Total Iron Binding Capacity Concentration Research Articles

Comparison of Hemopoietic Biochemical Parameters in the First, Second, and Third Trimester of Pregnant Females Attending a Tertiary Care Hospital of Western Rajasthan.

Pregnant women constitute a high-risk group for nutrient deficiency anemia which may be associated with detrimental effects on maternal and infant health. This study aimed to assess and compare hematological and biochemical changes across trimesters in pregnant women, considering parameters such as hemoglobin, serum iron, unsaturated iron-binding capacity (UIBC), total iron-binding capacity (TIBC), ferritin, vitamin B12, and folic acid. The research sought to identify mean value differences, correlations, and potential implications for maternal healthcare practices. A hospital-based prospective observational study was conducted, involving 60 primigravida women with singleton pregnancies. The subjects were assessed during the first, second, and third trimesters. Biochemical parameters were assessed using standard methods, and statistical analysis was performed to identify significance and correlations. The study revealed a significant decline in hemoglobin, serum iron, ferritin, vitamin B12, and folic acid as pregnancy advanced. Hemoglobin levels decreased from 11.40 g/dl (first trimester) to 10.43 g/dl (third trimester). Serum iron exhibited a decline from 109.73 µg/dl (first trimester) to 94.03 µg/dl (third trimester). Serum ferritin decreased from 24.93 ng/ml (first trimester) to 18.21 ng/ml (third trimester). Vitamin B12 levels dropped from 255.92 pg/ml (first trimester) to 92.13 pg/ml (third trimester). Folic acid levels decreased from 13.82 ng/ml (first trimester) to 11.77 ng/ml (third trimester). UIBC and TIBC concentrations increased progressively across trimesters. Statistical evaluations confirmed the significance of these trends. The coefficient of correlation indicated positive relationships between hemoglobinand serum iron, ferritin, folic acid, and vitamin B12.Positive correlation between serum iron and ferritin, vitamin B12, and negative with folic acid. Serum ferritin negatively correlated with vitamin B12 and folic acid. Serum folic acid and vitamin B12 are positively correlated. The findings emphasize the dynamic nature of hematological and biochemical changes during pregnancy. The observed trends have profound implications for maternal healthcare practices, urging targeted interventions, early monitoring, and supportive supplementation. Recognizing these variations contributes to the optimization of health outcomes for both mother and child.

High Ferritin and Low Total Iron-Binding Capacity in Plasma Predict All-Cause Mortality During the First 3 Years of Hemodialysis in Patients with End-Stage Chronic Kidney Disease.

To determine all-cause mortality rate and the predictive value of plasma ferritin and total iron-binding capacity (TIBC) concentrations for mortality during the first 3 years of hemodialysis in patients with end-stage chronic renal disease (ESRD). We conducted a study on 174 ESRD patients (estimated Glomerular Filtration Rate < 15 mL/min/1.73m2). The plasma TIBC level was quantified by the ELISA method in all patients at the time before hemodialysis. Based on TIBC concentration, patients were divided equally into 2 groups. Each group had 87 patients. Patients were initiated on hemodialysis, and patients who died from any cause during the first 3 years of hemodialysis were recorded. The all-cause mortality rate of ESRD patients in the first 3 years of maintenance hemodialysis was 22.9%. Plasma high hs-CRP, high ferritin, and low TIBC concentrations were independent factors associated with all-cause mortality in the patients. Plasma ferritin (cut-off value = 454.2 ng/L) and TIBC (cut-off value = 39.84 µmol/L) were predictors of all-cause mortality, AUC is: 0.772; 0.723, p < 0.001. Plasma ferritin and TIBC were good predictors of all-cause mortality in ESRD patients during the first 3 years of hemodialysis.

