Red blood cells (RBCs) transport oxygen from the lungs to tissues throughout the body. Laboratory tests commonly measure hemoglobin concentration (Hgb), hematocrit (Hct), and the number of RBCs per microliter of blood. These results are useful individually, but they also combine to form the RBC indices: mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC). The indices provide deeper insight into anemia, nutritional deficiencies, and other blood disorders. For example, iron deficiency often produces microcytic (small-sized) RBCs, reflected in a low MCV. Vitamin B12 deficiency, meanwhile, leads to macrocytosis—high MCV. Clinicians rely on these indices to differentiate between various causes of anemia.
The first index, MCV, indicates the average volume of a single red blood cell. It is calculated with . When hematocrit is given as a percentage and RBC count in millions per microliter, the result is in femtoliters (fL). Typical adult values range from 80 fL to 100 fL. Values below 80 fL suggest microcytosis, while values above 100 fL are consistent with macrocytosis.
MCH expresses the average mass of hemoglobin in a single RBC. It is determined by and is reported in picograms. Normal values typically fall between 27 pg and 33 pg. MCH trends often mirror MCV, because larger cells usually contain more hemoglobin. However, some conditions such as thalassemia or iron deficiency cause cells to contain less hemoglobin than expected for their size, lowering both MCH and MCHC.
MCHC measures the concentration of hemoglobin within a given volume of packed RBCs. The formula is with results in grams per deciliter. Normal ranges are usually 32–36 g/dL. Conditions that cause hemoglobin synthesis problems result in hypochromia—MCHC below 32 g/dL. Elevated MCHC, though uncommon, may signal hereditary spherocytosis or cold agglutinin disease.
Suppose you have a patient with a hemoglobin level of 11 g/dL, a hematocrit of 33%, and an RBC count of 4.2 million/µL. Plugging these into the formulas yields an MCV of roughly 78 fL, MCH of about 26 pg, and MCHC around 33 g/dL. The slightly low MCV and MCH suggest microcytic anemia, prompting further testing for iron deficiency. By contrast, a patient with Hgb 10 g/dL, Hct 31%, and RBC count 3.0 million/µL would have an MCV of 103 fL—indicating macrocytosis—so vitamin B12 or folate levels might be checked next.
While RBC indices offer invaluable clues, they are not definitive diagnoses on their own. Dehydration can alter hematocrit, while chronic illness may impact hemoglobin synthesis. Labs also vary slightly in reference ranges. Therefore, RBC indices should be interpreted alongside a patient’s symptoms, medical history, and additional testing such as reticulocyte counts or iron studies. Automated analyzers compute these indices rapidly from complete blood count data, but manual verification may be warranted in cases of abnormal cells or instrument error.
Balanced nutrition rich in iron, vitamin B12, and folate supports healthy RBC production. Individuals on plant-based diets may need supplements or fortified foods to maintain adequate B12 levels. Chronic conditions such as kidney disease can reduce erythropoietin production, leading to anemia even when nutrient intake is sufficient. If your RBC indices fall outside the normal range, consult a healthcare professional to identify underlying causes. Regular screenings can detect subtle changes before symptoms develop.
By understanding the relationships between hemoglobin, hematocrit, and RBC count, you can calculate indices that illuminate the root of many blood disorders. This calculator simplifies the math so you can focus on interpreting the results. Use it to monitor your own lab reports or to help others grasp the meaning behind the numbers. Tracking RBC indices over time reveals trends in overall health and can guide dietary or medical interventions aimed at restoring optimal blood function.
Estimate the minutes of sun exposure needed for vitamin D based on skin type, UV index, and how much skin you expose.
Answer 20 questions to compute your PCL-5 score and gauge potential PTSD severity.
Calculate the CVSS v3 base score for security vulnerabilities by selecting metrics like attack vector, complexity, and impact.