long-Graded Test in Road Cyclists.

Variants of the solute carrier SLC16A1 gene have been associated with alterations in MCT1 expression, because of a lactate (La) transport deficiency across the cell membrane and a blood La accumulation. The aim of this study was to associate the allelic and genotypic frequencies of 1470T>A, 2917(1414) C>T, and IVS3-17A>C variants relative to the blood La kinetics and metabolic responses to a progressive effort until exhaustion. Twenty-five well-trained road cyclists performed a long-graded laboratory test: 10 minutes at 2.0 W·kg, first step at 2.5 W·kg with increments of 0.5 W·kg every 10 minutes until exhaustion. Blood La, nonesterified fatty acids (NEFAS), and glucose levels were measured; fat and carbohydrate oxidation rates were estimated through stoichiometric equations. Three variants of SLC16A1 gene were determined for each subject, which were divided in two groups: wt (wild type)/mt (mutated type) and mt/mt genotype group versus wt/wt genotype group. Metabolic responses were compared between both groups with an unpaired Student's t-test; Friedman and Wilcoxon tests were performed for nonparametric data. The statistical significance was set at p ≤ 0.05. For 1470TA polymorphism, no significant blood La differences were found between groups. 2197(1414)C>T allele carriers and IVS3-17A>C carriers showed significantly higher blood La levels, lower blood NEFAS, and glucose levels at submaximal intensities. These findings open a new perspective to investigate SLC16A1 variants (1470TA and IVS3-17A>C) on La deficiency transport and its regulation/interaction with other metabolic pathways. Future studies would be needed to clarify whether 1470T>A, 2917(1414)C>T, and IVS3-17A>C allelic/genotypic distribution benefit performance in endurance athletes.

Plasma levels of trace elements and exercise induced stress hormones in well-trained athletes.

This study analyzed the variation and relationship of several trace elements, metabolic substrates and stress hormones activated by exercise during incremental exercise. Seventeen well-trained endurance athletes performed a cycle ergometer test: after a warm-up of 10 min at 2.0 W kg(-1), the workload was increased by 0.5 W kg(-1) every 10 min until exhaustion. Prior diet, activity patterns, and levels of exercise training were controlled, and tests timed to minimize variations due to the circadian rhythm. Oxygen uptake, blood lactate concentration, plasma ions (Zn, Se, Mn and Co), serum glucose, non-esterified fatty acids (NEFAs) and several hormones were measured at rest, at the end of each stage and 3, 5 and 7 min post-exercise. Urine specific gravity was measured before and after the test, and participants drank water ad libitum. Significant differences were found in plasma Zn and Se levels as a function of exercise intensity. Zn was significantly correlated with epinephrine, norepinephrine and cortisol (r = 0.884, P < 0.01; r = 0.871, P < 0.01; and r = 0.808, P = 0.05); and Se showed significant positive correlations whit epinephrine and cortisol (r = 0.743, P < 0.05; and r = 0.776, P < 0.05). Neither Zn nor Se levels were associated with insulin or glucagon, and neither Mn nor Co levels were associated with any of the hormones or substrate metabolites studied. Further, while Zn levels were found to be associated only with lactate, plasma Se was significantly correlated with lactate and glucose (respectively for Zn: r = 0.891, P < 0.01; and for Se: r = 0.743, P < 0.05; r = 0.831, P < 0.05). In conclusion, our data suggest that there is a positive correlation between the increases in plasma Zn or Se and stress hormones variations induced by exercise along different submaximal intensities in well-hydrated well-trained endurance athletes.

Effect of sulphurous mineral water in haematological and biochemical markers of muscle damage after an endurance exercise in well-trained athletes.