Study of some biochemical and hematological parameters in continuously hemodialysis patients in Kirkuk city

Introduction: The severity of chronic renal failure (CRF) classified by professional guidelines in five stages, stage 5 is a severe illness often called end stage kidney failure or end stage renal disease (ESRD), dialysis may be used for this stage. Dialysis treatments replace some of these functions through diffusion (waste removal) and ultrafiltration (fluid removal). Hemodialysis, is a process of purifying the blood, when the kidneys are not working normally. It is one of three renal replacement therapies (the other two being peritoneal dialysis and renal transplant).&#x0D; Materials and Methods: The samples of this study consists of 80 patients (42 males, 38 females) and 85 healthy individuals (43 males, 42 females) from (20 - 70) years old of age. Serum paraoxonase-1 (PON1), `5-nucleatidase, blood urea ( BU), serum creatinine Cr, serum iron (Fe), serum total iron binding capacity (TIBC), Serum feritin, serum amylase activity and serum lipase activity were determined. Some hematological parameters includes packed cell volume (PCV), hemoglobin (Hb), white blood cells count (WBCs), red blood cell count (RBCs) were measured, the erythrocyte sedimentation rate (ESR), Body mass index (BMI) and creatinine clearance Ccl were also measured.&#x0D; Results: Decreased levels of some enzymes activity and some biochemical and hematological parameters and increased others in continuous and regular hemodialysis patients in Kirkuk city. Blood urea and serum creatinine showed significant increased (P˂0.05) in their levels, while the creatinine clearance was significantly decreased (P˂0.05) in patients with continuous hemodialysis patients when compared to those of controls. In the present study; there was significant decreased (P˂0.05) in PON-1 in patients when compared to those of controls. However, the serum`5-NT, amylase and lipase activities were significantly increased (P ˂ 0.05) in these patients when compared with serum of normal individuals. In the present study; there was significant decreased in Fe and TIBC concentrations in the serum of patients when compared to those of healthy control individuals (P˂0.05). While the serum ferritin was significantly increased (P˂0.05) in these patients as compared to the controls. In the present study; there was significant decreased (P ˂ 0.05) in Hb and PCV and RBCs concentrations inthese patients when compared to those of controls. While WBCs and ESR was significantly increased (P˂0.05) in these patients as compared to the controls.&#x0D; Conclusion: Serum paraoxonase PON -1 activity is the most commonly affected than other biochemical parameters in continuous hemodialysis patients. Anemia, pancreatitis are the common and often an early complication of chronic renal diseases

Characteristics of systemic inflammation and brain iron deposition in Parkinson's disease patients.

ObjectiveThis study aimed at determining the characteristics of systemic inflammation and brain iron deposition in Parkinson's disease (PD) patients.MethodsThirty two PD patients and 30 gender‐ as well as age‐matched controls were enrolled. Serum interleukin (IL)‐1β, IL‐33, tumor necrosis factor (TNF)‐α, IL‐6, IL‐10, ferritin, iron, and total iron binding capacity (TIBC) levels were assayed. Quantitative susceptibility mapping (QSM) was used to quantitatively analyze brain iron accumulation in the regions of interest (ROIs). Correlations between concentrations of inflammatory cytokines and biomarkers for peripheral iron metabolism, brain iron deposition were evaluated in the PD group.ResultsSerum concentrations of IL‐1β and IL‐33 were found to be significantly elevated in the PD group compared to the control group, and in early‐stage PD group compared to advanced‐stage PD group. Total QSM value for bilateral ROIs was significantly elevated in the PD group compared to the control group, and in advanced‐stage PD group compared to early‐stage PD group. There was a significant inverse correlation between serum IL‐1β concentration and total QSM value for bilateral ROIs, between serum ferritin, iron, TIBC concentrations, and total QSM value for bilateral ROIs in PD patients. However, there was no significant correlation between serum IL‐1β concentrations and serum ferritin, iron, TIBC concentrations in PD patients.InterpretationThe inflammatory state and chronic brain iron deposition progression in PD patients might be asynchronous. Alterations in systemic inflammation were not correlated with peripheral iron metabolism and might not contribute to the aggravation of brain iron deposition in PD patients.

