Change in red blood cell distribution width with iron deficiency

Red cell volume distribution width (RDW-CV) was examined as a means of diagnosing iron deficiency. Iron deficiency was classified as iron deficiency anaemia, prelatent or latent iron deficiency in 1648 students. MCV and RDW-CV (mean +/- ISD) in each group were 89 +/- 4 ft, 12.7 +/- 0.7% in normal individuals, 89 +/- 4 fl, 13.2 +/- 0.8% in prelatent deficiency, 86 +/- 6 fl, 14.0 +/- 1.5% in latent deficiency, and 79 +/- 7 fl, 15.6 +/- 1.7% in iron deficiency anaemia, respectively. Although microcytosis was evident only in iron deficiency anaemia, RDW-CV showed larger values concomitant with the development of iron deficiency. The sensitivity of RDW-CV for the diagnosis of iron deficiency anaemia was 77.1%, and for iron deficiency anaemia and latent deficiency 49.2%, the specificity being 90.6%. In countries with a high prevalence of iron deficiency and low thalassaemia, iron deficiency should be screened by RDW-CV determination without serum iron or ferritin measurements.     

Microcytic anaemia in juvenile chronic arthritis

The degrees of anaemia and microcytosis in 100 patients with juvenile chronic arthritis (JCA) were analysed according to the pattern of disease and its activity. Microcytosis was common (40% of patients had a mean corpuscular volume (MCV) of less than 75 fl), sometimes severe (MCV less than 65 fl in 14 patients), and closely correlated with the severity of the anaemia. The degrees of microcytosis and anaemia were both directly related to disease activity as measured by the ESR, and were most severe in cases with the systemic form of JCA. In 50 patients iron status was assessed. The serum iron concentration was directly related to the MCV, whereas the serum ferritin was inversely related to MCV and haemoglobin concentration and directly related to the ESR. Bone marrow iron stores were normal or increased in 6 patients with severe microcytic anaemia. These data suggest that the anaemia of JCA is typically microcytic, and that this microcytosis is associated with the disturbance of iron metabolism seen in the 'anaemia of chronic disorders' rather than overall depletion of body iron.     

Combined use of erythrocyte zinc protoporphyrin and mean corpuscular volume in differentiation of thalassemia from iron deficiency anemia

Abstract: In a retrospective study the diagnostic value of erythrocyte zinc protoporphyrin (ZPP) measurement as a means of distinguishing iron deficiency anemia from thalassemia syndromes in patients with microcytosis was explored. ZPP values were increased in all patients with iron deficiency and in part of the patients with thalassemia. The combined measurement of erythrocyte mean corpuscular volume (MCV) and ZPP resulted in a correct classification of patients with iron deficiency and with thalassemia in more than 95%. The predictive value of this method is better than the results obtained by using formulae derived from red cell indices. In population screening programs for thalassemia syndromes, in which MCV determination is used as the initial test, the ZPP test is recommended as a second test, in order to discriminate between patients with microcytosis due to iron deficiency and patients with microcytosis due to thalassemia syndromes.     

Diagnostic clues to megaloblastic anaemia without macrocytosis

Masking of the macrocytic expression of megaloblastic anaemia (MA) by coexisting thalassaemia, iron deficiency and chronic illness has been widely reported. We described the haematological and clinical features of 20 Chinese patients with MA presenting with mean corpuscular volume (MCV) < or =99 fl, and analysed the steps leading to the final diagnosis of MA with concomitant thalassaemia trait (n = 11), thalassaemia trait and iron deficiency (n = 3), iron deficiency (n = 4) and chronic illness (n = 2). We also compared the haematological characteristics of this group of patients with a group of normocytic anaemic patients without vitamin B(12)/folate deficiency, and identified certain laboratory information useful for differentiating the two groups. Statistically significant parameters included the mean values of haemoglobin, MCV, red cell distribution width (RDW), reticulocyte index, platelet count and serum bilirubin. All provided clues to maturation disorders within the marrow. A decision flowchart for the diagnosis of MA without macrocytosis was proposed. In the studied population, by using the parameters of haemoglobin <10 g/dl, MCV 80-99 fl, RDW > or = 16% and reticulocyte index < or = 2% as indicators, there was a 58% chance that a patient had MA without macrocytosis if he/she had all the four indicators, and a 2.2% chance of having it if he/she did not have these indicators. We emphasized the importance of including peripheral blood smear examination in the diagnostic procedures for such patients, as well as the importance of paying attention to patients' medical history, racial background and previous MCV value.     

