Screening with zinc protoporphyrin for iron deficiency in non-anemic female blood donors

Iron-depleted donors are at increased risk of developing anemia; if these donors could be identified by a screening test, iron supplementation or decreased donation frequency could be considered. Tests to determine serum ferritin, blood hemoglobin, and erythrocyte (Erc)-zinc protoporphyrin concentrations were examined in 679 consecutive female blood donors to identify donors with non-anemic iron deficiency. The test to determine serum ferritin is expensive and slow, whereas the two latter tests are rapid and less costly and could therefore be used for screening. Women in the fertile age groups had the lowest average serum ferritin values. In all, 93 women (13.7%) had depleted iron stores, as indicated by serum ferritin concentrations less than 14 micrograms/L. In these women, a much better correlation was found between Erc-zinc protoporphyrin and serum ferritin (rs = -0.49, P less than 0.001) than between blood hemoglobin and serum ferritin (rs = 0.31, P less than 0.01). These findings suggest that measurement of Erc-zinc protoporphyrin is superior to that of blood hemoglobin in identifying donors with non-anemic iron deficiency.     

Iron balance in superdonors

Volunteers who are able to donate blood frequently without becoming anemic provide a unique opportunity to observe iron balance under conditions of controlled blood loss. The 88 men and 88 women studied had given a mean of 17 donations (range 10–24) over 4 years. Twenty- seven percent of men and 45 percent of women took iron-containing supplements. In these "superdonors," estimated iron loss averaged 3.8 mg/day in men, 3.4 mg/day in menstruating women and 3.0 mg/day in nonmenstruating women. Dietary iron consumption estimated from the dietary history averaged 17 mg/day for men and 13 mg/day for women; in general, the superdonors consumed a superior diet. Sixty-three percent of the unsupplemented individuals had ferritin values less than 20 micrograms/l. Assuming that stores were constant, these individuals would have to absorb 25 percent of their dietary iron to meet total iron loss. Supplemented men and women taking an average of 24 and 34 mg of additional iron per day, respectively, showed relatively little difference in iron balance from unsupplemented individuals; 58 percent had serum ferritin values of less than 20 micrograms/l, and 28 percent were equal to or less than 12 micrograms/l. The low level of absorption (6-9%) in supplemented individuals suggests that the iron availability of iron-containing preparations ingested may have been poor.     

Menstrual Suppression, Iron Homeostasis, and Disease Risk

Menstrual blood loss may reduce risk of atherosclerotic cardiovascular and other diseases in premenopausal women (compared to men of comparable age and postmenopausal women) by maintaining relatively low levels of body iron as measured by the serum ferritin. The impact of menstrual suppression and cessation has not been adequately studied for the effects on ferritin levels or disease risk. Evidence for increased disease risk with rising body iron stores and effects of menstrual suppression on iron homeostasis are reviewed. We postulate that monitoring ferritin levels may guide preservation of optimal iron stores to reduce disease risk during menstrual suppression and cessation.     

Serum ferritin iron in iron overload and liver damage: correlation to body iron stores and diagnostic relevance

The iron content of serum ferritin has been determined in groups of patients with normal or increased iron stores by using a technique of ferritin immunoprecipitation followed by iron quantitation with atomic absorption spectroscopy. The results were correlated to individual liver iron concentrations, measured non-invasively by superconducting quantum interference device (SQUID) biomagnetometry. A close correlation between serum concentrations of ferritin protein and ferritin iron was found (r = 0.92) in all groups of patients. However, the correlation between ferritin iron concentration and individual liver iron concentration was poor in patients with hemochromatosis (r = 0.63) and patients with beta-thalassemia major (r = 0.57). The degree of ferritin iron saturation was about 5% in iron-loaded patients, which contrasts with results in two recent studies but confirms older observations. In patients with liver cell damage, the ferritin iron saturation in serum was significantly higher than that found in groups with iron overload disease, probably indicating the release of intracellular iron-rich ferritin into the blood. The monitoring of patients undergoing bone marrow transplantation indicated that the release of iron-rich and iron-poor ferritin occurred during phases of hepatocellular damage and inflammation, respectively. We find the benefits of serum ferritin iron measurement to be marginal in patients with iron overload disease.     