Plasma Iron Indices in Pregnant Women Referred to the University of Abuja Teaching Hospital, Nigeria

Background and Aims: Iron Deficiency (ID) is a common obstetric problem and nutritional disorder that occurs mostly in developing countries. Hence, nutritional studies are required every few years to determine the necessary healthcare interventions for pregnant women. This cross-sectional study evaluated the plasma iron, ferritin, transferrin, total iron-binding capacity (TIBC), and unsaturated iron-binding capacity (UIBC) levels of pregnant women referred to the University of Abuja Teaching Hospital, Gwagwalada, Abuja, Nigeria. Materials and Methods: Blood samples were collected from 58 non-pregnant women, 22 pregnant women in the first trimester, 52 in second, and 44 in the third trimester. The plasma ferritin concentration of these samples was measured by chemiluminescence assay, while the plasma transferrin, TIBC, and iron concentrations were measured by enzyme-linked immunosorbent assay. Plasma ferritin levels &lt;15μg/L were considered ID. Results: The overall prevalence of ID in pregnant women was 33.1%. However, the prevalence of ID was 29.3%, 22.7%, 34.6%, and 36.4% among non-pregnant women, women in the first trimester, second and third trimester, respectively. The mean±SEM iron levels were significantly higher among pregnant women compared to non-pregnant women (p=0.004). There was no significant difference in the mean±SEM of plasma ferritin, transferrin and TIBC concentrations between pregnant and non-pregnant women (p&gt;0.05). Nevertheless, the mean±SEM plasma iron, ferritin, and UIBC significantly differed across the gestational ages of pregnant women (p&lt;0.05). Conclusions: This study revealed a high prevalence of ID during pregnancy, which increases with the trimester of affected women. Healthcare interventional measures that can address ID are recommended.

Time course of serum cobalamin, folate, and total iron binding capacity concentrations in pregnant bitches and association with hematological variables and survival.

BackgroundHypocobalaminemia, hypofolatemia and iron deficiency are associated with pregnancy‐related anemia (PRA) and neonatal survival (NS) in women. Similar associations have not been investigated in pregnant bitches.ObjectivesTo investigate time course and associations of serum cobalamin, folate and iron status indicators with hematological variables and NS in pregnant bitches.AnimalsForty‐eight pregnant bitches.MethodsA prospective cohort study. Pregnancy was confirmed by abdominal ultrasonography twice during mid‐ and late pregnancy, concurrently with blood sampling. Associations among pregnancy stage, NS and laboratory variables were assessed by generalized estimating equations.ResultsCompared with midpregnancy, serum cobalamin (adjusted mean [95% confidence interval, CI]) decreased at late pregnancy (430 pg/mL [394‐466] versus 330 pg/mL [303‐357], respectively; P < .001), whereas serum folate did not. Every increment of 1 in parity number or litter size corresponded to 28.6 pg/mL (95% CI, 5.6‐51.6; P = .02) and 20.3 pg/mL (95% CI, 10.9‐29.7; P < .001) decrease in serum cobalamin concentration. Compared with midpregnancy, serum iron (P < .001) and transferrin saturation (P = .01) increased at late pregnancy. The decrease in red blood cell count (P < .001) at late pregnancy was significantly, albeit weakly, correlated with decreasing serum folate concentration (r = 0.33; P = .02). None of the measures was associated with NS.Conclusions and Clinical SignificancePregnancy‐related anemia was common at late pregnancy. Unlike in women, in pregnant bitches, serum iron and transferrin saturation were increased at late pregnancy. Future studies are warranted to investigate the clinical ramifications of hypocobalaminemia in pregnant bitches and the utility of prophylactic folate administration in mitigating PRA.

