What blood work is recommended for a patient who has experienced a Transient Ischemic Attack (TIA)?

Blood Work for TIA

All patients with suspected TIA should have initial bloodwork including complete blood count, electrolytes, coagulation studies (aPTT, INR), renal function (creatinine, eGFR), random glucose, and troponin, followed by lipid profile and HbA1c or glucose tolerance testing. 1

Initial Laboratory Investigations (Perform Immediately)

The following tests should be obtained as part of the initial emergency evaluation:

Hematology and Coagulation

• Complete blood count (CBC) with platelet count to assess for polycythemia, thrombocytosis, anemia, or thrombocytopenia 1, 2
• Prothrombin time (PT) and International Normalized Ratio (INR) to evaluate coagulation status, particularly important if anticoagulation is being considered 1, 2
• Activated partial thromboplastin time (aPTT) to complete coagulation assessment 1, 2

Metabolic Panel

• Serum electrolytes to identify metabolic disturbances that could contribute to neurological symptoms 1, 2
• Renal function including creatinine and estimated glomerular filtration rate (eGFR) to guide medication dosing and assess vascular risk 1
• Random glucose to identify acute hyperglycemia or hypoglycemia, which can mimic TIA symptoms 1, 2

Cardiac Markers

• Troponin to evaluate for concurrent acute coronary syndrome, as cardiovascular disease often coexists with cerebrovascular disease 1

Subsequent Laboratory Tests (Within 24-48 Hours)

These tests may be performed during the initial encounter or as an outpatient, depending on urgency and resource availability:

Lipid Assessment

• Lipid profile (fasting or non-fasting) including total cholesterol, LDL, HDL, and triglycerides to guide secondary prevention strategies 1

Diabetes Screening

• Glycated hemoglobin (HbA1c) or 75g oral glucose tolerance test to screen for diabetes mellitus, a major modifiable stroke risk factor 1

Critical Timing Considerations

The diagnostic evaluation should be started or ideally completed within 48 hours of TIA onset, as the early stroke risk is as high as 10% within the first week for high-risk patients. 1, 3

For patients presenting within 48 hours with high-risk features (unilateral motor weakness, facial weakness, or language/speech disturbance), all bloodwork should be completed within 24 hours as part of urgent hospitalization. 3

Common Pitfalls to Avoid

• Do not delay bloodwork while waiting for imaging studies—these should be obtained simultaneously upon arrival 1
• Do not omit glucose testing, as hypoglycemia is a common TIA mimic that requires immediate identification and treatment 2
• Do not forget troponin, as concurrent cardiac ischemia may be present and requires different management 1
• Do not rely solely on initial glucose—obtain HbA1c or glucose tolerance testing to identify undiagnosed diabetes, which affects long-term stroke prevention strategies 1

Integration with Other Diagnostic Studies

Blood work should be obtained concurrently with:

• 12-lead ECG to screen for atrial fibrillation 1
• Brain imaging (CT or MRI) to exclude hemorrhage and identify infarction 1
• Vascular imaging (CTA, MRA, or carotid ultrasound) to identify stenosis requiring urgent intervention 1