From the Guidelines
Hematocrit is a blood test that measures the percentage of your blood volume that is made up of red blood cells, with a normal range typically between 38.3% and 48.6% for adult men and 35.5% and 44.9% for adult women, although the most recent and highest quality study suggests that hemoglobin is a more accurate measure of anemia than hematocrit 1.
Importance of Hematocrit
Hematocrit is an important test because it helps doctors evaluate your overall health and detect conditions such as anemia (low hematocrit) or polycythemia (high hematocrit) 1. The test works by spinning a blood sample in a centrifuge, which separates blood components based on density, allowing measurement of the proportion of red blood cells compared to the total blood volume.
Interpretation of Results
Low hematocrit values may indicate blood loss, nutritional deficiencies (particularly iron, vitamin B12, or folate), bone marrow problems, or chronic diseases, while high values might suggest dehydration, lung disease, heart disease, or bone marrow disorders that cause overproduction of red blood cells 1.
Clinical Recommendations
The mainstay of therapy for patients with polycythemia vera is phlebotomy to keep the hematocrit level below 45% in white men and the appropriate corresponding values for females and those of other races, with cytoreductive chemotherapy considered in patients who are at high risk for thrombosis 1.
Limitations of Hematocrit
However, hematocrit is not always a reliable measure, as it can be affected by factors such as blood sample storage conditions and hyperglycemia, which can falsely elevate the measured hematocrit level 1. Therefore, hemoglobin is generally considered a more accurate measure of anemia than hematocrit, particularly in patients with chronic kidney disease 1.
From the Research
Definition of Hematocrit
- Hematocrit (Hct) is the proportion of red blood cells in the blood 2.
- It is an important parameter in the diagnosis and evaluation of anemia, as it can indicate the presence of anemia or other blood disorders 3.
Relationship with Vascular Function and Structure
- High and low hematocrit levels are associated with the risk of cardiovascular disease 2.
- A study found that hematocrit levels between 46.0-48.9% were associated with optimal vascular function and structure in men 2.
- Low and high levels of hematocrit were associated with vascular smooth muscle dysfunction, and low hematocrit levels were associated with abnormal vascular structure 2.
Measurement and Significance
- Hematocrit is typically measured as part of a complete blood count (CBC) 3.
- The results of the hematocrit test can be used to diagnose and monitor various blood disorders, including anemia and polycythemia [(3,2)].
- Abnormal hematocrit levels can indicate underlying health issues, such as dehydration, blood loss, or bone marrow disorders [(3,2)].