To investigate the effects of sulphurous mineral water (SMW) after a hydroponic treatment on muscle damage, antioxidant activity and peripheral blood changes induced by submaximal exercise. Thirty well-trained male triathletes were supplemented with SMW or placebo: 3 weeks of placebo, 30 days of wash out and 3 weeks of SMW. After both periods, participants ran for 2 h at 70% maximal aerobic speed. Antioxidant enzymes, lipid peroxidation, antioxidant capacity and blood cell markers were compared between placebo and SMW at pre-exercise (T0), immediately post-exercise (T1), 24 h post-exercise (T2) and 48 h post-exercise (T3). Total thiols decreased until T3 vs. T0 for both placebo and SMW; transient red blood cells, haemoglobin and haematocrit increased were shown at T1 vs. T0 and for leucocytes until T2 vs. T0, only for placebo group. Total thiols increased significantly in SMW vs. placebo at T0; Thiobarbituric acid reactive species was significantly higher at T0, T1, T2 and T3; catalase increased significantly at T1; creatine phosphokinase decreased significantly at T1, T2 and T3, although no significant differences were found at T0. Furthermore, red blood cells, haemoglobin and haematocrit were significantly higher and leucocytes were significantly lower at T0 and T1 in SMW group vs. placebo group. This study suggests that three weeks of SMW supplementation may protect from exercise-induced muscle damage.

Biomarkers of hypochromia: the contemporary assessment of iron status and erythropoiesis.

Iron status is the result of the balance between the rate of erythropoiesis and the amount of the iron stores. Direct consequence of an imbalance between the erythroid marrow iron requirements and the actual supply is a reduction of red cell hemoglobin content, which causes hypochromic mature red cells and reticulocytes. The diagnosis of iron deficiency is particularly challenging in patients with acute or chronic inflammatory conditions because most of the biochemical markers for iron metabolism (serum ferritin and transferrin ) are affected by acute phase reaction. For these reasons, interest has been generated in the use of erythrocyte and reticulocyte parameters, available on the modern hematology analyzers. Reported during blood analysis routinely performed on the instrument, these parameters can assist in early detection of clinical conditions (iron deficiency, absolute, or functional; ineffective erythropoiesis, including iron restricted or thalassemia), without additional cost. Technological progress has meant that in recent years modern analyzers report new parameters that provide further information from the traditional count. Nevertheless these new parameters are exclusive of each manufacturer, and they are patented. This is an update of these new laboratory test biomarkers of hypochromia reported by different manufactures, their meaning, and clinical utility on daily practice.

Erythrocyte and reticulocyte parameters in iron deficiency and thalassemia.

INTRODUCTION: Red blood cells (RBCs) extended parameters or erythrocyte subsets are now reported by the new Sysmex XE 5000 analyzer. This study was aimed at establishing a characteristic analytical feature, including the new erythrocyte and reticulocyte parameters, in case of thalassemia trait and iron deficiency (IDA). METHODS: Ninety healthy individuals, 136 ß-thalassemia carriers, 121 mild IDA, and 126 severe IDA patients were analyzed. RESULTS: The values obtained for the RBC extended parameters were significantly different (P<0.0001) in the groups; the only exception was %Hypo-He in the case of mild IDA and thalassemia (P=0.6226). %Hypo-He was considerably greater in severe IDA (23.4%) than in mild cases (12.4%), P<0.0001. %MicroR was more increased in thalassemia (38.6 %) than in the mild IDA (16.5%, P<0.001) and in severe IDA (21.6%, P<0.001). Immature reticulocyte fraction (IRF) mean values in the groups were statistically different; the thalassemia group had an intermediate value (8.7%) between healthy (4.4%) and IDA (16.7 and 12.9%). CONCLUSIONS: Erythrocytosis and severe microcytosis, together with a high percentage of microcytes and a moderate increase in IRF, is the profile of ß-thalassemia carriers, whereas anisocytosis and the hypochromic subset correlates with the severity of the anemia in iron-deficient patients.

Submaximal exercise intensities do not provoke variations in plasma magnesium concentration in well-trained euhydrated endurance athletes with no magnesium deficiency.

