From the Guidelines
Brain bleeds are definitively diagnosed through imaging studies, primarily CT scans or MRI, which can directly visualize the hemorrhage, rather than laboratory tests like complete blood counts (CBC) and coagulation studies (PT, PTT) 1. These blood tests help assess clotting function and identify factors that might contribute to bleeding risk, such as thrombocytopenia (low platelet count) or coagulopathy. However, they play an important supportive role in diagnosis and management, and are valuable for determining potential causes of the bleed, guiding treatment decisions (especially regarding anticoagulation), and monitoring the patient's condition. For example, elevated INR might indicate excessive anticoagulation as a contributing factor to the hemorrhage, as noted in the 2022 guideline for the management of patients with spontaneous intracerebral hemorrhage 1. Some key laboratory tests that can provide supportive information include:
- Complete blood count to assess for thrombocytopenia or other abnormalities
- Coagulation studies, including prothrombin time (PT) and partial thromboplastin time (PTT), to evaluate clotting function
- INR to assess the effectiveness of anticoagulation therapy and potential risk of bleeding While these tests are essential components of the workup for suspected brain bleeds, they serve as complementary tools rather than confirmatory tests, with neuroimaging remaining the gold standard for diagnosis, as recommended in the 2021 guideline for the prevention of stroke in patients with stroke and transient ischemic attack 1.
From the Research
Lab Tests for Brain Bleed
To confirm a brain bleed, several lab tests can be utilized, including:
- Complete blood counts (CBC) to evaluate overall blood cell counts and detect any abnormalities
- Coagulation studies, such as prothrombin time (PT) and partial thromboplastin time (PTT), to assess the blood's clotting ability
- Thrombelastography (TEG) to evaluate the viscoelastic properties of blood clotting
- Factor XIII activity tests to determine the risk of postoperative hemorrhage after intracranial surgery
Coagulation Studies
Coagulation studies, including PT and PTT, can help identify patients with coagulopathy, which is associated with worse outcomes in patients with intracranial hemorrhage or traumatic brain injury 2. However, routine screening of all preoperative neurosurgical patients may be unnecessary, as abnormal results are often predictable based on patient history 3.
Viscoelastic Assays
Viscoelastic assays, such as TEG, can provide additional information on the coagulation status of patients with intracranial hemorrhage or traumatic brain injury 2. TEG can help identify patients with hypocoagulability, which is associated with a higher risk of worse prognosis.
Factor XIII Activity
Factor XIII activity tests can help determine the risk of postoperative hemorrhage after intracranial surgery 4. Patients with decreased factor XIII activity have an increased risk of postoperative hematoma, and factor XIII testing and specific replacement may reduce this risk.
Imaging Studies
Imaging studies, such as computed tomography (CT) scans, are also crucial in diagnosing brain bleeds 5. CT scans can help identify the presence and location of intracranial hemorrhage, as well as any associated mass effect or midline shift. Computer-aided assessment of CT scans can also improve the accuracy of diagnosis and help identify patients with acute intracranial hemorrhage 5.