Prevalence of hypochromia (without microcytosis) vs microcytosis (without hypochromia) in iron deficiency

The usefulness of hypochromia (MCH or = 80 (fl) vs. counterparts with MCV < 80 fl (in the presence of MCH > or = 26 pg). Fifteen per cent of the 201 iron deficient subjects were also shown to have coexisting vitamin B12 deficiency. There was a comparable (16%) prevalence of this haematinic deficiency in the subgroup of 31 iron deficient patients with MCH < 26 pg in the presence of MCH > or = 80 fl.     

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.     

Erythropoiesis during recovery from iron deficiency: normocytes and macrocytes

In 26 patients with severe iron deficiency and microcytic anemia (MCV less than 70 fl), serial red cell size distribution histograms (erythrograms) were taken before and during iron therapy. Initially all patients had a single population of red cells, all microcytes. With the first reticulocytosis after iron therapy, a new population of cells appeared, larger in volume than the original. In 23 of 26 patients the new population of cells was of normal size (82-96 fl). In 3 of 26, the new population was macrocytic (MCV greater than 98 fl). Of these 3, 1 had folate deficiency; after folate was given, normocytes were produced. The other 2, both taking phenytoin and 1 a heavy alcohol using, had persistent macrocytosis despite folate administration. Erythrograms allowed quantitative, rapid evaluation of erythropoietic response to iron repletion. Abnormal macrocytic responses could be identified and seemed to occur with some frequency.     

Red cell nucleotide levels in patients with thalassaemia, iron deficiency, and renal failure

S ummary . Red cell nucleotides, predominantly adenine nucleotides, were measured spectrophotometrically in normal individuals and in patients with iron deficiency, β thalassaemia and renal failure following dialysis or transplantation. There was a significant correlation between the mean red cell haemoglobin (MCH) or the mean cell volume (MCV) and the nucleotide levels in red cells ( P < 0·001). Patients with β thalassaemia did not have increased nucleotide levels compared to red cells having the same MCH or MCV. Patients with renal failure had significantly increased levels of nucleotides compared to normal individuals, and this level remained high after renal dialysis but returned to normal following renal transplantation.     

Hypersegmented neutrophils and vitamin B12 deficiency. Hypersegmentation in B12 deficiency

The sensitivities and specificities of the mean cell volume (MCV), the red cell distribution width (RDW), and blood smear hypersegmentation for B12 deficiency were reviewed in 515 patients whose B12 levels were determined. 61 patients had B12 levels less than 200 pg/ml. 43 patients were defined as B12 deficient (n = 13) or non-B12 deficient (n = 30). Hypersegmentation was more sensitive (91%) than MCV greater than 95 fl (62%) or RDW greater than 15% (54%) in detecting B12 deficiency. The MCV and the RDW should not be relied on when screening for B12 deficiency; examination of the blood smear for hypersegmentation is essential.     

Evaluation of Applying a Combination of Red Cell Indexes and Formulas to Differentiate β-Thalassemia Trait from Iron Deficiency Anemia in the Thai Population

Red cell indexes and formulas have been established as simple, fast, and inexpensive tools to differentiate β-thalassemia (β-thal) trait from iron deficiency anemia. However, none of them showed 100.0% sensitivity and specificity. Moreover, one index may show greater sensitivity and specificity in one population but is ineffective in another population. This study evaluated the diagnostic reliability of a combination of two red cell indexes [red blood cell (RBC) and red blood cell distribution width (RDW)] and nine formulas called ‘11T score’ for differentiation of β-thal trait and iron deficiency anemia in the Thai population. A total of 103 cases, 67 β-thal trait and 36 iron deficiency anemia, Thai subjects with microcytic hypochromic anemia [mean corpuscular volume (MCV) <80.0?fL and mean corpuscular hemoglobin (Hb) (MCH) <27.0?pg] were involved in this retrospective study. The results showed that the 11T score with a cutoff value of 7 was able to discriminate between β-thal trait and iron deficiency anemia with sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and efficiency (EFF) higher than 70.0%. It also had 85.4% of correctly identified cases and the highest value of Youden’s Index (YI) (73.8%) when compared to the 11T score with other cutoff values (5, 6, 8 and 9) and other indexes. Thus, the 11T score with the cutoff value of 7 could be used to differentiate β-thal trait from iron deficiency anemia in the Thai population.     

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%.     

