How does Sickle Cell Trait (SCT) cause blood to thicken, leading to potential hypercoagulability?

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Last updated: February 18, 2025View editorial policy

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From the Guidelines

Sickle cell trait does not typically cause blood to thicken, but it can increase the risk of blood clotting due to the abnormal hemoglobin in red blood cells, which can become more sticky and adhere to blood vessel walls, potentially leading to blood clot formation [ 1 ].

Key Factors

  • The abnormal hemoglobin in sickle cell trait can cause red blood cells to become more sticky, increasing the risk of clotting [ 1 ].
  • Certain conditions, such as hyperthermia, dehydration, acidosis, and hypoxemia, can promote HbS polymerization and erythrocyte sickling, leading to vascular occlusion and endothelial damage [ 1 ].
  • Individuals with sickle cell trait may be at increased risk of venous thromboembolism (VTE), particularly in certain situations, such as high-altitude areas or intense exercise [ 1 ].

Recommendations

  • It is essential for individuals with sickle cell trait to discuss their individual risk factors with their healthcare provider and follow recommendations for regular check-ups and monitoring [ 1 ].
  • Staying hydrated, avoiding high-altitude areas, and managing underlying medical conditions can help minimize the risk of complications [ 1 ].
  • Anticoagulation may be necessary for individuals with sickle cell trait who experience VTE, but the optimum duration of anticoagulation is unclear [ 1 ].

From the Research

Sickle Cell Trait and Blood Coagulation

  • Sickle Cell Trait (SCT) is a condition where an individual has one normal hemoglobin gene and one sickle hemoglobin gene, which can lead to changes in blood coagulation 2, 3.
  • Studies have shown that individuals with SCT have increased coagulation activity, which can lead to a hypercoagulable state 2, 3.
  • This hypercoagulable state can increase the risk of venous thromboembolism and other thrombotic events 2.

Mechanisms of Hypercoagulability in SCT

  • The exact mechanisms of hypercoagulability in SCT are not fully understood, but it is thought to involve changes in red blood cell morphology and function, as well as alterations in coagulation factor activity 2, 3.
  • Red blood cell-derived microparticles have been shown to be elevated in individuals with SCT, which can contribute to a prothrombotic state 2.
  • Increased levels of d-dimers, thrombin-antithrombin complexes, and prothrombin fragment 1.2 have also been observed in individuals with SCT, indicating increased coagulation activity 2, 3.

Clinical Implications

  • The increased coagulation activity associated with SCT can have significant clinical implications, including an increased risk of thrombotic events and other vascular complications 4, 5.
  • Individuals with SCT should be aware of their increased risk of thrombotic events and take steps to reduce their risk, such as staying hydrated and avoiding extreme physical exertion 5.
  • Further research is needed to fully understand the mechanisms of hypercoagulability in SCT and to develop effective strategies for preventing and managing thrombotic complications 6, 2, 3.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Procoagulant activity in patients with sickle cell trait.

Blood coagulation & fibrinolysis : an international journal in haemostasis and thrombosis, 2012

Research

Coagulation changes in individuals with sickle cell trait.

American journal of hematology, 2002

Research

Sickle Cell Trait: A Benign State?

Acta haematologica, 2016

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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