Iron stores in male blood donors evaluated by serum ferritin

Iron stores were evaluated by serum ferritin measurements in 1348 male blood donors. Blood donation was associated with a decrease in serum ferritin concentrations. First-time donors (n = 21) had a geometric mean serum ferritin concentration of 52 micrograms per l, and multiple-time donors (n = 1327) of 36 micrograms per l (p less than 0.01). In the donating population, 6.0 percent had serum ferritin values less than 15 micrograms per l (i.e., depleted iron stores), 33.9 percent had values from 15 to 30 micrograms per l (i.e., reduced iron stores), 52.5 percent had values from 31 to 90 micrograms per l, and 7.6 percent had values greater than 90 micrograms per l (i.e., normal iron stores). The frequency of donations per year was more predictive of decreased iron stores than the number of lifetime donations. Serum ferritin showed a moderate fall up to the fourth donation (p less than 0.001); thereafter serum ferritin levels showed only minor insignificant changes. An increase in donation frequency was accompanied by a significant decrease in serum ferritin; values less than 15 micrograms per l were found in 1.3 percent of donors bled two times per year, in 6.0 percent bled three times per year, and in 7.9 percent bled four times per year. Regular monitoring of iron stores by serum ferritin in blood donors seems justified in order to identify those with depleted iron stores who will benefit from iron supplementation.     

The value of routine ferritin measurement in blood donors

BACKGROUND: Iron store deficiency is a common side effect of whole blood donation. Early recognition and reversal of excessive iron loss may avoid symptomatic iron store depletion in blood donors and reduce volunteer loss due to iron deficiency (ID) anemia. STUDY DESIGN AND METHODS: Between 1996 and 2009, a total of 160,612 visits with the intention to donate blood by 23,557 healthy volunteers were recorded at our center. As of 2004, routine serum ferritin testing and additional counseling of donors at risk for donation‐induced anemia were implemented. We analyzed the impact of this measure on the hemoglobin (Hb) levels and anemia occurrence in our donor population and in particular in women of childbearing age. Donation rejections due to low Hb counts, the intervals to next donation, and return rates thereafter were also assessed. RESULTS: The introduction of routine serum ferritin analysis resulted in an increase of mean Hb levels in blood donors particularly in women of childbearing age. The incidence of predonation anemia and donation ineligibility due to a low Hb concentration decreased significantly. The return intervals of donors rejected on account of low Hb levels were shortened; however, the return rates thereafter were also curtailed. CONCLUSIONS: Systematic serum ferritin measurements allowed an optimized management of ID in our donors and efficacious prevention of ID anemia.     

A genetic risk factor for low serum ferritin levels in Danish blood donors

BACKGROUND: Iron deficiency is a frequent side effect of blood donation. In recent years, several studies have described genetic variants associated with iron concentrations. However, the impact of these variants on iron levels is unknown in blood donors. Knowledge of genetic variants that predispose donors to iron deficiency would allow bleeding frequency and iron supplementation to be tailored to the individual donor. STUDY DESIGN AND METHODS: The genotypes of five specific single‐nucleotide polymorphisms (SNPs) in three genes that have been previously associated with iron status and/or restless leg syndrome (RLS) were investigated in two groups of female blood donors. The first group had low iron stores (serum ferritin ≤ 12 µg/L, n = 657), and the second group had normal to high iron stores (serum ferritin > 30 µg/L, n = 645). Genotype distribution for each of the SNPs was compared between the two groups. RESULTS: Homozygosity for the T‐allele of BTBD9 rs9296249 was associated with lower serum ferritin. The odds ratio for low serum ferritin was 1.35 (95% confidence interval, 1.02‐1.77; p = 0.03) when comparing donors with the TT genotype with donors with the CT genotype. CONCLUSION: A frequent polymorphism in BTBD9 was significantly associated with serum ferritin. This polymorphism has previously been associated with RLS, but not low iron stores in blood donors.     