Microcytosis, Anisocytosis and the Red Cell Indices in Iron Deficiency

S ummary . Red cell volume distribution curves have been used to measure micro-cytosis and anisocytosis in normal subjects, blood donors and patients with iron deficiency anaemia. These measurements were more sensitive than the conventional red cell indices for detecting blood donors with a low transferrin saturation. Three stages are suggested as iron deficiency progressively interferes with haemopoietic function. Anisocytosis and an increased percentage of microcytic cells are the first haematological abnormalities to occur and at this stage haemoglobin concentration is usually normal and transferrin saturation less than 32%. At the second stage the MCV and MCH decline, haemoglobin concentration is generally sub-normal, though not below 9 g/dl, and transferrin saturation is usually below 16%. The final stage of iron deficiency is associated with a low MCHC, a haemoglobin concentration below 9 g/dl and a transferrin saturation of less than 16%.     

Incidence of iron-deficiency anaemia in infants in a prospective study in Jordan

A high prevalence of iron-deficiency anaemia has been reported in Jordanian infants. A prospective study of infants in downtown Amman examined the relationship between anaemia in pregnancy and iron deficiency in infancy. The iron status of infants born to 107 anaemic (Hb < 11 g/dl) and 125 non-anaemic mothers was reviewed at 3, 6, 9 and 12 months. Indicators to define iron-deficiency anaemia were Hb < 11 g/dl and either plasma ferritin < 12 microg/l or zinc protoporphyrin (ZPP) > 35 microg/dl whole blood. Haemoglobin electrophoresis excluded haemoglobinopathy. There was 72% iron-deficiency anaemia throughout the year, significantly higher in infants born to anaemic mothers (81%; n = 91) compared with controls (65%; n = 112). At 12 months, 72% of the infants tested (n = 195) were anaemic. While 57% were identified as iron-deficient by research criteria of either ferritin or ZPP, only 37% were identified by ferritin alone, 40% by ZPP alone and 29% if both ferritin and ZPP were required to meet criteria. Most infant anaemia was identified as due to iron deficiency, supporting contextual setting as assisting diagnosis: infants in developing countries are recognised as vulnerable to iron deficiency. Using multiple criteria, more cases were identified when either ferritin or ZPP were abnormal than when one alone, or both parameters were required to meet research criteria.     

Quantitative anisocytosis as a discriminant between iron deficiency and thalassemia minor

The coefficient of variation (CV) of red cell size, as measured by electronic red cell sizing (erythrography), was less than 14.0% in 20 normal subjects. In 22 of 25 patients with beta-thalassemia minor and microcytosis (mean corpuscular volume [MCV] less than 70 fl), CV was less than 14.0%; in the other 3, CV was 14.0%--14.9%. In 53 patients with iron deficiency anemia and MCV less than 70 fl, CV always was greater than 14.0%. In 7 patients with alpha-thalassemia minor and MCV less than 70 fl, CV was less than 14.0% in all 7. Among patients with microcytosis, erythrography appears to be an excellent technique for rapidly distinguishing between iron deficiency and alpha or beta thalassemia minor.     

Alpha Thalassaemia in American Blacks: a Study of a Family with Five Cases of Haemoglobin H Disease

