Serum ferritin and erythrocyte 2,3-DPG during quantitated phlebotomy and iron treatment

Diagnosis and prevention of iron deficiency and iron-deficiency anemia in infants and young children (0-3 years of age)

This clinical report covers diagnosis and prevention of iron deficiency and iron-deficiency anemia in infants (both breastfed and formula fed) and toddlers from birth through 3 years of age. Results of recent basic research support the concerns that iron-deficiency anemia and iron deficiency without anemia during infancy and childhood can have long-lasting detrimental effects on neurodevelopment. Therefore, pediatricians and other health care providers should strive to eliminate iron deficiency and iron-deficiency anemia. Appropriate iron intakes for infants and toddlers as well as methods for screening for iron deficiency and iron-deficiency anemia are presented.

Effect of sodium iron ethylenediaminetetra-acetate (NaFeEDTA) on haemoglobin and serum ferritin in iron-deficient populations: a systematic review and meta-analysis of randomised and quasi-randomised controlled trials

We aimed to synthesise evidence to assess the effect and safety of NaFeEDTA on Hb and serum ferritin in Fe-deficient populations. We performed a systematic review, identifying potential studies by searching the electronic databases of Medline, Cochrane Library, Embase, WHO Library and China National Knowledge Infrastructure. We also hand-searched relevant conference proceedings and reference lists. Finally, we contacted experts in the field. The selection criteria included randomised or quasi-randomised controlled trials of NaFeEDTA compared with placebo. Hb, serum ferritin and adverse effects were outcomes of interest. Inclusion decisions, quality assessment and data extraction were performed by two reviewers independently. Seven studies met the inclusion criteria. All included studies assessed the effect of NaFeEDTA on Hb concentration, four studies assessed the effect on serum ferritin concentration, and one study on serum Zn concentration. After the intervention, Hb concentration and serum ferritin concentration were both higher in the NaFeEDTA group compared with the control group. For Hb, data from six studies could be pooled and the pooled estimate (weighted mean difference) was 8·56 (95 % CI 2·21, 14·90) g/l (P = 0·008). For serum ferritin, data from four studies could be pooled and the pooled difference was 1·58 (95 % CI 1·20, 2·09) μg/l (P < 0·001). Subgroup analysis indicated that a lower baseline Hb level was associated with a greater increase in Hb concentration. No significant difference in serum Zn concentration was found. We concluded that NaFeEDTA increased both Hb concentration and serum ferritin concentration substantially in Fe-deficient populations, and could be an effective Fe preparation to combat Fe deficiency.

Serum Ferritin is a Reliable, Non-invasive Test for Iron Status in Pregnancy: Comparison of Ferritin with Other Iron Status Markers in a Longitudinal Study on Healthy Pregnant Women; Erythropoiesis

Background and Aims: To assess the true positive and false positive rates of the iron status markers (serum iron, serum transferrin, transferrin saturation, haemoglobin, haematocrit, mean corpuscular volume (MCV), mean cell haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), erythrocyte count) in the diagnosis of depleted iron stores (iron depletion) during normal pregnancy and postpartum. Methods: Among 120 pregnant women, 58 were randomised to placebo-treatment and 62 to iron-treatment (66 mg ferrous iron daily from 14 weeks of gestation). Iron status markers were measured every 4th week during pregnancy and 8 weeks postpartum. Iron depletion was defined by a serum ferritin concentration < 16 &mgr;g/L. The 5th percentiles for the other iron status markers in the group of iron-treated women were used as cut-off values. Calculations were made in the 2nd and 3rd trimester, praepartum and postpartum. Results: In general, the true positive rates of other iron status markers in the diagnosis of iron depletion (serum ferritin < 16 &mgr;g/L) were low ranging from 0% to 52% during pregnancy and from 9% to 64% postpartum. Transferrin saturation and MCH displayed the highest true positive rates. The false positive rates ranged from 0% to 13% during pregnancy and from 4% to 17% postpartum. Haemoglobin and MCH displayed the highest false positive rates. Conclusions: The sensitivities of the other iron status markers were too low and the false positive rates too high to be of clinical value in the diagnosis of iron depletion. Despite physiologic variations due to haemodilution, the serum ferritin concentration is currently the most reliable non-invasive marker of iron status in pregnancy and postpartum.