The relationship between red blood cell and reticulocyte indices and serum markers of iron status in the cord blood of newborns.

BACKGROUND: The aims of this study were to assess the relationship between red blood cell and reticulocyte indices and biochemical iron status measurements, and to define reference values of these markers in the cord blood of newborns. METHODS: In cord blood samples from 199 full-term newborns, cellular indices were assessed using an ADVIA 120 hematology system and iron status was analyzed by measurement of serum iron, transferrin, transferrin saturation (TfSat), transferrin receptor (TfR) and ferritin. RESULTS: Cellular hemoglobin in red blood cells or reticulocytes was independent of serum iron markers such as TfSat, TfR and ferritin. The percentage of hypochromic red blood cells (%HYPOm) and reticulocytes (%HYPOr) correlated significantly with TfSat and TfR-F index (TfR/log ferritin). Importantly, %HYPOm and %HYPOr were also positively correlated with the high immature reticulocyte fraction (IRF-H) and the mean cell volume of red or reticulocytes. CONCLUSIONS: In newborns, accelerated erythropoiesis is a major contributor to red blood cell and reticulocyte indices, which provide conflicting results when compared with serum markers of iron status. Apparently, the serum proteins ferritin, transferrin and TfR are more appropriate tools for the diagnosis of iron status in newborns.     

Body iron status in critically ill patients: significance of serum ferritin

Serial measurements of blood haemoglobin, serum iron, serum transferrin, total iron-binding capacity, transferrin per cent saturation and serum ferritin were determined in 51 post-operative critically ill patients to investigate body iron status in severely stressed patients. The results showed decreased blood haemoglobin, serum iron, serum transferrin and transferrin saturation compared to an increase in serum ferritin levels. These results indicate that there is inadequate availability of iron to tissues (secondary to rearrangement of body iron to the advantage of the iron storage compartment), which is often present in severely critically ill patients. A positive correlation was found between the initial (ferritin) levels and SAPS (r=0.41,p< 0.01). In addition, the increase of ferritin concentration parallels a worsening of the clinical status in severely ill patients. This is due to enhanced release by the macrophage system. From this, we consider serum ferritin as an acute-phase protein and a useful marker of the severity of the clinical status. It appears to be useful in predicting the patient's outcome, but is not reliable in evaluating iron stores in stressed patients.     

An enzyme-linked immunoassay for ferritin in human serum and rat plasma and the influence of the iron in serum ferritin on serum iron measurement, during acute hepatitis

To measure human serum ferritin and rat plasma ferritin a non-competitive enzyme-linked immunoassay has been developed using horseradish peroxidase as the enzyme. In this assay it proved necessary to use heated rat plasma to obtain reproducible ferritin values. The heating procedure caused a loss of 38% of the plasma ferritin. Rat plasma ferritin values have been corrected for this loss. The standard deviation, from duplicate normal human and rat samples is 10 ng ferritin/ml serum and 69 ng/ml plasma, respectively. (The mean ferritin concentrations are: in human sera, 82 ng/ml and in rat plasma 762 ng/ml.) Mean recovery of added liver ferritin in the human serum is 104% +/- 4% (+/-S.E.M') and in the rat plasma 101% +/- 3% (+/- S.E.M.). Normal ferritin concentrations varied in the human material between 30 ng/ml and 300 ng/ml serum, and in the rat plasma between 500 ng/ml and 1300 ng/ml. During increased body iron and acute hepatitis the ferritin concentrations, in patients as well as in rats, exceeded the upper limit of the normal values in most cases. During human hepatitis high serum ferritin levels combined with high serum iron levels were measured. The high serum iron concentrations could not be explained by the high serum ferritin concentrations, even if the iron content of the ferritin is supposed to be high.     