Five cases of HbH disease were discovered in a large family of American Blacks. Anaemia was mild with PCV ranging from 0.275 to 0.405. The amount of HbH was 2--6%. Studies of haemoglobin synthesis in peripheral blood reticulocytes demonstrated marked deficits in alpha globin production with an average alpha/beta ratio of 0.31 (range 0.22--0.36). Eighteen additional family members had evidence of thalassaemia trait and were provisionally classified as either alpha-thal-1 (average MCV 65.2 fl; range 59--70) or alpha-thal-2 (average MCV 79.6 fl; range 74--88). A subject with altha-thal-1 trait had an alpha/beta ratio of 0.56; the average for five cases of alpha-thal-2 was 0.73. One other family member was thought to be homozygous for alpha-thal-2 trait and exhibited an MCV of 65 fl with an alpha/beta ratio of 0.5. These data reconfirm that in Blacks with alpha thalassaemia the proportion of HbH is lower and the severity of anaemia is less than in certain other racial groups, e.g. Southeast Asians. However, the degree of hypochromia and microcytosis and the imbalance in alpha and beta globin synthesis appear to be similar in Blacks and other races. These results suggest that the milder clinical course of HbH disease in Blacks is not a result of greater alpha globin production in that population of thalassaemics.     

Evaluation of clinical pallor in the identification and treatment of children with moderate and severe anaemia

BACKGROUND: Anaemia from malaria is a common problem in developing countries. Blood transfusion in developing countries is available in few hospitals. Children who are severely anaemic and may require urgent blood transfusion usually present to peripheral first-level health facilities from where they must be referred to hospitals. Since most peripheral facilities do not determine haemoglobin levels, the decision on referral has to be made on clinical grounds. OBJECTIVES: To evaluate the sensitivity and specificity of clinical pallor of the palms, nailbeds, conjunctivae, buccal mucosa or tongue against haemoglobin values and their reproducibility among health workers. METHODS: A total of 2540 children 2 months to 5 years of age presenting to a rural health centre in Ethiopia were enrolled. Clinically detected pallor was compared with measured blood haemoglobin concentrations. RESULTS: Any anaemia (haemoglobin < 11 g/dl) was found in 61% of the children. Severe anaemia (haemoglobin < 5 g/dl) was found in 4%. The presence of any pallor clinically correlated with moderate anaemia (haemoglobin level < 8 g/dl) could be detected with a sensitivity of 95% and a specificity of 64-68% when the palm and nailbeds were used and a sensitivity of 84% and a specificity of 81% when the conjunctivae were used. Severe anaemia was detected clinically as severe pallor in 50-56% of cases (with a specificity of 95-96%). Agreement between physicians was highest for conjunctivae and nailbed pallor (87%) and lowest for palm pallor (73%). Using multivariate analysis, identification of a systolic ejection murmur or altered sensorium, the presence of splenomegaly or malarial parasitaemia were independently predictive of severe and moderately severe anaemia. CONCLUSIONS: Moderate and severe anaemia can be identified clinically in most cases for treatment and referral purposes. A systolic ejection murmur, altered sensorium, the presence of splenomegaly or malarial parasitaemia may be used as additional tools in considering urgent referral for blood transfusion.     

Regression of extramedullary haemopoiesis and augmentation of fetal haemoglobin concentration during hydroxyurea therapy in β thalassaemia

Hydroxyurea increases fetal haemoglobin in many patients with sickle cell anaemia, but its effectiveness in thalassaemia appears to be less consistent. We describe the response to hydroxyurea in an adult male with homozygous β thalassaemia, symptomatic paraspinal extramedullary haemopoiesis, bone pain, and progressive tissue iron loading. Prior to therapy with hydroxyurea the circulating haemoglobin (Hb) concentration was 7.0 g/dl and absolute fetal haemoglobin concentration was 5.0 g/dl. Administration of sodium phenylbutyrate had induced no increase in either parameter. Subsequent therapy with hydroxyurea was associated with increases in total haemoglobin to 9.0 g/dl, and in fetal haemoglobin to 7.6 g/dl. Ineffective erythropoiesis was reduced and extramedullary haemopoiesis regressed during therapy.     

Alpha thalassaemia in Zambian newborn

The umbilical cord blood from 109 consecutive Zambian neonates (excluding those found to be anti-HIV positive) were analysed for haemoglobin (Hb) Bart's and for alpha thalassaemia by restriction endonuclease analysis. This showed that 52.3% had the genotype alpha alpha/alpha alpha, 38.5% had -alpha 3.7/alpha alpha, 7.3% had -alpha 3.7/-alpha 3.7 and 1.8% had alpha alpha alpha/alpha alpha. The alpha thalassaemia gene (-alpha) frequency was 0.27. There were no apparent differences in gene frequency between six major Zambian ethnic groups. Detection of Hb Bart's identified all alpha-thalassaemia homozygotes (-alpha/-alpha), but fewer than 10% of heterozygotes (-alpha/alpha alpha). alpha-thalassaemia was associated with slight but significant anaemia and microcytosis.     