The effect of intramuscular iron injections on serum ferritin levels and physical performance in elite netballers

The purpose of this study was to determine the effect of iron supplementation by intramuscular injection on both serum ferritin (SF) levels and exercise performance in iron depleted, non-anaemic elite female netballers. Fifteen iron depleted (Serum Ferritin <40 ug x L(-1). Haemoglobin >125 g x L(-1)) subjects (19+/-3 y) first performed their routine test battery: a vertical jump test, a 10s power and 5x6s repeat sprint test on a cycle ergometer and a 20m multi-stage shuttle run. Subjects were matched on the basis of height, mass, and playing position and then assigned to either a Ferritin Group (FG) or Placebo Group (PG) (single blind design). Subjects then underwent a course of 5x2ml intramuscular injections of either Ferrum H (FG) or normal saline (PG) over a period of 8-10 days before repeating the blood and physical performance tests. Five and 10 days following supplementation, SF levels in the FG increased significantly from baseline levels (P<0.05) and were also significantly greater than levels measured in the PG (P<0.01). Haemoglobin levels remained unchanged in both groups. All test scores remained unchanged from baseline values and were not different between the two groups. These results demonstrate that a course of 5x2ml intramuscular iron injections significantly increased SF concentration within 2 weeks without increasing Hb levels, but this rapid elevation did not enhance the physical performance in selected tests of iron depleted, non-anaemic athletes.

Plasma ferritin concentration and physical work capacity in athletes

This investigation aimed to determine whether the physical work capacity of nonanemic athletes could be improved when plasma ferritin concentrations of below 30 ng/ml were raised at least 15 ng/ml. The experimental group consisted of 15 training athletes, each of whose plasma ferritin concentration was less than 30 ng/ml (mean and SD of 19.8 +/- 8.4 ng/ml). In a control group of 16, each was measured with a plasma ferritin concentration of more than 40 ng/ml (mean and SD of 83.3 +/- 37.6 ng/ml). All participated in submaximal and maximal tests for aerobic and anaerobic power. Following iron supplementation, plasma ferritin concentration in each experimental subject increased by at least 15 ng/ml to more than 30 ng/ml, to a new mean of 46.3 +/- 15.5 ng/ml. The performance measures were also repeated, but no significant overall effects were associated with the increased plasma ferritin concentrations. These data provide no sound evidence that physical work capacity of athletes is enhanced when plasma ferritin concentrations of around 20 ng/ml are increased by at least 15 ng/ml.

Physiological response to phlebotomies for autologous transfusion at elective hip-joint surgery

In order to study the physiological response to phlebotomies for autotransfusion, an autotransfusion program was designed for 10 patients undergoing hip-joint replacement surgery for arthrosis. 4 phlebotomies of 450 ml each were performed within 12 days. Blood samples were taken immediately before phlebotomy for blood hemoglobin (Hb), serum erythropoietin (Epo), reticulocyte count (ret) and erythrocyte 2,3-diphosphoglycerate (DPG). All 4 phlebotomies could be performed in 9/10 patients, and only 1 patient had significant symptoms (fatigue). The operation was performed 2 weeks after the last phlebotomy. None of the patients had recovered the initial Hb level at operation (24.8 +/- 9 per liter lower than initially), and they were all even more anemic after the operation (36.8 +/- 16.9 g/l lower than initially). Serum Epo increased from 13.6 +/- 7.2 IU to 30.6 +/- 12.2 (SD) IU per liter, and reticulocyte counts increased to a maximum of 3.68 +/- 1.69%. DPG increased in all patients except the one who had significant fatigue. It is concluded that the patients tolerated the phlebotomy program well but that a significant anemia developed. The compensatory increase in erythropoietin and reticulocyte count, adequate for this degree of anemia, was small compared to the increase seen at more severe anemia, indicating that there may be a role for pharmacological stimulation of erythropoiesis in blood predeposit programs.

Diagnosis and clinical evaluation of iron overload

Diagnostic evaluation of the various forms of iron overload requires information about the total amount and distribution of iron stores. Direct information on the quantity of storage iron can be obtained only by its mobilization in response to repeated phlebotomy or after dilution of a labelled iron test dose in the total body iron pool. Both approaches are cumbersome and time-consuming and are suitable only for research purposes. Detailed information on the amount and distribution of tissue iron in iron overload can be obtained from biopsy specimens of the major iron storage organs such as the liver and bone marrow. However, the invasive nature of these procedures limits their clinical usefulness. Indirect measures, such as serum iron concentration, TIBC saturation, serum ferritin, chelate-induced urinary iron excretion or intestinal iron absorption, and ferrokinetic measurements may provide useful information on the amount of total body iron reserve. However, they all have important limitations in their diagnostic use for evaluating iron overload. The most suitable indirect storage iron index among these methods is the ferritin assay, which has a well established place in the diagnosis of iron overload and monitoring of the effect of therapy. Recent developments in physical methods such as CT, SQUID and NMR have significantly improved the applicability of these techniques for non-invasive measurement of liver iron. It is expected that quantitative measurement of hepatic iron stores will soon be integrated into the diagnostic procedures available by imaging techniques such as CT and NMR. In combination with screening parameters such as serum ferritin and TIBC saturation these new but expensive diagnostic tools may simplify and shorten the diagnostic process and may also be useful for monitoring the treatment of iron overload by phlebotomy or chelating drugs.

