Which laboratory value is best for assessing anemia or bleeding?

The hemoglobin level is the most relevant laboratory value for assessing anemia or bleeding. Hemoglobin is a protein found in red blood cells responsible for transporting oxygen throughout the body. When anemia is present, either due to a reduction in red blood cell production, increased destruction of red blood cells, or loss of blood (bleeding), the hemoglobin concentration in the blood decreases.

Evaluating hemoglobin levels allows healthcare providers to determine the severity of anemia. A low hemoglobin reading indicates either a loss of blood, potentially leading to a need for further investigation to identify the source of bleeding or an underlying condition leading to decreased red blood cell production.

While hematocrit levels can also indicate anemia and are related to the volume of red blood cells in the blood, hemoglobin is often considered a more direct measure. White blood cell counts assess immune function and can indicate infection or inflammation, while platelet counts are more relevant in assessing blood clotting therapies and bleeding disorders, not general anemia or bleeding. Thus, hemoglobin is the primary indicator for these conditions.