Discriminant analysis of iron deficiency anaemia and heterozygous thalassaemia traits: a 3-dimensional selection of red cell indices.

The two main causes of microcytic and hypochromic anaemia are iron deficiency and thalassaemia traits. Discriminant analysis based on a simple combination of classical red cell indices have been used to differentiate between iron deficiency anaemia and thalassaemia with varying degree of accuracy. Two new indices are now available from modern cell counters: red cell distribution width (RDW) and haemoglobin concentration distribution (HDW). Our discriminant analysis suggests that RBC, MCHC and RDW contribute significantly to the differentiation between iron deficiency anaemia and thalassaemia in both healthy donors and hospital-patient groups. In the discriminating process, previous workers have overlooked the heterogeneity of anaemia between anaemic groups as well as biological differences in MCV and MCH among the alpha and beta thalassaemia subjects. This study took into account of these biases and proved, for the first time, that differentiation between iron deficiency and thalassaemia by discriminant analysis was clinically reliable and not significantly biased by the severity of anaemia. The diagnostic accuracy of discriminant analysis was confirmed retrospectively by the reallocation algorithm using the jack-knife principle and prospectively by testing the discriminant functions on independent new samples. Selection of the red cell indices contributing to the discrimination of microcytic hypochromic anaemia was based on biological and statistical considerations. The clear separation of red cell index data of iron deficiency anaemia and thalassaemia traits was shown 3-dimensionally by surface plots.     

The Haematological Effects of Glucose-6-Phosphate Dehydrogenase Deficiency and Thalassaemia Trait: Interaction between the Two Genes at the Phenotype Level

The haematological effects of glucose-6-phosphate dehydrogenase (G6PD) deficiency and thalassaemia trait were evaluated in a field study of 317 individuals in an isolated Sardinian village, where both traits were present at high frequency. G6PD deficiency was diagnosed with rigid genetic criteria. Thalassaemia trait was diagnosed on the basis of abnormal osmotic fragility.
Complete G6PD deficiency resulted in mild anaemia with macrocytosis, a consequence of mild chronic haemolysis. Partial G6PD deficiency had a similar, but less marked effect. Thalassaemia trait resulted in mild anaemia, with marked microcytosis and moderate hypochromia.
The haematological effects of the combination of both traits were equal to the sum of the independent effect of each. The G6PD activity of the individual red cells was similar in thalassaemic and normal individuals. Because of the microcytosis, the G6PD activity per gram of haemoglobin per unit volume of red cells or of whole blood appeared to be elevated in thalassaemia trait.     

Discriminant analysis of iron deficiency anaemia and heterozygous thalassaemia traits: a 3-dimensional selection of red cell indices

Summary The two main causes of microcytic and hypochromic anaemia are iron deficiency and thalassaemia traits. Discriminant analysis based on a simple combination of classical red cell indices have been used to differentiate between iron deficiency anaemia and thalassaemia with varying degree of accuracy. Two new indices are now available from modern cell counters: red cell distribution width (RDW) and haemoglobin concentration distribution (HDW). Our discriminant analysis suggests that RBC, MCHC and RDW contribute significantly to the differentiation between iron deficiency anaemia and thalassaemia in both healthy donors and hospital-patient groups. In the discriminating process, previous workers have overlooked the heterogeneity of anaemia between anaemic groups as well as biological differences in MCV and MCH among the α and β thalassaemia subjects. This study took into account of these biases and proved, for the first time, that differentiation between iron deficiency and thalassaemia by discriminant analysis was clinically reliable and not significantly biased by the severity of anaemia. The diagnostic accuracy of discriminant analysis was confirmed retrospectively by the reallocation algorithm using the jack-knife principle and prospectively by testing the discriminant functions on independent new samples. Selection of the red cell indices contributing to the discrimination of microcytic hypochromic anaemia was based on biological and statistical considerations. The clear separation of red cell index data of iron deficiency anaemia and thalassaemia traits was shown 3-dimensionally by surface plots.     

