From the Guidelines
Elevated hematocrit levels should be maintained strictly below 45% to efficiently reduce the risk of thrombotic events. This is based on the findings of a recent multicentre, randomised clinical trial (CYTO-PV) [ 1 ]. The implications of elevated hematocrit levels are significant, as they can increase blood viscosity, leading to clotting, stroke, or heart problems if left untreated.
Causes and Treatment
The causes of elevated hematocrit levels can vary, including dehydration, living at high altitude, smoking, lung disease, certain heart conditions, or polycythemia vera (a bone marrow disorder) [ 1 ]. Treatment depends on the underlying cause, but may include:
- Increasing fluid intake for dehydration
- Phlebotomy (blood removal) for polycythemia vera
- Addressing underlying conditions like sleep apnea or heart disease
- Low-dose aspirin to reduce the risk of vascular events [ 1 ]
- Cytoreductive drugs, such as hydroxyurea (HU) or IFN-α, for high-risk patients [ 1 ]
Management and Lifestyle Modifications
In addition to treatment, lifestyle modifications can help maintain normal hematocrit levels, including:
- Staying well-hydrated
- Avoiding tobacco
- Managing underlying health conditions
- Regular blood tests to monitor hematocrit levels
- Considering alternative treatments, such as IFN-α or JAK2 inhibitors, for young subjects or those previously treated with other myelosuppressive agents [ 1 ]
Importance of Medical Evaluation
If you have an elevated hematocrit, it is essential to consult with a healthcare provider to determine the underlying cause and develop an appropriate treatment plan. In severe cases with symptoms like headaches, dizziness, or blood clots, immediate medical attention is necessary. Maintaining hematocrit levels below 45% is crucial to reduce the risk of thrombotic events and improve overall health outcomes [ 1 ].
From the Research
Implications of Elevated Hematocrit Levels
Elevated hematocrit (Hct) levels can have several implications, including:
- Increased risk of thrombosis, as an elevated hematocrit can lead to increased blood viscosity 2
- Association with polycythemia vera, a condition characterized by an overproduction of red blood cells, which can increase the risk of thrombosis 3
- Increased risk of venous thromboembolism (VTE), particularly provoked VTE, in individuals with high hematocrit levels 4
- Effects on coagulation testing values, including prothrombin time (PT) and activated partial thromboplastin time (aPTT), which can be altered in patients with high hematocrit values 5
- Potential for falsely elevated prothrombin time and international normalized ratio (INR) in patients with secondary polycythemia, due to the decreased plasma volume and reduced coagulating factors available 6
Clinical Considerations
In patients with elevated hematocrit levels, it is essential to:
- Diagnose the underlying cause of the elevated hematocrit, such as polycythemia vera or secondary polycythemia, to provide optimal therapy 2
- Consider the potential for thrombotic risk and take measures to reduce this risk, such as phlebotomy or anticoagulation therapy 3
- Adjust citrate concentrations for blood coagulation specimens to ensure accurate results in patients with high hematocrit values 5, 6
- Be aware of the potential for falsely elevated PT and INR in patients with secondary polycythemia and take steps to confirm the diagnosis 6