What labs should be included in the initial workup for a patient with acute hemorrhagic stroke?

Initial Laboratory Workup for Acute Hemorrhagic Stroke

The initial laboratory workup for a patient with acute hemorrhagic stroke should include blood glucose, serum electrolytes/renal function tests, complete blood count with platelet count, coagulation studies (PT/INR and aPTT), cardiac markers, and oxygen saturation measurement. 1

Core Laboratory Tests (Required for All Patients)

• Blood glucose: Essential to rule out hypoglycemia which can mimic stroke symptoms and because hyperglycemia is associated with worse outcomes in hemorrhagic stroke 1
• Serum electrolytes and renal function tests: Electrolyte imbalances can produce stroke-like symptoms and assessment of renal function is important for subsequent management decisions 1
• Complete blood count with platelet count: Critical to assess for thrombocytopenia which may contribute to hemorrhage or affect management decisions 1
• Coagulation studies:
  • Prothrombin time/International Normalized Ratio (PT/INR) 1
  • Activated partial thromboplastin time (aPTT) 1
  • These are particularly important in hemorrhagic stroke to identify coagulopathies that may have contributed to the bleeding or that may affect management
• Cardiac markers: To identify concurrent cardiac conditions that may be related to the stroke 1
• Oxygen saturation: To assess for hypoxia which can worsen brain injury 1
• ECG: To identify cardiac arrhythmias (particularly atrial fibrillation) or evidence of structural heart disease 1

Additional Laboratory Tests (Based on Clinical Indications)

• Hepatic function tests: Particularly important in patients with suspected liver disease or alcohol use 1
• Toxicology screen: When drug use is suspected or the clinical presentation is atypical 1
• Blood alcohol level: When alcohol intoxication is suspected 1
• Pregnancy test: For women of childbearing age 1
• Arterial blood gas: When hypoxia is suspected or in patients with respiratory compromise 1

Clinical Considerations and Pitfalls

• Time is critical: Laboratory testing should not delay neuroimaging (CT or MRI), which is the definitive test to confirm hemorrhagic stroke 1, 2
• Coagulation abnormalities: Pay particular attention to coagulation studies in hemorrhagic stroke patients, as abnormalities may require urgent correction 3
• Medication history: Document any anticoagulant or antiplatelet medication use, as this significantly impacts management 4
• Serial monitoring: Consider repeat laboratory testing to monitor for evolving abnormalities, particularly in coagulation parameters and electrolytes 5
• Physiologic parameters: Blood pressure, serum pH, and PaO2 on admission are significant predictors of mortality in hemorrhagic stroke patients 5

Diagnostic Algorithm

1. Immediate labs (draw before or concurrent with neuroimaging):

   • Blood glucose
   • Complete blood count with platelets
   • PT/INR and aPTT
   • Electrolytes and renal function
   • Cardiac markers
   • Oxygen saturation measurement 1

2. Secondary labs (based on clinical scenario):

   • Hepatic function tests
   • Toxicology screen/blood alcohol
   • Pregnancy test
   • Arterial blood gases 1

3. Neuroimaging: Non-contrast CT or MRI of the brain is the definitive test to confirm hemorrhagic stroke 1, 2

4. Additional vascular imaging: Consider CT angiography or MR angiography to identify underlying vascular abnormalities such as aneurysms or arteriovenous malformations 1

By systematically addressing these laboratory parameters, clinicians can better assess the severity, potential causes, and appropriate management strategies for patients with acute hemorrhagic stroke.