Laboratory Tests for Suspected Stroke

Initial Laboratory Workup

The American Heart Association recommends that all patients with suspected stroke should immediately receive a core panel of laboratory tests including complete blood count with platelets, electrolytes, renal function, coagulation studies, random glucose or HbA1c, and troponin, along with a 12-lead ECG 1, 2, 3, 4
Complete blood count is essential to detect thrombocytopenia, anemia, or polycythemia that could influence treatment decisions 1, 2, 3, 4
Electrolytes are necessary to identify metabolic derangements that can affect management 1, 2, 3, 4
Renal function tests are critical for medication dosing and identifying renal dysfunction 1, 2, 3, 4
Coagulation studies are particularly important to identify coagulopathies and assess anticoagulant use, especially before considering thrombolytic therapy 1, 2, 3, 4
Random glucose or HbA1c testing is necessary as hypoglycemia can mimic stroke symptoms and must be ruled out immediately; hyperglycemia is associated with worse outcomes 1, 2, 3, 4
Troponin testing identifies concurrent cardiac conditions, as acute MI can cause stroke and stroke can precipitate myocardial ischemia 1, 2, 3, 4
A 12-lead ECG is mandatory to assess cardiac rhythm and identify atrial fibrillation, atrial flutter, or evidence of structural heart disease 1, 2, 3, 4

Lipid profile testing is recommended for cardiovascular risk assessment 1, 2, 3, 4
Diabetes screening is necessary using fasting plasma glucose, 2-hour plasma glucose, HbA1c, or 75g oral glucose tolerance test if not already obtained 1, 2, 3, 4

For Embolic Stroke of Undetermined Source (ESUS), prolonged ECG monitoring for at least 2 weeks is recommended to improve detection of paroxysmal atrial fibrillation in selected patients 1, 2, 3, 4
Echocardiography should be considered when stroke mechanism has not been identified 1, 2, 3, 4

Blood glucose testing should be performed immediately as hypoglycemia can mimic stroke and must be excluded before proceeding with other interventions 1, 2, 3, 4
The diagnostic evaluation should be completed or underway within 48 hours of symptom onset, but acute treatment should not be delayed while awaiting laboratory results unless there is clinical suspicion of bleeding abnormality, thrombocytopenia, or known anticoagulant use 6