Iron Profile and Glycaemic Control in Patients with Type 2 Diabetes Mellitus

Iron overload is increasingly being connected to insulin resistance in Type 2 Diabetes Mellitus (T2DM) patients. Free iron causes the assembly of reactive oxygen species that invariably steer the body’s homeostasis towards oxidative stress-mediated diabetic complications. This study aims to assess the serum iron, total iron binding capacity (TIBC), and percentage transferrin saturation (Tsat) of 150 subjects divided into three groups (I,II,III) of 50. Healthy individuals (controls) constituted Group I. Group II consisted of T2DM patients with optimal glycaemic control. T2DM patients with suboptimal glycaemic control formed group III. Mean serum free iron concentration was 105.34 ± 3.5, 107.33 ± 3.45, and 125.58 ± 3.45 μg/dL in Group I, Group II, and Group III, respectively. Mean serum TIBC concentration in Group I, Group II, and Group III was 311.39 ± 5.47, 309.63 ± 6.1, and 284.2 ± 3.18μg/dL, respectively. Mean serum transferrin saturation (%) in Group I, Group II, and Group III was 34.17 ± 1.21, 35.02 ± 1.2, and 44.39 ± 1.07, respectively. The difference between TIBC, mean serum free iron concentration, and transferrin saturation between Group I and Group III (for all, p values <0.001), as well as between Group II and Group III (p values 0.0012, 0.0015, and <0.0001, respectively) was statistically significant. The fasting plasma glucose values of Groups II and III were significantly higher than those of Group I, (p < 0.0001). Glycated haemoglobin (HbA1c) values were also shown to increase from Group I to II and then III, and the increase was highly significant (all p values <0.0001). Thus, decreased glycaemic control and an increase in the glycation of haemoglobin was the key to elevation in serum iron values and alterations in other parameters. However, a significant correlation was absent between serum iron and HbA1c (r = 0.05) and transferrin saturation (r = 0.0496) in Group III.

Conflicting effects of BMI and waist circumference on iron status

The association between obesity and iron status has a long history and is still receiving attention. However comparative analysis of the association between general obesity (BMI) and visceral obesity (waist circumference) with iron status has not been extensively researched. The aim of the present study is thus to determine if body mass index and waist circumference have the same correlation with iron status. One thousand one hundred and thirty people (225 men and 905 women) aged 30 years and above participated in this study. Anthropometric parameters, haemoglobin, iron and total iron binding capacity concentrations were measured using standard methods. Percentage transferrin saturation was calculated and ferritin concentrations were measured using an enzyme linked immunosorbent assay. Obese or overweight women had significantly lower iron and transferrin saturation concentration when compared to non-obese women. In contrast, women with high waist circumference had comparable plasma iron and transferrin saturation to women with normal waist circumference. Partial correlation analysis and linear regression analysis showed that BMI is negatively and significantly associated with plasma iron, transferrin saturation, Hb and ferritin concentration, whilst waist circumference is positively but insignificantly associated with plasma iron, transferrin saturation, Hb and ferritin concentration. Binary regression analysis showed that obese or overweight people are more likely to have iron deficiency, whilst those with raised waist circumference are more likely to have iron overload. Multivariate analysis showed that body mass index is negatively and significantly associated with low iron status, while waist circumference is positively and insignificantly associated with iron status. This is supported by a comparison of plasma iron, transferrin saturation and ferritin concentrations in participants with high body mass index and normal waist circumference and participants with normal body mass index and high waist circumference to those participants having normal body mass index and normal waist circumference. The present study suggests that in women body mass index is associated with low plasma iron, transferrin saturation and ferritin concentrations, while waist circumference is associated with high plasma iron, transferrin saturation and ferritin concentrations.

Association of total iron binding capacity with coronary artery disease

ObjectiveA case–control study and a meta-analysis were conducted to assess the association between total iron binding capacity (TIBC) and coronary artery disease (CAD) risk. MethodsA hospital-based case–control study was conducted with 258 CAD cases and 282 healthy controls. Logistic regression was utilized to estimate odds ratio (OR) with 95% confidence interval (CI) and adjust potential confounders. Dose–response relation was investigated between TIBC and CAD risk by dividing TIBC concentration into quartiles. A meta-analysis was performed on the standardized mean difference (SMD) as well as OR. ResultsIn our case–control study, TIBC was found associated with decreased CAD risk both in univariate (OR=0.981, 95% CI=0.975, 0.986) and multivariate (OR=0.979, 95% CI=0.972, 0.986) adjusted logistic regressions. The multivariate-adjusted OR for the highest quartile compared with the lowest quartile was 0.087 (95% CI=0.042, 0.181). After sensitivity analysis, the meta-analysis on SMD showed that TIBC was associated with decreased CAD risk (SMD=−0.211, 95% CI=−0.318, −0.104). The results of pooled measure on OR (OR=0.970, 95% CI=0.946, 0.995) were consistent with those of SMD analysis. ConclusionA weak association was found between TIBC levels and decreased CAD risk, further investigations are necessary to clarify the dose–response relationship.

