ERYTHROCYTE size and HEMOGLOBIN content or concentration, usually derived from ERYTHROCYTE COUNT; BLOOD hemoglobin concentration; and HEMATOCRIT. The indices include the mean corpuscular volume (MCV), the mean corpuscular hemoglobin (MCH), and the mean corpuscular hemoglobin concentration (MCHC). The trait is erythrocyte indices (EFO_0004306). Also known as: RBC count, erythrocyte index, erythrocyte indexes, erythrocyte size determination, red cell index, red cell indices.