Iron reserves in patients with chronic renal insufficiency

Hemorrhage values and the amount of iron entering the body with drugs and blood transfusions were determined in 107 patients with the terminal CRF stage. Of them 59 received regular hemodialyses. The level of serum iron and ferritin as well as iron reserves in the body were investigated at the start and end of the study. In the end a histochemical study of the content of hemosiderin in the bone marrow, liver and spleen was performed. A close interrelationship of iron reserves determined with a modified desferal test and the level of serum ferritin (r = 0.94) was established. The highest iron reserves were revealed in the patients receiving blood transfusions and parenteral iron drugs. Criteria for the assessment of iron reserves in patients with renal failure were determined by means of the modified desferal test and investigation of serum ferritin. Normal ferritin reserves in such patients corresponded to serum ferritin values within the range of 50-400 micrograms/l and indices of the modified desferal test ranging from 0.4 to 2.0/0.5 g of desferal. Of a degree of hemosiderosis one could judge on the basis of a histochemical investigation of tissue hemosiderin only. Iron drugs per os were proposed for the prevention of disorders of iron balance in patients with renal failure.     

Serum ferritin and iron stores during pregnancy

The iron status of two groups of pregnant women was investigated. One group did not receive iron (group B), the other erceived 100 mg iron/day (group A). 1. In all individuals concentrations of hemoglobin, serum iron, transferrin and serum ferritin were determined at regular intervals from the third month until delivery and at 3 months after delivery. The same determinations were performed in cord blood. 2. Changes in iron status appeared to be less in individuals with iron supplement than in those without iron supplement. A fall in Hb, serum iron and serum ferritin is observed in all individuals. 3. Three months after delivery the Hb concentration has generally returned to the normal female value, but the serum ferritin concentration is still very low. 4. The fetus does not discriminate as to the iron status of the mother. In both groups (A and B) cord blood values appeard to be not significantly different.     

Daily doses of 20 mg of elemental iron compensate for iron loss in regular blood donors: a randomized, double-blind, placebo-controlled study

BACKGROUND: A considerable number of regular blood donors develops an iron deficiency, and the exact amount of iron required to compensate for the iron loss from whole-blood donation in males and females is still unknown. STUDY DESIGN AND METHODS: A total of 526 regular blood donors (289 male and 237 female) were randomly assigned to treatment with either 40 mg, 20 mg, or 0 mg per day of elemental iron as ferrous gluconate for a period of 6 months, during which one unit of whole blood was collected on four occasions (males) or three occasions (females). Hemoglobin level, serum ferritin, and soluble transferrin receptor levels were measured before each donation. RESULTS: Daily doses of either 40 mg or 20 mg of elemental iron adequately compensated for iron loss in males, who gave blood at 2-month intervals, but did not result in a positive iron balance or an increase in storage iron as reflected by the logarithm of the ratio of transferrin receptor to ferritin concentration. In females, who donated at 3-month intervals, the same daily doses not only restored the iron balance but also led to an increase in storage iron. The number of gastrointestinal side effects due to iron supplementation (12%) was only slightly higher in both iron groups than in the placebo group. CONCLUSION: The results of this study indicate that 20 mg of elemental iron per day can adequately compensate for iron loss in males and females who donate whole blood up to four (females) or six times per year (males).     

Evaluation of microcytosis

Microcytosis is typically an incidental finding in asymptomatic patients who received a complete blood count for other reasons. The condition is defined as a mean corpuscular volume of less than 80 μm3 (80 fL) in adults. The most common causes of microcytosis are iron deficiency anemia and thalassemia trait. Other diagnoses to consider include anemia of chronic disease, lead toxicity, and sideroblastic anemia. Serum ferritin measurement is the first laboratory test recommended in the evaluation of microcytosis. Low ferritin levels suggest iron deficiency. Once a presumptive diagnosis of iron deficiency anemia has been made, an underlying source for the deficiency should be determined. Iron deficiency anemia in adults is presumed to be caused by blood loss; the most common source of bleeding is the gastrointestinal tract. The possibility of gastrointestinal malignancy must be considered. If the serum ferritin level is not initially low, further evaluation should include total iron-binding capacity, transferrin saturation level, serum iron level, and possibly hemoglobin electrophoresis. Anemia of chronic disease is suggested with low iron levels and decreased total iron-binding capacity. Patients with beta-thalassemia trait usually have elevated levels of hemoglobin A2.     