HFE gene mutations and iron status of Brazilian blood donors

Mutations of the HFE and TFR2 genes have been associated with iron overload. HFE and TFR2 mutations were assessed in blood donors, and the relationship with iron status was evaluated. Subjects (N = 542) were recruited at the Hemocentro da Santa Casa de São Paulo, São Paulo, Brazil. Iron status was not influenced by HFE mutations in women and was independent of blood donation frequency. In contrast, men carrying the HFE 282CY genotype had lower total iron-binding capacity (TIBC) than HFE 282CC genotype carriers. Men who donated blood for the first time and were carriers of the HFE 282CY genotype had higher transferrin saturation values and lower TIBC concentrations than those with the homozygous wild genotype for the HFE C282Y mutation. Moreover, in this group of blood donors, carriers of HFE 63DD plus 63HD genotypes had higher serum ferritin values than those with the homozygous wild genotype for HFE H63D mutation. Multiple linear regression analysis showed that HFE 282CY leads to a 17.21% increase (P = 0.018) and a 83.65% decrease (P = 0.007) in transferrin saturation and TIBC, respectively. In addition, serum ferritin is influenced by age (3.91%, P = 0.001) and the HFE 63HD plus DD genotype (55.84%, P = 0.021). In conclusion, the HFE 282Y and 65C alleles were rare, while the HFE 63D allele was frequent in Brazilian blood donors. The HFE C282Y and H63D mutations were associated with alterations in iron status in blood donors in a gender-dependent manner.

HFE gene mutations and iron status of Brazilian blood donors

Mutations of the HFE and TFR2 genes have been associated with iron overload. HFE and TFR2 mutations were assessed in blood donors, and the relationship with iron status was evaluated. Subjects (N = 542) were recruited at the Hemocentro da Santa Casa de São Paulo, São Paulo, Brazil. Iron status was not influenced by HFE mutations in women and was independent of blood donation frequency. In contrast, men carrying the HFE 282CY genotype had lower total iron-binding capacity (TIBC) than HFE 282CC genotype carriers. Men who donated blood for the first time and were carriers of the HFE 282CY genotype had higher transferrin saturation values and lower TIBC concentrations than those with the homozygous wild genotype for the HFE C282Y mutation. Moreover, in this group of blood donors, carriers of HFE 63DD plus 63HD genotypes had higher serum ferritin values than those with the homozygous wild genotype for HFE H63D mutation. Multiple linear regression analysis showed that HFE 282CY leads to a 17.21% increase (P = 0.018) and a 83.65% decrease (P = 0.007) in transferrin saturation and TIBC, respectively. In addition, serum ferritin is influenced by age (3.91%, P = 0.001) and the HFE 63HD plus DD genotype (55.84%, P = 0.021). In conclusion, the HFE 282Y and 65C alleles were rare, while the HFE 63D allele was frequent in Brazilian blood donors. The HFE C282Y and H63D mutations were associated with alterations in iron status in blood donors in a gender-dependent manner.

