Hemoglobinopathy Fractionation Cascade

Platelet Count measures the number of platelets (thrombocytes) per volume of blood. Platelets are small cell fragments crucial for blood clotting (hemostasis). Low platelet count (thrombocytopenia) increases bleeding risk, while high count (thrombocytosis) can increase clotting risk and may indicate inflammation, infection, iron deficiency, or underlying myeloproliferative disorders.

White Blood Cell (WBC) Count, also known as leukocyte count, measures the total number of white blood cells in the blood. These cells are key components of the immune system. Elevated levels (leukocytosis) often indicate infection, inflammation, or stress, while low levels (leukopenia) can result from bone marrow issues, certain infections, or medications, increasing susceptibility to infection.

Red Cell Distribution Width (RDW or RDW-CV) measures the variation in the size of red blood cells (anisocytosis), reported as a percentage coefficient of variation. A high RDW indicates a large variation in cell sizes, commonly seen early in iron deficiency anemia (mix of small and normal cells) and B12/folate deficiency (mix of large and normal cells), often before MCV changes. Consistently low RDW (<13%) is generally considered optimal, indicating uniform cell size.

Mean Corpuscular Volume (MCV) measures the average size (volume) of red blood cells. It is crucial for classifying anemia: low MCV (<80 fL) indicates microcytic anemia (e.g., iron deficiency, thalassemia), normal MCV (80-100 fL) indicates normocytic anemia (e.g., chronic disease, acute blood loss), and high MCV (>100 fL) indicates macrocytic anemia (e.g., B12/folate deficiency, liver disease, alcohol excess).

Mean Corpuscular Hemoglobin (MCH) measures the average amount (weight) of hemoglobin within a single red blood cell. It tends to correlate with MCV; smaller cells (low MCV) generally have less hemoglobin (low MCH), and larger cells (high MCV) have more. Low MCH (<27 pg) (hypochromia) is typical in iron deficiency anemia and thalassemia.

Red Blood Cell (RBC) Count measures the number of red blood cells per volume of blood. RBCs contain hemoglobin and are responsible for transporting oxygen from the lungs to the tissues. Low RBC count (anemia) reduces oxygen-carrying capacity, while high count (polycythemia or erythrocytosis) increases blood viscosity.

Hematocrit (Hct), also known as Packed Cell Volume (PCV), measures the percentage of blood volume occupied by red blood cells. It generally correlates with hemoglobin and RBC count and is used to assess anemia or polycythemia/erythrocytosis. Dehydration can falsely elevate hematocrit.

Hemoglobin (Hgb) is the protein within red blood cells that binds to and carries oxygen. Measuring hemoglobin concentration is a primary test for anemia (low Hgb) or polycythemia/erythrocytosis (high Hgb). Anemia leads to fatigue and reduced exercise capacity due to impaired oxygen delivery.

Mean Corpuscular Hemoglobin Concentration (MCHC) measures the average concentration of hemoglobin within red blood cells (relative to cell volume). Low MCHC (<32 g/dL) indicates hypochromia (paler cells), seen in iron deficiency and thalassemia. High MCHC (>36 g/dL) is less common but can occur in conditions like spherocytosis or due to artifact (e.g., cold agglutinins, lipemia).

Ferritin is the most sensitive test for iron stores in the body, but it can also be elevated during inflammation, which can mask iron deficiency. Use our Iron Status Interpreter for a comprehensive assessment of your iron levels.

Hemoglobin A2 is a minor component of adult hemoglobin, typically making up 1.8-3.5% of the total. An elevated level of Hemoglobin A2 is a key diagnostic marker for beta-thalassemia trait, as the body compensates for deficient beta-globin chain production by increasing alpha- and delta-chain production.

Hemoglobin F (fetal hemoglobin) is the primary oxygen-carrying protein during fetal life. Levels are normally high at birth and decrease to adult levels (typically <2%) within the first year. Elevated levels in adults can indicate certain genetic conditions like beta-thalassemia or sickle cell disease, or be a response to acquired conditions like aplastic anemia.

Hemoglobin S is an abnormal variant of hemoglobin that causes red blood cells to become rigid and sickle-shaped. Its presence is the hallmark of sickle cell trait (if heterozygous, with Hgb A also present) or sickle cell disease (if homozygous or combined with another variant). Any detectable amount is abnormal.

Hemoglobin A is the most common type of hemoglobin in healthy adults, typically comprising about 95-98% of total hemoglobin. It is composed of two alpha and two beta globin chains. Measuring its percentage is crucial for diagnosing hemoglobinopathies like thalassemias or sickle cell trait, where its proportion may be decreased.