The characteristics of ferritin from human tissues, serum and blood cells.

1. The properties of ferritin in serum have been compared with those of ferritin from a number of tissues including blood cells. On anion-exchange chromatography with DEAE-Sephadex, the behaviour of human heart ferritin is different from that of liver, kidney or spleen ferritin. Reticulocyte ferritin appears to have similar characteristics to heart ferritin. 2. Serum ferritin from normal subjects and patients with various degrees of iron load, leukaemia or liver disease all have a much lower affinity for the anion-exchange column that any tissue ferritin, suggesting a difference in isoelectric point. The elution point of serum ferritin from patients with acute myeloblastic leukaemia is significantly different from normal. 3. Density gradient centrifugation in sucrose showed that ferritin in leucocyte extracts and partially purified ferritin from the serum of two patients with iron overload behaved as apoferritin rather than the iron-rich protein. 4. The results suggest that ferritin is modified during its entry into the plasma and that even in cases of iron overload the iron content of serum ferritin may be low. The findings are of importance in considering the origin of plasma ferritin, the clearance of ferritin from plasma and its role in iron metabolism.     

Nomogram for individualizing supplementary iron doses during erythropoietin therapy in haemodialysis patients

AIMS: An adequate iron supplement is crucial not only for prompt erythropoiesis but also for the restoration of tissue iron reserves in haemodialysis patients receiving recombinant human erythropoietin (r-HuEPO). An attempt was made to establish a comprehensive nomogram that allows individualization of intravenous (i.v.) iron doses according to patients' body weights, the initial status of tissue iron reserves and desired increases in haemoglobin levels. MATERIALS AND METHODS: Clinical and laboratory data retrieved from 95 haemodialysis patients who received r-HuEPO with or without iron supplements for at least 12 weeks were used to construct the nomogram. It was assumed that the administered iron was either incorporated into newly synthesized haemoglobin and tissue iron reserves or eliminated from the body at a constant rate. Tissue iron reserves of the patients were estimated by serum ferritin levels using van Wyck's equation (Kidney Int., 1989, 35, 712). The rate of iron loss in the patients was estimated by the data obtained from 15 of the above patients who exhibited stable haemoglobin levels but decreases in serum ferritin levels with no iron supplements. The validity of the equation was ascertained by comparing the measured serum ferritin levels at the end of r-HuEPO therapy and those predicted by the nomogram. The proposed nomogram was then validated prospectively in 24 haemodialysis patients to determine whether the nomogram-recommended iron doses would increase both haemoglobin and serum ferritin levels within 12 weeks. RESULTS: The mean (+/-SD) iron loss of haemodialysis patients was calculated to be 10.5 +/- 7.4 mg/week. There was a significant correlation (r=0.77, P < 0.001) between the measured serum ferritin levels, an index of tissue iron reserves, at the end of r-HuEPO therapy and those predicted by the equations used for formulating the nomogram. The prospective study indicated that the nomogram-recommended supplementary iron doses attained haemoglobin and serum ferritin levels of > 95 g/L and >100 microg/L in 79 and 50% of the patients, respectively, within 12 weeks. CONCLUSION: The present nomogram may be useful for individualizing supplementary i.v. iron doses for haemodialysis patients undergoing r-HuEPO therapy.     

Laboratory diagnosis of iron deficiency in a developing country, Pakistan

In developing countries, such as Pakistan, laboratories do not routinely screen for iron deficiency unless the patient presents with symptoms of anaemia. Efforts to prevent the often serious consequences of iron depletion are hampered in developing countries by the expense and impracticality of routinely screening patients using bone marrow examination. Assays for serum iron concentrations, total iron-binding capacity or haemoglobin and examinations of blood films, although more practical, cannot detect the earliest stages of iron deficiency. Serum ferritin appears to be a sensitive, early indicator of iron deficiency and can be easily and relatively inexpensively determined using an immunoassay kit. In the present study, serum ferritin levels were determined using immunoassay and compared to blood films, serum iron levels and total iron-binding capacity values in 300 apparently healthy Pakistanis. In the early stages of iron deficiency, serum ferritin appeared to be a sensitive measure of iron depletion.     

