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A 30-year-old woman was referred for anemia evaluation. A complete blood count (CBC) revealed marked microcytic, hypochromic anemia with mild thrombocytopenia. The main findings of the complete blood count (CBC) test are as follows:

WBC: 7.79*10³/μL, RBC: 4.49*10⁶/μL, Hb: 11.6 g/dL, HCT: 32.7%, MCV:65.6 fL, MCH:23.3 pg, MCHC: 35.5 g/dL, RDW-CV: 16.1%, PLT: 130*10³/μL, MPV:10.1 fL

Peripheral blood smear (PBS) was evaluated and results here are reported based on ICSH recommendations (https://doi.org/10.1111/ijlh.12327). PBS findings confirmed the automated cell-count findings and demonstrated prominent microcytosis (2+) and hypochromia (2+), with mild anisocytosis (1+) and poikilocytosis (1+). Several red blood cell morphological abnormalities were observed, including target cells (1+), ovalocytes (1+), schistocytes (1+), spherocytes (1+), bite cells (1+), and teardrop cells (1+).

Biochemical evaluation showed a normal serum ferritin level (43.9 ng/mL), making iron deficiency an unlikely explanation for the marked microcytosis. Further investigation by capillary hemoglobin electrophoresis revealed a strikingly abnormal hemoglobin distribution, with HbC accounting for 78.5% of total hemoglobin. HbA was markedly reduced (10.5%), while HbA2 and HbF were increased to 5.5% and 4.8%, respectively.

The combination of pronounced microcytosis in the absence of iron deficiency, characteristic red blood cell morphology, and the abnormal hemoglobin profile raised suspicion for a compound hemoglobinopathy involving HbC and β-thalassemia. In particular, the presence of a measurable HbA fraction together with elevated HbA2 and HbF suggested a possible HbC/β⁺-thalassemia phenotype rather than isolated HbC heterozygosity. Genetic testing was therefore recommended for definitive characterization of the underlying β-globin genotype.

This case highlights the importance of integrating peripheral blood morphology with hemoglobin analysis when evaluating unexplained microcytosis. Recognition of the characteristic electrophoretic pattern can provide an important clue to an underlying compound hemoglobinopathy and guide confirmatory molecular testing.

The authors would like to sincerely thank the staff of Aramesh Genetics and Pathobiology Laboratory, Tehran, Iran, for their valuable assistance in the laboratory evaluation and provision of the clinical and morphological images presented in this case.