Influence of infection on iron profile in severely malnourished children

To study the iron profile and find out an accurate diagnostic tool which reflects iron status in different types of infection in severely malnourished children aged 12 months to 71 months. Hundred and Eight (108) children of whom 72 children were infected and 36 non infected severely malnourished children according to WHO criteria in the age group of 12-71 months were interrogated. 36 healthy control in the same age group were also interrogated. Mean serum iron, total iron binding capacity (TIBC), ferritin concentration in normal children were significantly higher (P<0.001) than non-infected severely malnourished children. On the other hand mean serum ferritin concentration was significantly higher (P<0.001) in infected group than non-infected group but still lower than normal. Mean serum TIBC concentration significantly reduced in severely malnourished children than normal children but no significant difference was observed between non-infected and infected group. Mean serum iron, and transferrin saturation were significantly reduced (P<0.05) in parasitic infestation. Severely malnourished children had reduced mean serum iron profile. Parasitic infestation influenced the marked reduction of mean serum iron concentration and transferrin saturation level. Mean serum iron concentration was reduced in acute respiratory infection(ARI) and parasitic infestation than other infections. Serum ferritin concentration was elevated in all types of infection as acute phase protein but still lower than normal. So Iron, TIBC and Transferin saturation <16% constitute good evidence for iron deficiency in both infected and non-infected severely malnourished children.

Interaction Between Genotypes for HFE and TFR2 Genes Mutations and Iron Status in Brazilian Blood Donors

Hereditary hemochromatosis (HH) is a disorder characterized by increased intestinal iron absorption, which leads to a progressive accumulation of iron in the body. This iron overload has been associated with mutations in HFE gene (C282Y, H63D and S65C) and other genes. The objectives of this study were to assess the frequencies of functional mutations in HFE and TFR2 genes and to investigate their relationship with the iron status in a sample of blood donors. Blood donors (n=542) were recruited at the Hemocenter of the Santa Casa Hospital, Sao Paulo, Brazil. The genotypes for HFE (C282Y, H63D and S65C) TFR2 (Y250X and Q690P) gene mutations were evaluated by PCR-RFLP. The concentrations of serum iron and total iron-binding capacity (TIBC) were measured by automation system Advia®(Bayer Diagnostics) and serum ferritin by Axsym System®(Abbott Laboratories). The frequencies of HFE 282Y, HFE 63D and HFE 65C alleles were 2.1, 13.6 and 0.6%, respectively. The frequency C282Y allele (2.1%) in Brazilian blood donors is lower than that observed in blood donors from Northern Europe (5.1 to 8.2%, P<0.05). The TFR2 250X and TFR2 690P alleles were not found in these subjects. The iron status was similar between HFE genotypes in women. However, men carrying HFE 282CY genotype had higher serum ferritin and lower TIBC concentrations when compared to the HFE 282CC genotype carriers. HFE 282CY genotype was also associated with higher transferrin saturation in men who donated blood at the first time. Moreover, male donors with HFE 63DD plus 63HD genotypes had higher serum iron and transferrin saturation when compared to those with HFE 63HH genotype. A relationship between HFE CY/HH/SS haplotype and lower TIBC concentrations was also found in men. The HFE 282Y and HFE 65C alleles were rare while the HFE 63D was frequent in blood donors. The mutations in TFR2 gene were not found in this study. The HFE 282Y and HFE 63D alleles were associated with alterations on iron status only in male blood donors.

Effect of Green Tea on Iron Status and Oxidative Stress in Iron-Loaded Rats

Plasma non-transferrin bound iron (NTBI) is potentially toxic and contributes to the generation of reactive oxygen species (ROS), consequently leading to tissue damage and organ dysfunction. Iron chelators and antioxidants are used for treatment of thalassemia patients. Green tea (GT) contains catechins derivatives that have many biological activities. The purpose of this study was to investigate the iron-chelating and free-radical scavenging capacities of green tea extract in vivo. Rats were injected ip with ferric citrate together with orally administered GT extract (GTE) for 4 months. Blood was collected monthly for measurement of iron overload and oxidative stress indicators. Plasma iron (PI) and total iron-binding capacity (TIBC) were quantified using bathophenanthroline method. Plasma NTBI was assayed with NTA chelation/HPLC. Plasma malonyldialdehyde (MDA) was determined by using the TBARS method. Erythrocyte oxidative stress was assessed using flow cytometry. Levels of PI, TIBC, NTBI and MDA, and erythrocyte ROS increased in the iron-loaded rats. Intervention with GT extract markedly decreased the PI and TIBC concentrations. It also lowered the transferrin saturation and effectively inhibited formation of NTBI. It also decreased the levels of erythrocyte ROS in week 4, 12 and 16. Therefore, green tea extract can decrease iron in plasma as well as eliminate lipid peroxidation in plasma, and destroy formation of erythrocyte ROS in the rats challenged with iron. The bifunctional effects could be beneficial in alleviating the iron and oxidative stress toxicity. In prospective, these GTE activities should be further examined in thalassemic animals or humans.