New indices from the H*2 analyser improve differentiation between heterozygous β or δβ thalassaemia and iron-deficiency anaemia

Summary The two main causes of microcytic and hypochromic anaemia are iron deficiency (IDA) and thalassaemia (THAL) traits. In the Mediterranean area there is a high prevalence of β and δ-β THAL minor. The differentiation between these causes of microcytosis can be significantly improved with two new indices, percentage of microcytes (%Mi) and percentage of hypochromic red blood cells (%Hy), and the direct determination of MCHC, provided by the technological advances of the H*2 analyser. Our discriminant analysis, based on the minimization of Wilk's lambda (A) criterion, was used to select the best predictive variables to differentiate between IDA and THAL and has resulted in the highest diagnostic efficiency published to date. The discriminant function obtained is a simple linear combination of the following variables: D = 1.145 RBC-0.174 MCV+0.091 MCHC+0.787 √(%Hy/%Mi)-22.119. The overall correct classification was 97.6% on the training sample (79 THAL and 90 IDA) and 96.7% on a validation sample of microcytic patients (72 THAL and 80 IDA). The sensitivity and diagnostic specificity were 97.5% and 97.8%, respectively, for the training sample, and 95.8% and 97.5% for the control group.     

Iron deficiency anaemia in hospitalised patients: value of various laboratory parameters. Differentiation between IDA and ACD.

BACKGROUND: for the diagnostic evaluation of microcytic or normocytic anaemia in a heterogeneous group of patients, the value of newer parameters, such as zinc protoporphyrin (ZPP), plasma transferrin receptor (PtrfR) and PtrfR/ferritin ratio is not clear. We have performed a prospective study to determine the predictive value of these parameters and ferritin, for diagnosing iron deficiency anaemia (IDA). METHODS: sixty-two patients with Hb<8.2 (men) or <7.0 (women) and mean cell volume (MCV)<96 fl were included. Exclusion criteria were: known haematological disease, pregnancy, bone marrow suppression or iron therapy within the previous 7 days. Bone marrow examination was used as a golden standard to discriminate between IDA and non-IDA. RESULTS: twenty-four patients had depleted iron stores. We found that the reticulocyte response on iron supplementation correlated well with the iron-status of the bone marrow. Univariate analysis showed that ferritin, PtrfR/ferritin ratio, ZPP and PtrfR have significant predictive values for differentiating IDA from non-IDA. Interestingly, multivariate analysis revealed that ferritin was the only significant, independent predictor of IDA, with a cut-off point of 32 microg/l (sensitivity 79.2%, specificity 96.9%). CONCLUSIONS: the low sensitivity and specificity of ZPP, PtrfR and PtrfR/ferritin ratio render them insufficient to be used as a single 'best' test for the identification IDA in a non-selected group of anaemic patients and do not even add to the prediction if the value of ferritin is known.     

The measurement of erythrocyte zinc protoporphyrin/heme ratio in various anemias in childhood]

The measurement of erythrocyte zinc protoporphyrin (ZPP) with a hematofluorometer is known to be a simple and cost-effective method to screen iron deficiency and lead poisoning. We measured ZPP on blood samples from 201 children suffering from various diseases, which revealed that ZPP has better sensitivity and specificity for identifying iron deficiency than serum ferritin and percent transferrin saturation. ZPP levels in various anemias were also measured. ZPP rose markedly (> 200 mumol/mol heme) in untreated iron deficiency anemia and returned to normal in 3-4 months since the initiation of iron therapy. Moderate elevation of ZPP was observed in acute leukemia (at onset and during induction therapy), MDS, aplastic anemia and some other anemic conditions. These findings suggest that erythrocyte ferrochelatase may be unexpectedly affected in anemias even except lead poisoning.     

