Utility of Red Blood Cell Parameters and Indices of Iron Homeostasis in Evaluation of Microcytosis without Anemia or with Mild Anemia: A Diagnostic Accuracy Study

Introduction Asymptomatic microcytosis may be a prelude to microcytic hypochromic anemia of varied causes. Evaluation of red cell indices may help delineate cases needing further investigation like hemoglobin high-performance liquid chromatography (Hb-HPLC). In addition, markers of iron homeostasis will help confirm iron-deficient erythropoiesis (IDE)/iron deficiency anemia (IDA).Materials and Methods This was a single institutional hospital-based study over a period of 18 months. The sample size was 60, which include all age groups, males and females, and values of mean corpuscular volume (MCV) < 80 fL, Hb > 10g/dL were taken as the inclusion criteria. Various derived red cell indices, Hb-HPLC, and iron parameters were assessed. HbHPLC and serum ferritin with transferrin saturation (TSAT) values were taken as the gold standard for diagnosis of hemoglobinopathies/thalassemia trait and IDA/IDE, respectively.Results Out of 60 samples, 24 (40%) and 36 (60%) had abnormal and normal proportion of Hb variants, respectively. In total, seven indices were evaluated, which included Mentzer's index, red cell distribution width index, Ehsani's index, Sirdah's formula, Matos-Carvalho index, Shine and Lal index, and Sehgal's index. The Shine and Lal index showed better sensitivity (89%) and specificity (73%) for diagnosing pure thalassemia trait. The Sirdah index showed better sensitivity (78%) and specificity (42%) in diagnosing IDE/IDA. Ferritin showed better sensitivity (74%) and specificity (84%) in diagnosing pure IDA and TSAT showed better results in diagnosing IDA/IDE.Conclusion The Shine and Lal index and Mentzer index can be used as screening tools and help detect subjects who require appropriate follow-up with confirmation by HbHPLC. Serum ferritin remains the gold standard for diagnosis of IDA.