Relationship between total iron binding capacity and transferrin concentration in neonatal piglets treated with iron-dextran

Serum iron concentration and iron saturation of transferrin (Trf) are measures of body iron stores after administration of iron supplements. In clinical and experimental research, the complex determination of Trf was replaced by the simple determination of total iron binding capacity (TIBC). The objective of this work was to define if TIBC could be an adequate measure for Trf in neonatal piglets after i.m. iron administration. Treated piglets received 150 mg of iron-dextran i.m. the first day of life, and were compared to the untreated control group. Prior to iron administration, as well as on days 2, 8 and 12 after iron administration, serum iron and TIBC concentration were analyzed by an automatized chemical analyzer and Trf was determined by densitometry of electrophoretic strips. Our results show that regardless of iron treatment, TIBC is not a measure of Trf concentration in neonatal piglets two days after birth. At day 8 of their life a high correlation coefficient of these two parameters was established in non-treated animals, while in iron-treated piglets the same correlation was established 12 days after iron treatment. Thus, we suggest that in neonatal piglets, TIBC could be used as a measure of Trf concentration only 12 days after i.m. iron treatment.

Performance characteristics of the Dimension RxL iron and total iron-binding capacity methods

Background: Measurements of serum iron and total iron-binding capacity (TIBC) can be used to aid the diagnosis of iron deficiency and iron overload states. A variety of different methods for these measurements are commercially available. Methods: Linearity, imprecision and hemoglobin interference of homogeneous iron and TIBC methods on a Dimension® RxL analyzer were assessed. Method comparison studies were performed with a Vitros® 950 analyzer. Results: The Dimension RxL iron method was linear from 40 to 1000 μg/dl. The coefficient of variation of the iron and TIBC methods were <4% and <2%, respectively, at iron concentrations of 68 and 228 μg/dl and TIBC concentrations of 206 and 384 μg/dl. Comparison of the Vitros 950 and Dimension RxL iron methods gave a slope of 0.97, an intercept of 6.0 and r=0.99. Corresponding results for the TIBC methods were 1.02, −6.6 and r=0.97, respectively. Simulation of acute iron overload in vitro did not produce the same effect on TIBC measurements as in vivo overload. Iron recovery by the Dimension RxL method was reduced 40–60% by the addition of deferoxamine at a concentration of 200 μmol/l. Conclusions: The Dimension RxL assay provides acceptable measurements of iron and TIBC in routine patient samples. Iron measurements are unreliable in the presence of deferoxamine.

The relation between chemically measured total iron-binding capacity concentrations and immunologically measured transferrin concentrations in human serum

We sought to determine if serum total iron-binding capacity (TIBC) is equivalent to serum transferrin (TRF) so that a low-cost colorimetric chemical assay for unsaturated iron-binding capacity (UIBC) could be substituted for a high-cost immunologic assay for TRF. Our study design included independent and blinded measurements of UIBC, serum iron, and TRF concentrations in human serum samples. Data from five independent correlation studies carried out at three different Quest Diagnostics laboratories were combined into one data set containing 570 paired results for TIBC and TRF. r2 was 0.941 when three outliers were eliminated from the 570-sample data set. Scatter about the regression line was fully accounted for by the CVs for the TIBC and TRF assays. When each test is measured precisely and without bias, the ratio of TIBC (mumol/L) to TRF (g/L) in SI units is close to the theoretically expected value of 25.0.