The purpose of this study was to assess the effect of exercise intensity during an incremental exercise test on plasma Mg concentration in well-trained euhydrated athletes. Twenty-seven well-trained endurance athletes carried out a cycloergometer test: after a warm-up of 10 min at 2.0 W·kg(-1), the workload increased by 0.5 W·kg(-1) every 10 min until exhaustion. Oxygen uptake (VO(2)), blood lactate concentration ([La(-)](b)), catecholamines, and plasma Mg were measured at rest, at the end of each stage and at 3, 5 and 7 minutes post-exercise. Urine specific gravity (U(SG)) was analyzed before and after the test, and subjects drank water ad libitum. Fat oxidation rate (FAT(oxr)), carbohydrate oxidation rate (CHO(oxr)), energy expenditure from fat (EE(FAT)), energy expenditure from carbohydrate (EE(CHO)), and total EE (EE(TOTAL)) were estimated using stoichiometric equations. Plasma Mg concentration at each relative exercise intensity (W·kg(-1)) were compared by means of repeated-measures ANOVA. Pearson's correlations were performed to assess the relationship between variables. The significance level was set at p<0.05. No significant differences were found in U(SG) between before and after the test (1.014±0.004 vs 1.014±0.004 g·cm(-3)). Nor were significant differences found in plasma Mg as a function of the different exercise intensities. Further, no significant correlations were detected between Mg and metabolic variables. In conclusion, acute exercise at a range of submaximal intensities in euhydrated well-trained endurance athletes does not affect plasma Mg concentration, suggesting that the plasma volume plays an important role in Mg homeostasis during exercise.

The role of automated measurement of RBC subpopulations in differential diagnosis of microcytic anemia and ß-thalassemia screening.

Cell counter-based formulas have been used in the differential diagnosis of microcytic anemia. The measurement of RBC subpopulations is now available on the Sysmex XE 5000 analyzer (Sysmex, Kobe, Japan). We describe the new formulas: % microcytic - % hypochromic; and % microcytic - % hypochromic - red cell distribution width (RDW), derived from the percentages of microcytic and hypochromic RBCs. The present study aimed to prospectively evaluate the reliability of these new formulas in the differential diagnosis of microcytosis and ß-thalassemia screening compared with already published indices. The indices were calculated for a set of 250 iron-deficient patients and 270 ß-thalassemia carriers. Independent samples t test and receiver-operating characteristics analysis were applied. The % microcytic - % hypochromic - RDW, % microcytic - % hypochromic, and Green and King indices provided higher areas under the curve. The % microcytic - % hypochromic - RDW was the most reliable index evaluated, with 100% sensitivity and 92.6% specificity. This index can be used to efficiently screen patients with microcytosis for further hematologic studies to confirm ß-thalassemia.

Oral iron treatment has a positive effect on iron metabolism in elite soccer players.

The purpose of this study was to assess the effects of oral iron supplementation on hematological and iron metabolism in elite soccer players. Thirty-five members of the Real Zaragoza SAD soccer team took part in this study: group A (GA, n = 24; Spanish Premier League) took an oral iron supplement of 80 mg day(-1) for 3 weeks, and group B (GB, n = 11; Spanish Third Division League) did not receive any supplementation. In GA, the parameters were measured before and after giving the iron supplements, while in GB, measurements were only made at the time of collecting the second set of data from GA. After supplementation, GA showed an increase in serum iron (SI) (P < 0.05), serum ferritin (Ftn) (P < 0.01), and transferrin saturation (Sat) (P < 0.01) with respect to the basal values. In addition, GA showed higher values of hematocrit (P < 0.01), mean corpuscular volume (P < 0.01), Ftn (P < 0.01), and Sat (P < 0.01) than GB. No significant differences were found in any other parameters. More specifically, a higher percentage of players had Ftn levels above upper limits in GA vs. GB (P < 0.05), and GB had a higher incidence of Ftn below lower limits with respect to subjects in GA (P < 0.01). Further, after treatment, 58.3% of GA had >800 mg of SI, while all players in GB presented levels below the lower limits. In conclusion, iron supplementation with 80 mg·day(-1) for 3 weeks, before the start of the soccer season, can be recommended for elite soccer players.

