Normochromic Information and Courses from MediaLab, Inc.

Beta Thalassemia Silent Carrier Beta Thalassemia Minor Beta Thalassemia Intermedia Beta Thalassemia Major Delta-Beta Thalassemia Anemia Absent Mild to absent Moderate Severe Mild Red blood cell (RBC) count Normal Increased Decreased to normal Decreased Decreased to normal Hemoglobin(Hb) Normal Decreased to normal (10 - 12 g/dL) Decreased (7 - 10 g/dL) Marked decrease (<7 g/dL) Decreased to normal (8 - 13 g/dL) Mean corpuscular volume (MCV) Slight to no decrease Marked decrease Marked decrease Marked decrease May be slightly decreased Mean corpuscular hemoglobin concentration (MCHC) Slight to no decrease Marked decrease Marked decrease Marked decrease May be slightly decreased Red blood cell distribution width (RDW) Normal Normal to slightly increased Increased Increased Normal RBC morphology Normal Marked hypochromia and microcytosis Codocytes (target cells) Possible basophilic stippling Nucleated RBCs are usually not present Marked hypochromia and microcytosis Codocytes (target cells) Possible basophilic stippling Nucleated RBCs are usually not present Marked hypochromia and microcytosis Codocytes (target cells) schistocytes ovalocytes basophilic stippling polychromasia nucleated RBCs Possible hypochromia and microcytosis Codocytes (target cells) Basophilic stippling Reticulocyte count Normal May be slightly increased Slightly increased (<5%) Mildly increased (5 - 10%) Mildly increased Hb electrophoresis Normal pattern Decreased amount of Hb A Variable amounts of Hb A2 and Hb F Decreased amount of Hb A Variable amount of Hb A2 Hb F is usually increased Severly decreased amount of Hb A Variable amount of Hb A2 Usually an increased amount of Hb F Decreased amount of Hb A and Hb A2 Increased amount of Hb F (15 - 20%) If red blood cells are normochromic and normocytic, the RBC, Hb, and Hematocrit (HCT) test values follow in three-fold progression (i.e., RBC x 3 = Hb and Hb x 3 = HCT). This is sometimes referred to as "the rule of threes." This rule will usually not apply in cases of beta thalassemia, particularly beta thalassemia minor where the RBCs are not normochromic and are microcytic, and where there is a disproportionate number of RBCs for the amount of hemoglobin that is present.

Illustrated in the photomicrograph of a peripheral smear are two populations of erythrocytes. Approximately 50% of the erythrocytes are normal size and contain a full complement of hemoglobin. The patient had received blood transfusions. The transfused red blood cells are the normocytic, normochromic red cells. Admixed are microcytic erythrocytes and larger erythrocytes, some faintly mottled or smudged, suggestive of reticulocytes. This picture represents a hemolytic process with a reticulocyte response. A similar dimorphic red cell population appears following erythropoietin therapy. It is important to recognize when a population of cells in the peripheral smear is not in context with anticipated laboratory findings and the clinical situation.

A decreased amount of hemoglobin is referred to as hypochromasia or hypochromia. MCHC values of 30% or less reflect this condition. Hyperchromasia and hyperchromia, refer to a hypothetical situation rather than an actual occurrence. The word, hyperchromia/sia, means increase in color; however the MCHC value cannot be higher than 36, since it is impossible for a cell to contain "too much" hemoglobin.Cells located in the "too thin" portion of the smear often appear to be "hyperchromic". Megalocytes (macrocytes), which appear to have increased amounts of hemoglobin, have an MCHC value within normal limits, indicating that the cells, although larger than normal, are normochromic.