Microcytosis in Hodgkin disease associated with unbalanced globin chain synthesis

A review of 162 patients with Hodgkin disease disclosed 36 with microcytic anemia (mean corpuscular hemoglobin values [MCV] less than 80 fl). Three patients had iron deficiency, and one had beta-thalassemia. Of the remaining 32 patients, 24 had microcytic anemia at the time of diagnosis of Hodgkin disease, and ten, including two patients with this finding initially, developed microcytic anemia in association with recurrence of Hodgkin disease. Seven patients with Hodgkin disease and normal MCV had normal alpha-to-beta-globin chain ratios (1.0 +/- 0.14). Seven patients with Hodgkin disease and MCV less than 80 fl had significantly lower alpha-to-beta chain ratios (0.66 +/- 0.05). Twelve normal controls and four with iron-deficiency anemia and MCV less than 80 fl had normal ratios. Anemia was corrected, and MCV returned to normal in all patients who responded to therapy for Hodgkin disease. In the two patients studied sequentially, abnormal alpha-to-beta-chain ratio was corrected along with the anemia.     

Short Communication:Hemoglobin Machida [β6 (A3) Glu → Gln], a New Abnormal Hemoglobin Discovered in a Japanese Family: Structure,Function and Biosynthesis

This report describes a new abnormal hemoglobin discovered in a 43-year-old Japanese female living in Machida City, Tokyo Capital City, in October 1981. Hematological study of the propositus, who was clinically healthy, showed neither microcytic hypochromic anemia due to iron deficiency, nor hemolytic tendencies, in spite of slightly decreased serum iron and slightly increased reticulocyte count (WBC 4.3 × 10⁹/1, RBC 4.46 × 10¹²/1, Hb 13.6 g/dl, PCV 0.388 1/1, MCV 87 fl, MCH 30.8 pg, MCHC 35.2 g/dl, reticulocyte count 1.4%, total bilirubin 0.3 mg/dl, serum iron 65 μg/dl, TIBC 329 μg/dl). Target cells were not seen on peripheral blood smears. Family study disclosed that her son (10 year old) was a carrier of the same abnormal hemoglobin. He was also apparently healthy and hematologically normal.     

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.     

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.     

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.     

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.     

Clinical utility of the reticulocyte hemoglobin content in the diagnosis of iron deficiency

Determination of the reticulocyte hemoglobin content (CHr) provides an early measure of functional iron deficiency because reticulocytes are the earliest erythrocytes released into blood and circulate for only 1 to 2 days. The CHr in 78 patients undergoing bone marrow examination was measured to assess its clinical utility for the diagnosis of iron deficiency. Twenty-eight patients were iron deficient, based on the lack of stainable iron in the aspirate. The diagnostic power of CHr is limited in patients with high mean cellular volume (MCV) or red cell disorders such as thalassemia. However, when patients with MCV more than 100 fL are excluded, receiver operator curve analysis of CHr, ferritin, transferrin saturation, and MCV demonstrates that CHr has the highest overall sensitivity and specificity of these peripheral blood tests for predicting the absence of bone marrow iron stores.     

The Platelet Count/Mean Corpuscular Hemoglobin Ratio Distinguishes Combined Iron and Vitamin B<Subscript>12</Subscript> Deficiency from Uncomplicated Iron Deficiency

Combined deficiencies of iron and cobalamin are common. The aims of this study were to investigate the significance of the parameters of the complete blood count (CBC) in differentiating microcytic anemia due to pure iron deficiency anemia (IDA) from anemia due to combined deficiencies of vitamin B(12) and iron (IDA-B12). The study was carried out with 122 patients (100 female) who had microcytic red blood cell indices with IDA-B12 and 105 patients (95 female) with IDA. Group IDA-B12 patients had decreased hemoglobin levels, mean corpuscular volumes, mean corpuscular hemoglobin (MCH) levels, and MCH concentrations but had increased platelet counts (PLT). Using these parameters, we developed a PLT/MCH ratio parameter that has high values when IDA is accompanied by cobalamin deficiency. The cutoff value of >12.00, with a 74.6% sensitivity and a 41.9% specificity, appears to be the most convenient value for screening. We advise measuring the levels of cobalamin in patients with IDA associated with a high PLT/MCH ratio.     

Red cell indices as predictors of iron depletion in blood donors

The objective of this study was to investigate whether red cell indices mean cell volume (MCV) and mean cell haemoglobin (MCH) were lower in frequent blood donors and hence, indirectly, able to predict impending iron depletion. Serum ferritin and/or soluble transferrin receptor levels can be used to evaluate iron status but are not practical for routinely screening blood donors prior to donation. Hb, MCV and MCH were measured on venous blood from 886 blood donors using a Sysmex E-5000. Full details were obtained for all donors of each earlier donation over the previous 3 years. MCV and MCH levels were lowest in donors with the highest frequency of previous blood donation. There was a significant negative correlation between MCV and number of donations in males and females and between MCH and number of donations in females, over the 3 year period 1995-97. Similar trends were observed when only the previous year's donations (1997) were considered with all categories showing significant negative correlations and additionally, Hb levels in females showed negative correlation with number of donations in 1997. In conclusion, increased frequency of blood donations is associated with lower MCV and MCH. These red cell indices, or more sophisticated parameters such as percentage hypochromic cells, should be used to monitor early onset of iron depletion in frequent blood donors.     

