Correlation of thyroid stimulating hormone levels and hematological parameters among euthyroids, hypothyroids and hyperthyroids

Pushparaj T .


BACKGROUND Thyroid hormones have a crucial role in metabolism and proliferation of blood cells. Thyroid dysfunction induces different effects on blood cells such as anemia, erythrocytosis and alters RBC indices. This study was attempted to evaluate the effect of hypothyroidism and hyperthyroidism on Hemoglobin (Hb), Hematocrit (HCT) and Mean Corpuscular Volume (MCV). METHODS This observational study was performed on 90 women visiting endocrinology department. Thyroid stimulating hormone (TSH) levels of the subjects was determined and according to TSH ranges, patients were divided into euthyroids (TSH - 0.30-5.50IUmL), hyperthyroids (TSH 0.30IUmL) and hypothyroids (TSH 5.50IUmL). EDTA samples were subjected for complete blood count in which Hb, HCT and MCV were taken for this study. Anemia was defined by hemoglobin level 12 gm in women, further classified as microcytic, normocytic, or macrocytic in the presence of MCV values of less than or equal to 80 fL, 80 to 95fL, and greater than or equal to 95 fL respectively. The results were analyzed by SPSS software using independent student t test and pvalue 0.05 was considered to be statistically significant. RESULTS There was statistically significant difference in Hb, MCV and HCT when euthyroids were compared with hypothyroids and hyperthyroids. MCV values were significantly decreased in hyperthyroidism while significantly increased in hypothyroidism. Hb and HCT were significantly decreased in both hyperthyroidism and hypothyroidism compared to euthyroids. CONCLUSION Thyroid hormones have a significant influence on erythropoiesis. Thyroid dysfunction produces anemia, mostly microcytic anemia in hyperthyroids and macrocytic in hypothyroids.All the patients with hypothyroidism and hyperthyroidism should be periodically evaluated for hematological changes and the patients with unknown hematological dysfunctions must be evaluated for thyroid function tests.

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