Iron Status

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 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.

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.

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.

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.

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).

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.

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.

Mean Platelet Volume (MPV) measures the average size of platelets in the blood. Younger platelets released from the bone marrow are typically larger. High MPV can indicate increased platelet production and turnover, sometimes seen with inflammation, recovery from thrombocytopenia, or certain genetic conditions. Low MPV might suggest impaired platelet production (e.g., aplastic anemia). Interpretation often combined with platelet count and PDW.

Absolute Neutrophil Count (ANC) measures the total number of neutrophils per volume of blood (WBC count x Neutrophil %). It provides a direct measure of the body's primary defense against bacterial infections. Low ANC (neutropenia, especially <1000 or <500 cells/uL) significantly increases infection risk, often seen after chemotherapy or with certain disorders. High ANC (neutrophilia) typically indicates infection or inflammation.

Absolute Lymphocyte Count (ALC) measures the total number of lymphocytes (T cells, B cells, NK cells) per volume of blood (WBC count x Lymphocyte %). Low ALC (lymphopenia, <1000 cells/uL) can indicate viral infections (like HIV, COVID-19), immune deficiencies, malnutrition, or stress (high cortisol), and is associated with increased mortality risk. High ALC (lymphocytosis) is common in viral infections (like mono) or certain leukemias/lymphomas.

Absolute Eosinophil Count (AEC) measures the total number of eosinophils per volume of blood (WBC count x Eosinophil %). High AEC (eosinophilia, typically >500 cells/uL) is a key indicator of allergic reactions (asthma, eczema, hay fever), parasitic infections, certain skin disorders, drug reactions, or rarer eosinophilic syndromes.

Absolute Basophil Count (ABC) measures the total number of basophils per volume of blood (WBC count x Basophil %). Basophils are the least common granulocyte. Elevated ABC (basophilia) is relatively rare but can be associated with allergic reactions, chronic inflammation, hypothyroidism, or myeloproliferative disorders like CML.

Neutrophils Percentage represents the proportion of neutrophils among all white blood cells in a differential count. Neutrophils are the most abundant type of WBC and are primary responders to bacterial infections. Increased percentage (relative neutrophilia) suggests infection or inflammation, while decreased percentage (relative neutropenia) might be seen with increases in other cell types like lymphocytes.

Eosinophils Percentage indicates the proportion of eosinophils in the WBC differential. Eosinophils are involved in fighting parasitic infections and modulating allergic inflammatory responses. Increased percentage (eosinophilia) is commonly associated with allergies, asthma, parasitic infections, and certain skin or inflammatory disorders.

Basophils Percentage represents the proportion of basophils, the least common type of granulocyte. They contain histamine and heparin and are involved in allergic reactions and inflammatory responses. Increased percentage (basophilia) is uncommon but can be seen in allergic reactions, chronic inflammation, hypothyroidism, or certain blood disorders (like CML).