Three New Hemoglobin Variants with Abnormal Oxygen Affinity: Hb Saratoga Springs [α40(C5)Lys→Asn (α1)], Hb Santa Clara [β97(FG4)His→Asn], and Hb Sparta [β103(G5)Phe→Val]

Abstract

β-Thalassemia (β-thal) and iron deficiency cause most microcytic anemias. Red cell indices and formulas have been established as simple, fast, and inexpensive in discrimination between these two hematological disorders in school children. However, whether these formulas could be applied to diagnose β-thal trait and iron deficiency in adult Thai subjects is unclear. The aim of this study was to examine the diagnostic accuracy of five red cell indices [red blood cell (RBC) counts, mean corpuscular volume (MCV), mean corpuscular hemoglobin (Hb) (MCH), mean corpuscular Hb concentration (MCHC), and red cell distribution width (RDW)] and nine formulas (RDW/RBC, RDW Index, Sirdah, Green and King, Mentzer, England and Fraser, Ehsani, Srivastava and Shine and Lal). Their sensitivity, specificity, positive predictive value (PPV), and negative predictive values (NPV), efficiency, and Youden’s Index were analyzed in 102 β-thal trait and 64 iron deficiency adult Thai subjects. The RDW/RBC formula proved to be the most reliable index as they had 100.0% specificity and PPV and the highest efficiency (94.58%) and Youden’s Index (91.18%), as well as high sensitivity (91.18%) and NPV (87.67%). Therefore, this formula could be used in initial discrimination of β-thal trait from iron deficiency in adult Thai subjects.     

Dyserythropoiesis and ineffective erythropoiesis in Plasmodium vivax malaria

Summary. Nine Thai adults with P. vivax malaria were investigated. Light and electron microscope studies of marrow aspirates revealed morphological evidence of dyserythro-poiesis in six of them, Dyserythropoiesis was most marked in the four most anaemic patients. In these four patients the electron microscope also revealed the presence of erythro-blasts at various stages of degradation within the cytoplasm of macrophages. Neither the dyserythropoiesis nor the ineffective erythropoiesis could be attributed to a deficiency of vitamin B₁₂, folate or iron. The abnormalities of erythropoiesis seemed to result from the P. vivax infection itself. Other bone marrow reactions seen in this infection included macrophage hyperplasia, plasmacytosis and increased eosinophil granulocytopoiesis. Unlike in severe P. falciparum malaria, the microvasculature of the marrow was not obstructed by parasitized red cells.     

The adaptation of Plasmodium falciparum to oxidative stress in G6PD deficient human erythrocytes

It has recently been found that growth of P. falciparum in human G6PD deficient red cells is impaired in vitro; however, the inhibition is overcome after two or three growth cycles. There is evidence to suggest that the parasite can produce its own G6PD enzyme which may compensate for the lack of host enzyme and could account for the resumption of normal growth in G6PD deficient host cells. It is unclear whether the parasite enzyme can enable the host cell to resist oxidative stress as normal cells do. To answer this question, P. falciparum was grown in vitro in: (a) normal red cells, (b) G6PD deficient red cells for one growth cycle only, (c) G6PD deficient cells for a minimum of five cycles. All groups were then challenged with acetylphenylhydrazine (APH) which served as an oxidative stress. Both G6PD (A-) and Mediterranean deficient types were studied. The results show a two-fold increase in resistance to oxidative stress by parasites adapted to G6PD-Mediterranean deficient host cells as compared to unadapted ones, but the parasite-red cell system remains 4 times more sensitive to APH than normal infected cells. In parasitized G6PD (A-) red cells, evidence of adaptation could be seen in the growth curves, but no detectable increase in resistance to APH was found in adapted parasites. It is concluded that the role of the parasite G6PD is not likely to be mainly related to oxidative stress resistance and therefore other functions of this enzyme should be investigated.     

Red blood cell deformability as a predictor of anemia in severe falciparum malaria.

Decreased erythropoiesis and increased clearance of both parasitized and noninfected erythrocytes both contribute to the pathogenesis of anemia in falciparum malaria. Erythrocytes with reduced deformability are more likely to be cleared from the circulation by the spleen, a process that is augmented in acute malaria. Using a laser diffraction technique, we measured red blood cell (RBC) deformability over a range of shear stresses and related this to the severity of anemia in 36 adults with severe falciparum malaria. The RBC deformability at a high shear stress of 30 Pa, similar to that encountered in the splenic sinusoids, showed a significant positive correlation with the nadir in hemoglobin concentration during hospitalization (r = 0.49, P < 0.002). Exclusion of five patients with microcytic anemia strengthened this relationship (r = 0.64, P < 0.001). Reduction in RBC deformability resulted mainly from changes in unparasitized erythrocytes. Reduced deformability of uninfected erythrocytes at high shear stresses and subsequent splenic removal of these cells may be an important contributor to the anemia of severe malaria.