Transferrin Index: An Alternative Method for Calculating the Iron Saturation of Transferrin

We surveyed 140 clinical chemistry laboratories in Australia to establish which laboratory methods they used to determine serum iron status: 125 measured serum iron (Fe), 85 measured transferrin (TRF), 47 measured total iron-binding capacity (TIBC), and 14 measured both TRF and TIBC. Of the 55 laboratories routinely reporting TRF saturation (TS), 16 calculated TS directly as (Fe/TIBC) x 100, and 9 used [Fe/(TRF x 2)] x 100. Thirty laboratories measured TRF and converted it to an equivalent TIBC concentration; the derived TIBC was then used to calculate TS. We measured iron, TIBC, and TRF concentrations in 94 control subjects, 59 patients with alcoholic liver disease (ALD), and 20 with proven genetic hemochromatosis (GH). TS was compared with a transferrin index (TI = Fe/TRF) to determine whether both methods were sensitive for GH screening and which method gave the fewest false-positive results with discrimination limits of > 55% and > 1.0, respectively. All GH patients were detected by both TS and TI at these limits. One control subject had a TI > 1.0, whereas three control subjects had a TS > 55%. Nine patients with ALD had a TI > 1.0 and 11 ALD patients had a TS > 55%. Some iron-overload patients had lower than expected TS values compared with TI, possibly because of ferritin interference in the TIBC assay. Also, the precision of the TRF assay was better than that of the TIBC assay: CVs of 1.85-3.68% vs 6.17%. We therefore recommend that calculated TI replace TS in screening for iron overload.

The relationship between decreased iron stores, serum iron and neonatal hypoglycemia in large-for-date newborn infants.

We assessed the relationship between neonatal hypoglycemia and newborn iron status in 15 hypoglycemic, large-for-date newborn infants, 12 of whom were infants of diabetic mothers. These infants had significantly lower mean serum iron concentrations, ferritin concentrations, percent iron-binding saturation and calculated iron stores, and significantly higher mean transferrin concentrations, total iron-binding capacity concentrations and mid-arm circumference:head circumference ratios when compared with either 15 euglycemic large-for-date or 15 euglycemic appropriate-for-date control infants (p less than 0.001 for all comparisons). All hypoglycemic infants had ferritin concentrations below the 5th percentile as compared to 3% of controls (p less than 0.001), and 67% had transferrin concentrations above the 95th percentile (controls: 0%; p less than 0.001). Only the hypoglycemic infants demonstrated a significant negative linear correlation between ferritin and transferrin concentrations (r = -0.83; p less than 0.001). Decreased serum iron concentrations were associated with size at birth (r = -0.60; p = 0.01) and with increased red cell iron (r = -0.60; p = 0.01), implying a redistribution of iron dependent on the degree of fetal hyperglycemia and hyperinsulinemia. Infants with increased red cell iron had more profound neonatal hypoglycemia. These results show a significant association between decreased iron stores and neonatal hypoglycemia in macrosomic newborn infants associated with a significant shift of iron into red blood cells.

The effects of age, live-weight gain and feed intake on the blood composition of young calves

SummaryBlood samples were taken each week from 30 individually-reared heifer calves between 1 and 13 weeks of age and analysed for packed cell volume, blood glucose and Hb; and serum albumin, urea-nitrogen, total protein, inorganic phosphate, Ca, Mg, K, Na, Fe and total iron-binding capacity. All calves were weaned by 6 weeks of age, and were fed ad libitum.There were significant changes (P &lt; 0·001) in blood concentrations with age for most constituents. Concentrations of albumin and Fe increased and of K decreased steadily over the whole of the period. Glucose and total iron-binding capacity concentrations decreased until about the 6th week of life and then increased.There were significant correlations (P &lt; 0·05) for both the calves' weight gain and their feed intake from 6 to 13 weeks with the mean concentrations of glucose, inorganic phosphate, Na, albumin and total iron-binding capacity over the same period. Weight gain during this period was also correlated with serum Fe concentration. When weight gains were adjusted for the feed intake, the correlations between weight gain and the concentrations of all blood constituents became insignificant.There was a significant correlation (P &lt; 0·05) between weight gain after 6 weeks of age and Hb concentration before 6 weeks. However, when weight gain was adjusted for birth weight, this correlation became insignificant.