Serum ferritin, blood donation, iron stores and haemochromatosis

Summary. Serum iron and ferritin concentrations were measured in 1,532 regular blood donors from South Wales who were undergoing HLA typing prior to registration on the British Bone Marrow and Platelet Donor Panel. Serum transferrin concentrations were determined for donors with serum iron concentrations > 24 µmol/1. There were 25 donors with transferrin saturations > 50% and 11 with transferrin saturations > 60%. There were five donors with serum ferritin concentrations > 200 µg/1 (women) or > 300 µg/1 (men). Two of the male donors had transferrin saturations > 50% and serum ferritin >300 µg/1 on repeat blood samples and are being treated by venesection. Donors with HLA-A3 did not differ from those without A3 in serum iron or ferritin concentrations. Even in the group of donors who were apparently homozygous for A3 there were neither abnormal serum iron nor ferritin concentrations.
Although it is well established that measurements of transferrin saturation are required to detect homozygous haemochromatosis ( HFE ) in its earlier stages, the number of 'false-positive' results is likely to be unacceptably high for screening blood donors. Serum ferritin assays should identify donors with HFE and iron overload before the onset of liver damage. With two million regular donors and 300,000 new donors each year, a significant proportion of the U.K. population will be screened within 10 years. The assay of serum ferritin identifies donors with low levels of storage iron who are at risk of developing iron-deficiency anaemia. Furthermore, donation frequency may be increased for those donors with higher ferritin concentrations when blood supplies are low.     

Low ferritin levels indicate the need for iron supplementation: strategy to minimize iron-depletion in regular blood donors

Iron deficiency is a common problem in regular blood donors which can be prevented by timely iron supplementation. Consequently, these donors should be supplied with oral iron in good time. We evaluated the need to use ferritin rather than or in addition to haemoglobin to screen iron deficiency in blood donors. To this end, serum ferritin was measured routinely every 10th donation in 632 long-term and 171 first-time donors. Furthermore, donors with ferritin < 15 microg L-1 were supplemented with iron. The supplementation efficiency was assessed by follow-up haemoglobin levels over the course of five donations in blood donors with high donation frequency. Our results showed that ferritin decreases after 10 donations and with the increase of donation frequency. In 26% of regular donors, ferritin levels were < 15 microg L-1 and 12% of them were anaemic due to low haemoglobin. After iron supplementation, haemoglobin was raised rapidly in donors with initially low haemoglobin, and thus donor deferment was never indicated. In conclusion, regular ferritin measurement is a useful indicator for iron depletion in blood donors. Our data suggested the usefulness of ferritin screening in first-time donors and regular donors with low haemoglobin levels within the normal range.     

Evaluation of iron status of Finnish blood donors using serum transferrin receptor

The maximum allowable frequency of blood donations has been set so that donations should not cause anaemia or depletion of iron stores. However, it has not been determined precisely how often blood donations result in depletion of iron stores. In the present study we have evaluated iron status in blood donors using serum ferritin and transferrin receptor (TfR) concentrations. The elevation of serum TfR has been reported to be the most sensitive indicator of depletion of iron stores. On the basis of ferritin values, in men who donate frequently the amount of body iron is reduced to a level very close to that found in women donating blood for the first time. When an elevation of serum TfR above 4.0 mg L-1 was used as a stringent definition of complete iron depletion, it was estimated that 17% of frequently donating women had completely lost their iron stores, while the corresponding value for men was 8%. The fact that a considerable proportion of the female blood frequent donors have completely depleted their iron stores raises the question whether the iron status of female frequent blood donors should be routinely monitored using serum transferrin receptor measurements.