The value of the erythrocyte indices as a screening procedure in predicting nutritional deficiencies

The results of a large number of nutritional screen requests (n = 871) were compared with corresponding values of erythrocyte indices considered predictive of nutritional deficiencies to determine if such indices could be used in a prospective screening procedure to restrict the number of serum vitamin B12, folate, and ferritin assays. Low mean cell haemoglobins (MCH less than 27 pg) were found to be superior to low mean cell volumes (MCV less than 77 fl), in predicting low serum ferritin values. The occurrence of deficient ferritin values was 90% when the MCH was very low (MCH less than 23 pg). Vitamin B12 or folate deficiency could not be predicted from the MCV. A normal MCV was found in more than 55% of vitamin B12 deficient samples and some 30% of serum B12 deficients (less than 150 micrograms/l) showed no evidence of anaemia (Hb greater than 12 gm/dl) or macrocytosis (MCV less than 100 fl). It would not seem appropriate to use erythrocyte indices alone as a method of selecting samples for further investigation of folate or vitamin B12 status.     

Recognition of pallor associated with severe anaemia by primary caregivers in western Kenya

OBJECTIVES: To explore which pallor signs and symptoms of severe anaemia could be recognized by primary caregivers following minimal instructions. METHODS: Data from three community-based cross-sectional surveys were used. Test characteristics to predict haemoglobin (Hb) concentrations < 5 and < 7 g/dl were compared for different combinations of pallor signs (eyelid, tongue, palmar and nailbed) and symptoms. RESULTS: Pallor signs and haemoglobin levels were available for 3782 children under 5 years of age from 2609 households. Comparisons of the sensitivity and specificity at a range of haemoglobin cut-offs showed that Hb < 5 g/dl was associated with the greatest combined sensitivity and specificity for pallor at any anatomical site (sensitivity = 75.6%, specificity = 63.0%, Youden index = 38.6). Higher or lower haemoglobin cut-offs resulted in more children being misclassified. Similar results were obtained for all individual pallor sites. Combining a history of soil eating with pallor at any site improved the sensitivity (87.8%) to detect Hb < 5 g/dl with a smaller reduction in specificity (53.3%; Youden index 41.1). Other combinations including respiratory signs or poor feeding resulted in lower accuracy. CONCLUSION: Primary caregivers can recognize severe anaemia (Hb < 5 g/dl) in their children, but only with moderate accuracy. Soil eating should be considered as an additional indicator of severe anaemia. The effect of training caretakers to improve recognition of severe anaemia and care-seeking behaviour at the household level should be assessed in prospective community-based studies.     

Causes of microcytic anaemia and evaluation of conventional laboratory parameters in the differentiation of erythrocytic microcytosis in blood donors candidates*

ABSTRACT

Context and Objective: Microcytic anaemia results from defective synthesis of haemoglobin in the erythroid precursors, causing a reduction in its mean corpuscular volume (MCV). The most common causes of microcytosis, without the increase in HbA₂ levels, are iron deficiency anaemia (IDA) and α-thalassemia. The aim of this study was to identify the causes of microcytic anaemia and evaluate the haematological parameters from blood donors deemed ineligible (due to the low haematocrit level) that would differentiate the IDA and α-thal, whether isolated or in association.

Methods: Genomic DNA was submitted to the polymerase chain reaction multiplex for the diagnosis of the most common allele deletions of α-thal and erythrogram and in order to verify haematological parameters. Iron deficiency (ID) was determined through the measurement of serum ferritin.

Results: Of the 204 samples, 82 (40.2%) were identified with ID, 24 (17.8%) with α-thal and 10 (4.9%) with ID associated with α-thal. In the α-thal with ID group haemoglobin (Hb), MCV, mean corpuscular Hb concentration (MCHC) and mean corpuscular Hb (MCH) values were significantly lower compared to the isolated α-thal. In the group with ID Hb, MCV, MCHC and MCH values were significantly lower compared to those with isolated α-thal. The α-thal with ID group, showed Hb, MCV, MCHC and MCH significantly reduced when compared to those with IDA.

Conclusions: This study showed that the values of haematological parameters, especially haematocrit, Hb, MCV, MCH, MCHC and red blood cell distribution width (RDW), are lower in patients with IDA, especially when associated with α-thal and therefore it may be useful to discriminate between the different types of microcytic anaemia.