Test Details: Hemoglobin test is performed to check the overall health. The doctor may test hemoglobin as part of a complete blood count during a routine medical examination to monitor general health and to screen for a variety of disorders such as anemia. The doctor may suggest a hemoglobin test if one is experiencing weakness, fatigue, shortness of breath or dizziness. These signs and symptoms may point to anemia or polycythemia vera. Hematocrit (HCT) is used to measure red blood cell mass. A lower than normal hematocrit can indicate: an insufficient supply of healthy red blood cells (anemia), infection or a white blood cell disorder such as leukemia or lymphoma, vitamin or mineral deficiencies. A higher than normal hematocrit can indicate: dehydration, a disorder, such as polycythemia vera, that causes increased production of red blood cells, lung or heart disease.