Hematologic 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.

In addition to hereditary hemochromatosis (HH), there are other conditions of iron overload that must be considered in a differential diagnosis. Disorders such as sickle cell disease, thalassemia, sideroblastic anemia, congenital dyserythropoietic anemia, and liver disease may also cause iron overload. Transfusion-dependant patients and persons who abuse iron-containing vitamin supplements are also at risk. These conditions are usually described as secondary iron overload, in contrast to the primary iron overload of HH.Patient history, clinical signs and symptoms, biochemical and hematologic laboratory analyses, and possibly results of a liver biopsy may be needed to establish a diagnosis of a condition causing secondary iron overload. DNA tests for common HFE mutations are very likely the most important diagnostic tool for identifying HH as the cause of iron overload. In some patients, both secondary causes and HH may be contributing to iron overload. Differentiating the secondary causes of iron overload from HH is heavily dependent on the results of laboratory assays, but a complete discussion is beyond the scope of this course.

Evaluation of the bone marrow provides both diagnostic and prognostic information for a number of hematologic disorders. Indications for performing a bone marrow include an increase or decrease of any blood cellular element.