Hematological Parameters Extended for Automated Analyzer

The quantification of the percentages of microcytic and hypochromic erythrocytes has proved clinically useful in the differential diagnosis of anemia.

Based on classical hematological parameters, subjects with iron deficiency anemia (IDA) are inappropriately differentiated from subjects with anemia owing to thalassemia or chronic disease.

A study conducted at the Hospital Galdakao-Usansolo, (Galdakao, Spain), aimed to establish characteristic analytical features, including the new erythrocyte and reticulocyte parameters, in case of thalassemia trait and IDA. The study population included 90 healthy individuals, 136 β-thalassemia carriers, 121 with mild IDA, and 126 with severe IDA. The scientists used the Sysmex XE 5000, which utilizes the flow fluorescence-cytometry technology, enables independent measurement of the volume and hemoglobin (Hb) content of individual red cells (RBC). Derived from this technology, four new RBCs extended parameters, erythrocyte subsets, are now reported for this analyzer.

When using the Sysmex XE 5000 analyzer, (Sysmex Corporation, Kobe, Japan; www.sysmex.com), the percentages of erythrocyte subsets can be calculated and the new parameters, such percentage of microcytic red cells (%Micro R) and percentage of macrocytic red cells (%Macro R) can be obtained. In the reticulocyte channel, blood cells are stained by a polymethine dye specific for ribonucleic acid, (RNA) /DNA, and analyzed by flow cytometry using a semiconductor laser. A bidimensional distribution of forward scattered light and fluorescence is presented as a scattergram, indicating mature red cells and reticulocytes. Forward scatter correlates with reticulocyte hemoglobin content (Ret He) and erythrocyte hemoglobin content (RBC He).

The results of the study indicate that although the differences between the three groups of anemic patients were statistically significant, the central 95th percentile ranges showed considerable overlap for most hematological parameters including absolute reticulocyte count. The values obtained for the RBC extended parameters were significantly different in the groups. The %Micro R was more increased in thalassemia (38.6 %) than in the mild IDA (16.5%), and in severe IDA (21.6%). Immature reticulocyte fraction (IRF) mean values in the groups were statistically different as the thalassemia group had an intermediate value of 8.7%, which was between the healthy value of 4.4% and IDA values ranging from 12.9% to 16.7%.

The authors concluded the 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. The study was published online on May 12, 2011, in Journal of Clinical Laboratory Analysis.

Related Links:
Hospital Galdakao-Usansolo
Sysmex Corporation