Percentage of hypochromic erythrocytes as a potential marker of iron availability.

BACKGROUND: The percentage of hypochromic red cells (% Hypo-He) is now available on the Sysmex analyzer XE 5000 (Sysmex Corporation, Kobe, Japan). In this study the reliability of % Hypo-He in the assessment of iron status in the presence of inflammation is investigated. METHODS: Ninety healthy subjects, 91 patients with iron deficiency anemia (IDA) previous to therapy, 65 patients with chronic kidney disease (CKD), 57 patients with anemia of chronic diseases (ACD) and 28 patients with storage iron deficiency (ACD/IDA) receiving therapy were analyzed. Pearson's correlation, Independent samples t-test, receiver operating characteristic (ROC) curve analysis and Cohen's k index were applied. RESULTS: % Hypo-He values inversely correlated with the blood hemoglobin (Hb) (r=-0.78) and Hb content (MHC, r=-0.75). In patients with IDA and ACD/IDA the values obtained for % Hypo-He showed no statistical difference (p=0.5037). ROC analysis results for % Hypo-He in the detection of iron deficiency defined by a serum transferrin receptor (sTfR) >21 nmol/L. The area under the curve is 0.929; cut-off 3.6%, sensitivity 91.5% and specificity 80.9%. Using the threshold 3.6% the k index obtained in comparison to sTfR was 0.64. CONCLUSIONS: % Hypo-He is a reliable parameter for the detection of iron deficiency in patients with anemia in the presence of inflammation.

Plasma trace elements levels are not altered by submaximal exercise intensities in well-trained endurance euhydrated athletes.

The purpose of this study was to assess the effect of relative exercise intensity on various plasma trace elements in euhydrated endurance athletes. Twenty-seven well-trained endurance athletes performed a cycloergometer test: after a warm-up of 10 min at 2.0 W kg⁻¹, workload increased by 0.5 W kg⁻¹ every 10 min until exhaustion. Oxygen uptake, blood lactate concentration ([La⁻](b)), and plasma ions (Zn, Se, Mn and Co) were measured at rest, at the end of each stage, and 3, 5 and 7 min post-exercise. Urine specific gravity (U(SG)) was measured before and after the test, and subjects drank water ad libitum. Fat oxidation (FAT(OXR)), carbohydrate oxidation (CHO(OXR)), energy expenditure from fat (EE(FAT)), from carbohydrates (EE(CHO)) and total EE (EE(T)) were estimated using stoichiometric equations. A repeated measure (ANOVA) was used to compare plasma ion levels at each exercise intensity level. The significance level was set at P<0.05. No significant differences were found in U(SG) between, before, and after the test (1.014±0.004 vs. 1.014±0.004 g cm⁻³) or in any plasma ion level as a function of intensity. There were weak significant correlations of Zn (r=0.332, P<0.001) and Se (r=0.242, P<0.01) with [La⁻](b), but no relationships were established between [La⁻](b), VO2, FAT(OXR), CHO(OXR), EE(FAT), EE(CHO), or EE(T) and plasma ion levels. Acute exercise at different submaximal intensities in euhydrated well-trained endurance athletes does not provoke a change in plasma trace element levels, suggesting that plasma volume plays an important role in the homeostasis of these elements during exercise.

Learning styles favoured by professional, amateur, and recreational athletes in different sports.

The aim of this study was to characterize the learning styles of different groups of athletes grouped according to level of performance and sport. Seventy-one male athletes completed a questionnaire on learning styles at the beginning of the 2008-2009 training season. Learning styles were assessed using the Honey-Alonso Learning Styles Questionnaire, and were also converted into learning styles described by Kolb. The Honey-Alonso learning styles were compared among the various groups using one-way analysis of variance, and the Kolb learning styles that were most favoured using a chi-square test. Pearson's correlation coefficient was used to verify the relationships between variables. No significant differences were observed in learning styles between different sports and physical activities. Years of experience did not correlate strongly with learning styles. With respect to level of performance, the pragmatic component was significantly lower in professional athletes than amateur and recreational athletes. These characteristics of learning styles preferred by the athletes should help coaches and physical trainers to reflect on their role as educators in the context of planning sports training.

