Abnormalities in red blood cell (RBC), mean cellular volume (MCV) are known to occur in non-anemic untreated hyperthyroid and hypothyroid patients. Also in untreated hyperthyroidism, the existence of an elevated total RBC mass, mediated by increased erythropoietin production, have been reported. Reverse findings have been found in untreated hypo- thyroidism. In untreated hyperthyroidism, a slight elevation of the fetal Hb percentage has been found occasionally, raising the question of thyroid hormones effect on globin chain synthesis. Objective: To evaluate effects of thyroid hormones (T3, T4) on the production of both hemoglobin A2, and HbF. 2.Relationships between thyroid hormones and other hematological parameters including {hemoglobin level (Hb g/dL), packed cell volume (PCV%),White blood cells count (WBC×103/μL), red blood cells count (RBC count×106/μL), RBC indices [mean cell hemoglobin (MCH Picogram), mean cell hemoglobin concentration (MCHC g/dL), Mean cell Volume (MCV femtolitre), and Red blood cell distribution width (RDW femtoliter)]}. Subjects, Material& Methods: From November/2006 to May/ 2007, 63 patients referred to endocrinology, and hematology units of Al-khadymia hospital were included in this study and grouped into three groups: - First group included 30 newly diagnosed hyperthyroid patients.
- Second group consisted of 21 hypothyroid patients. - Third group included 12 patients of known cases of thalassemia minor. - Forth group was 28 healthy persons as a control group. For each patient 10 ml of venous blood was obtained, divided into 5ml blood in EDTA plastic tube, half of the sample is used for measurement of hematological parameters by Sysmex (automated hematology analyzer) and blood film staining by Leishman`s stain. The other 2.5ml was used for qualification and quantitation of HbA2, HbF by Variant B-Thalassemia Short program (HPLC). The other 5ml of blood kept in plain plastic tube and used for measurement of TSH, T3, T4 by Mini-Vidas. Statistical analysis had been done using student T test, ANOVA, correlation regression tests taking P value <0.05 as the lowest limit of significance. Results:
HbA2 was significantly higher in hyperthyroid patients than in control group, while HbF was significantly higher in hypothyroid group in comparison with the control. Hemoglobin, PCV, MCH and MCHC were significantly lower in both hyperthyroid and hypothyroid patients, compared with control. Mean cell volume was significantly lower in hyperthyroid, and significantly higher in the hypothyroid group patients in comparison with the control. Red blood cells count was significantly higher in hyperthyroid patients than the control. Lastly, the lymphocytes count was significantly higher in both hyperthyroid and hypothyroid groups of patients. Conclusions: Thyroid hormones have a clear correlation with the expression of hemoglobin A2 percentage in the blood. Its production is enhanced by hyperthyroidism and reduced in hypothyroidism, and thyroid gland disorders are associated with disturbance of hematological parameters.