Table 8.

Immediate Diagnostic Studies: Evaluation of a Patient With Suspected Acute Ischemic Stroke

All patients
  Noncontrast brain CT or brain MRI
  Blood glucose
  Oxygen saturation
  Serum electrolytes/renal function tests*
  Complete blood count, including platelet count*
  Markers of cardiac ischemia*
  Prothrombin time/INR*
  Activated partial thromboplastin time*
  ECG*
Selected patients
  TT and/or ECT if it is suspected the patient is taking direct thrombin inhibitors or direct factor Xa inhibitors
  Hepatic function tests
  Toxicology screen
  Blood alcohol level
  Pregnancy test
  Arterial blood gas tests (if hypoxia is suspected)
  Chest radiography (if lung disease is suspected)
  Lumbar puncture (if subarachnoid hemorrhage is suspected and CT scan is negative for blood
  Electroencephalogram (if seizures are suspected)
  • CT indicates computed tomography; ECG, electrocardiogram; ECT, ecarin clotting time; INR, international normalized ratio; MRI, magnetic resonance imaging; and TT, thrombin time.

  • * Although it is desirable to know the results of these tests before giving intravenous recombinant tissue-type plasminogen activator, fibrinolytic therapy should not be delayed while awaiting the results unless (1) there is clinical suspicion of a bleeding abnormality or thrombocytopenia, (2) the patient has received heparin or warfarin, or (3) the patient has received other anticoagulants (direct thrombin inhibitors or direct factor Xa inhibitors).