M/H ratio for the differential diagnosis of microcytic anemia

Elevated hemoglobin A2 as a marker for β-thalassemia trait in pregnant women

β-thalassemia is one of the most prevalent inherited hemoglobin disorders. Compound heterozygotes or homozygous mutations of the β-globin chain gene account for severe cases of β-thalassemia that require lifelong transfusion, and make it necessary to identify β-thalassemia carries for prenatal diagnosis. The increase in hemoglobin A2 (HbA2) level is the most significant parameter in the identification of β-thalassemia carriers. HbA2, composing of two α chains and two δ chains, is a minor component of the hemoglobin present in normal adult red blood cells, accounting for about 2.5% of the total hemoglobin in healthy individuals. However, HbA2 level is also elevated in some pregnant women. This study aimed to evaluate the value of HbA2 level in the screening of pregnant women with β-thalassemia trait. Pregnant and non-pregnant women were randomly recruited who attended the prenatal care or diagnosis at our hospital located in Guangdong, a province in South China. Hemoglobin capillary electrophoresis was performed on high performance liquid chromatography to measure HbA2 levels in blood. The β-globin gene mutations were detected by the PCR-reverse dot-blot assay, and some were verified by direct sequencing. Pregnant women (n = 96) and non-pregnant women (n = 114) with normal HbA2 level (< 3.5%) had no β-thalassemia mutation. In contrast, pregnant women (n = 55) and non-pregnant women (n = 85) with elevated HbA2 level (≥ 3.5%) are β-thalassemia carriers. In conclusion, HbA2 level is a good marker for screening β-thalassemia trait in pregnant women in South China population.

Erythrocyte and reticulocyte parameters in iron deficiency and thalassemia

INTRODUCTION

Red blood cells (RBCs) extended parameters or erythrocyte subsets are now reported by the new Sysmex XE 5000 analyzer. This study was aimed at establishing a characteristic analytical feature, including the new erythrocyte and reticulocyte parameters, in case of thalassemia trait and iron deficiency (IDA).

METHODS

Ninety healthy individuals, 136 β-thalassemia carriers, 121 mild IDA, and 126 severe IDA patients were analyzed.

RESULTS

The values obtained for the RBC extended parameters were significantly different (P<0.0001) in the groups; the only exception was %Hypo-He in the case of mild IDA and thalassemia (P=0.6226). %Hypo-He was considerably greater in severe IDA (23.4%) than in mild cases (12.4%), P<0.0001. %MicroR was more increased in thalassemia (38.6 %) than in the mild IDA (16.5%, P<0.001) and in severe IDA (21.6%, P<0.001). Immature reticulocyte fraction (IRF) mean values in the groups were statistically different; the thalassemia group had an intermediate value (8.7%) between healthy (4.4%) and IDA (16.7 and 12.9%).

CONCLUSIONS

Erythrocytosis and severe microcytosis, together with a high percentage of microcytes and a moderate increase in IRF, is the profile of β-thalassemia carriers, whereas anisocytosis and the hypochromic subset correlates with the severity of the anemia in iron-deficient patients.

Evaluation of indices in differentiation between iron deficiency anemia and beta-thalassemia trait for Chinese children

Iron deficiency anemia (IDA) and beta-thalassemia trait (beta-TT) are the most common microcytic anemia. Kinds of discrimination indices have been established as simple, fast, and inexpensive means since 1970s. This study evaluates the validity of 12 indices in differentiation between IDA and beta-TT for Chinese children. The 12 discrimination indices were red blood cell (RBC) count, RBC distribution width, Mentzer Index, Green and King Index, RBC distribution width Index, England and Fraser Index, Shine and Lal Index, Srivastava Index, Ricerca Index, Ehsani Index, Sirdah Index, and Huber-Herklotz-Index. A total of 300 children (beta-TT, n=127 and IDA, n=173) were enrolled in the study. We calculated the sensitivity and specificity, positive and negative predictive values, and Youden's index for each index. We also established new cut-off values by receiver operating characteristic curves. Green and King Index showed the highest reliability, as it had the largest area under the curve (AUC=0.947), whereas Srivastava Index and Shine and Lal Index showed the lowest reliability (AUC=0.679 and 0.532, respectively). We concluded Green and King Index, Ricerca Index, and England and Fraser Index could be used in discrimination between IDA and beta-TT in Chinese children.