Erythrocyte 2,3-diphosphoglycerate and erythropoietic activity in rabbits with severe bleeding anaemia superimposed in the early post-natal fall in haemoglobin

Erythrocyte 2,3-diphosphoglycerate (2,3-DPG), whole blood haemoglobin (Hb), haematocrit (Hct), mean corpuscular haemoglobin concentration (MCHC) and reticulocyte percentage (Rt) were determined before and after bleeding in two groups of suckling chinchilla rabbits. One group was subjected to severe bleeding on the 12th, 15th, 18th and 21st day after birth and studied for 3 weeks, while the other was studied during the first 24 h after one severe bleeding on the 18th day. In the first group Hb and Hct fell to 2.7 g . dl-1 and 11.5%, respectively, on the 25th day. The fall was accompanied by a marked rise in Rt and decline in MCHC, reaching maximum and minimum on the 29th day, and a simultaneous, temporary decline in 2,3-DPG. In the other group the acute bleeding was accompanied by a marked fall in Hb and Hct, but no change in Rt and MCHC. 2,3-DPG was unchanged 8 h after the bleeding, but showed a rise during the following 16 h, definitely beyond the normal rise at this age. It is concluded that severe bleeding anaemia induces a rise in erythrocyte 2,3-DPG synthesis. However, the effect of the acute rise in 2,3-DPG is far from sufficient to maintain the O2 delivery capacity of the blood, and is completely offset by the influence of a subsequent change in the erythrocyte population towards younger cells with low 2,3-DPG.

Erythrocyte and plasma ferritin in normal subjects, blood donors and iron deficiency anemia patients

Ferritin concentration has been determined with an immunoradiometric assay in plasma and washed sedimented erythrocytes after hypotonic lysis. There was a gradual decrease of plasma ferritin in the sequence normal males, normal females, blood donors and patients with iron deficiency anemia. Erythrocyte ferritin remained unchanged in normal males and females and in blood donors, but dropped significantly in the anemic patients. Correspondingly, the ratio of erythrocyte to plasma ferritin rose from less than 2 in healthy males up to 8 in persons with iron deficiency. Little, if any effect on plasma and erythrocyte ferritin was observed in 12 male and female volunteers when taking iron for 4 weeks. In 2 patients with iron deficiency anemia the blood counts were normalized within 2-3 months during oral iron substitution, accompanied by a drastic increase of the erythrocyte ferritin concentration to values far above normal. In contrast, the plasma ferritin concentration remained below normal. Thus, in iron deficiency erythrocyte ferritin is synthesized with priority in the presence of iron and, in addition to plasma ferritin, appears to be a useful parameter of the iron status.

[Serum ferritin in differential diagnosis of anemia (author's transl)]

The concentration of ferritin in the serum of normal males (n = 79) was 98 micrograms/l (geometric mean) with a 95% confidence range of 21-447 micrograms/l. In non-menstruating healthy females (n = 39), the concentration was 85 (26-279) micrograms/l. In menstruating females, serum ferritin was less than 30 micrograms/l only when the duration of menstruation was more than or equal to 4 days. Patients with uncomplicated iron-deficiency anemia had a serum ferritin level less than 20 micrograms/l. After oral or parenteral iron therapy, serum ferritin was greater than 20 micrograms/l in 7 to 17 patients. Serum ferritin was greater than 20 micrograms/l in 8 of 12 patients with a simultaneous inflammatory or malignant disease. Of patients with iron-deficiency anemia, 86% had a serum ferritin level lower than 40 micrograms/l. A serum ferritin level less than 40 micrograms/l was only observed in patients with iron-deficiency anemia and not in patients with other forms of anemia. Of patients with iron-deficiency anemia and a hemoglobin concentration lower than 100 g/l, 80% had a serum iron level less than 13 mumol/l and a total iron binding capacity higher than 70 mumol/l. Anemia of chronic disorders was diagnosed with a sensitivity of 0.93 and a specificity of 0.92 in patients with serum iron less than 13 mumol/l, total iron binding capacity less than 60 mumol/l, erythrocyte sedimentation rate greater than 25 mm in the first hour, and serum fibrinogen greater than 4 g/l. Somewhat better was the same combination except with the serum ferritin level greater than 50 micrograms/l instead of the iron binding capacity. However the predictive value using both combinations was too low.