Erythrocyte and Reticulocyte Indices on the LH 750 as Potential Markers of Functional Iron Deficiency.

Reticulocyte hemoglobin content (CHr) and percentage of hypochromic cells (%Hypo) are restricted to the Siemens analysers. The aims of the study were to investigate the correlation of Red cells size factor (RSf) and low Hemoglobin density (LHD%), reported by Beckman-Coulter analysers, with CHr and %Hypo in the assessment of iron status in the presence of inflammation. 381 samples were run on both LH 750 (Beckman-Coulter) and Advia 2120 (Siemens) analysers. Correlation between parameters were calculated and the diagnostic performance of the new parameters was assessed. Results. Correlation between RSf and CHr, r = 0.85. ROC curve analysis for RSf in the diagnosis of iron restricted erythropoiesis defined as CHr < 28 pg: AUC 0.983; Cutoff 91.1%; Sensitivity 98.8%; Specificity 89.6% Correlation between LHD% and %Hypo, r = 0.869. ROC curve analysis for LHD% in the diagnosis of iron deficiency defined by %Hypo >5%: AUC 0.954; Cut off 6.0%; Sensitivity 96.6%; Specificity 83.2% Conclusions. RSf and LHD% could be reliable parameters for the study of iron metabolism status.

Potential utility of the new Sysmex XE 5000 red blood cell extended parameters in the study of disorders of iron metabolism.

BACKGROUND: New erythrocyte parameters are reported by the Sysmex XE 5000 analyzer. This instrument measures the hemoglobin (Hb) content of individual red cells, calculates the percentage of hypochromic red cells (%Hypo He) and the percentage of hyperchromic red cells (%Hyper He) and quantifies the proportion of marginally sized erythrocytes (%Micro R and %Macro R). The goals of the study were to establish the reference range for erythrocyte extended parameters, their value in different types of anemia and to investigate their reliability in the study of disorders of iron metabolism. MATERIALS: Three hundred and ninety samples were analyzed. The Kolmogorov-Smirnoff test, independent samples t-test and Pearson correlation were calculated; receiver operating characteristic (ROC) curve analysis was used to determine their diagnostic performance. RESULTS: The values of the four parameters studied were normally distributed and statistically different (p<0.0001) in the different groups of patients; the only exception was %Hypo He in cases of iron deficiency and thalassemia (p=0.3758). Results of ROC curve analysis for %Hypo He in the diagnosis of restricted erythropoiesis reticulocyte Hb content (reticulocyte hemoglobin content, Ret He <29 pg) were: area under the curve 0.963; cut-off 1.8%; sensitivity 98.3%; specificity 91.1%. CONCLUSIONS: The new parameters appear to be sensitive for detecting small changes in the number of red cells with inadequate hemoglobinization and volume.

Comparison of different theoretical models estimating peak power output and maximal oxygen uptake in trained and elite triathletes and endurance cyclists in the velodrome.

The aim of this study was to assess which of the equations that estimate peak power output and maximal oxygen uptake (VO2max) in the velodrome adapt best to the measurements made by reference systems. Thirty-four endurance cyclists and triathletes performed one incremental test in the laboratory and two tests in the velodrome. Maximal oxygen uptake and peak power output were measured with an indirect calorimetry system in the laboratory and with the SRM training system in the velodrome. The peak power output and VO2max of the field test were estimated by means of different equations. The agreement between the estimated and the reference values was assessed with the Bland-Altman method. The equation of Olds et al. (1995) showed the best agreement with respect to the peak power output reference values, and that of McCole et al. (1990) was the only equation to show good agreement with respect to the VO2max reference values. The VO2max values showed a higher coefficient of determination with respect to maximal aerobic speed when they were expressed in relative terms. In conclusion, the equations of Olds et al. (1995) and McCole et al. (1990) were best at estimating peak power output and VO2max in the velodrome, respectively.