The laboratory evaluation of microcytic red blood cells

Microcytic red blood cell states are common clinical problems in both adult and pediatric age groups. The recent widespread availability of electronic blood cell counters for performing routine blood counts has increased the detection of microcytic red blood cells. Physicians must workup both symptomatic and asymptomatic patients with microcytic red blood cells before they can initiate proper therapy and/or counseling. The purpose of this review is threefold: (1) to discuss the causes of microcytic red blood cells in terms of disorders of decreased heme production vs. disorders of decreased globin production, (2) to review the clinical laboratory tests useful in differentiating microcytic red blood cell states, and (3) to present a practical approach for the laboratory workup of microcytic red blood cells.

Changes in serum ferritin levels after intravenous iron

The effect of intravenous iron dextran on serum ferritin levels was observed in two patients with iron deficiency anaemia. Serum ferritin levels rose sharply and reached peak levels seven to nine days after infusion when at least 90% of the infused iron had been removed from the plasma. A linear relation was shown for each patient between the logarithm of the serum ferritin levels and the logarithm of the calculated cellular non-haem iron levels.

Serum ferritin in the regulation of iron therapy in blood donors

12 regular blood donors were selected on the basis of subnormal serum ferritin levels as a criterion for iron deficiency. It was found that all had high transferrin levels but only 5 had subnormal serum iron or transferrin saturation. The donors were given oral iron therapy in a dose of 2,800 mg between each phlebotomy, and the donation interval was standardized to 8 weeks. Test samples were collected every 4th week. After an initial rise in ferritin during the first 2 months, 6 of the donors again had subnormal serum ferritin levels, and the iron dose was therefore doubled after 32 weeks. Following this, all subjects taking the higher dose had normal ferritin values and stainable marrow iron was found at the end of the study, after 92 weeks. 3 subjects did not take the higher dose, had no raised serum ferritin level or stainable hemosiderin. It is concluded that serum ferritin estimation can be used to monitor the therapy in blood donors so that a satisfactory amount of iron is stored.

Serum ferritin in the elderly

A two-site immunoradiometric assay for human ferritin has been developed using antibody-coated polystyrene tubes. Serum ferritin was measured in fifty-four men and women aged 73 years. The geometric mean was 166 micrograms/l for thirty-one men and 161 micrograms/l for twenty-two women. One woman was excluded from the statistical calculations. Twenty-eight of the subjects had earlier participated in a study of food consumption by the duplicate portion technique. There was a significant correlation (r = 0.44, P < 0.01) between the food iron intake and the serum ferritin values. A reference material of men and women aged 18-55 years was also analysed. The geometric mean for males was 170 micrograms/l with a 95% confidence range of 46-637 micrograms/l. The female controls were found to have significantly lower values (geometric mean 51 micrograms/l, 95% confidence range 10-260 micrograms/l) than both the older women (P < 0.001) and the male controls (P < 0.001).

Investigation of pregnancy-related changes in red cell 2,3-diphosphoglycerate

Significant gestational changes in red cell 2,3-DPG were found. No significant correlation was found between these pregnancy-related changes and alterations in the parameters of iron metabolism or red cell enzymes during the same gestational period. Possible reasons for the high concentration found at 21--24 weeks gestation are discussed.

Serum ferritin

(1) Brief introduction to iron metabolism and the biochemistry of ferritin. (2) Early studies of circulating ferritin. (3) Methods for measuring serum ferritin concentrations -- immunoradiometric, radioimmuno- and enzyme-linked immuno assays based on liver or spleen ferritin -- an evaluation of these techniques. (4) Serum ferritin concentrations in normal subjects -- definition of normality -- relationship between storage iron and serum ferritin concentrations -- changes during development from birth to old age -- iron deficiency -- variability of serum ferritin concentration -- evaluation of use of ferritin assay for assessment of storage iron levels. (5) Serum ferritin concentrations in disease -- hemochromatosis -- secondary iron overload -- liver damage -- infection and chronic disease -- cancer. (6) Assay of serum ferritin with antibodies to ferritins other than liver or spleen -- ferritinemia and cancer. (7) Properties of serum ferritin -- molecular weight -- iron content -- isoelectric focusing patterns -- carbohydrate content -- immunological properties. (8) Physiology of circulating ferritin -- release of ferritin from tissues -- origin of circulating ferritin -- clearance from the plasma -- iron and protein turnover. (9) Summary -- factors influencing serum ferritin concentrations and clinical use of ferritin estimations.

Serum ferritin during infection. A longitudinal study

Serum ferritin, transferrin, iron and haptoglobin have been investigated in a longitudinal study in 18 patients hospitalized for various acute infections. Within a couple of days after the onset of an infection, a rise in serum ferritin was seen, the magnitude of which was not dependent on the type of infection (bacterial or viral). The serum ferritin level remained elevated for several weeks in some patients, and 7 out of the 18 patients still had abnormally high values 5 weeks after the onset of illness. The mean curves for serum ferritin and the acute phase reactant haptoglobin were parallel. Possible mechanisms causing the elevation in serum ferritin are discussed.