What tests should all patients with arterial thrombosis undergo?

Essential Testing for All Patients with Arterial Thrombosis

All patients with arterial thrombosis should undergo immediate diagnostic testing including blood glucose, complete blood count with platelet count, prothrombin time/INR, activated partial thromboplastin time, serum electrolytes, renal function tests, ECG, and cardiac ischemia markers. 1

Core Laboratory Tests Required for All Patients

The following tests must be performed routinely to identify systemic conditions that may cause or mimic arterial thrombosis and to guide therapeutic decisions:

Hematologic Assessment

• Complete blood count with platelet count - essential to detect thrombocytopenia or polycythemia that could influence treatment decisions 1
• Prothrombin time/INR - critical for patients on warfarin or with liver dysfunction 1
• Activated partial thromboplastin time - necessary to assess coagulation status and detect anticoagulant use 1

Metabolic and Renal Assessment

• Blood glucose - hypoglycemia can mimic stroke symptoms, and hyperglycemia is associated with worse outcomes 1
• Serum electrolytes and renal function tests - identify metabolic derangements and guide medication dosing 1

Cardiac Evaluation

• 12-lead ECG - mandatory to screen for atrial fibrillation, atrial flutter, and acute myocardial infarction 1
• Cardiac ischemia markers - acute MI can cause stroke, and stroke can precipitate myocardial ischemia 1

Additional Essential Tests

• Oxygen saturation - assess for hypoxia 1
• Fasting or nonfasting lipid profile - inform cardiovascular risk stratification 1
• HbA1c - evaluate long-term glucose control 1

Brain Imaging

CT or MRI of the brain is mandatory to distinguish ischemic stroke from hemorrhage or other structural lesions, as clinical features alone are insufficient for accurate diagnosis 1

Selective Testing Based on Clinical Context

For Unexplained or Cryptogenic Arterial Thrombosis

When arterial thrombosis occurs without clear atherosclerotic or cardioembolic cause, additional workup is warranted 1, 2:

• Echocardiography (with or without contrast) - evaluate for cardiac sources of embolism 1
• Long-term cardiac rhythm monitoring - detect paroxysmal atrial fibrillation using mobile telemetry or implantable loop recorder 1
• Noninvasive vascular imaging (CTA or MRA) - identify arterial dissection, vasculitis, or moyamoya disease 1

Hypercoagulability Testing - Limited Role in Arterial Thrombosis

Routine thrombophilia testing is NOT recommended for most patients with arterial thrombosis 1. The American College of Medical Genetics specifically states that routine testing for Factor V Leiden and other inherited thrombophilias is not indicated for arterial events (stroke, acute coronary syndromes) with rare exceptions 1.

Consider hypercoagulability testing only in these specific scenarios:

• Young patients (<50 years) with arterial thrombosis lacking traditional atherosclerotic risk factors 1, 2
• Myocardial infarction in female smokers under age 50 1
• Arterial thrombosis in unusual sites without clear etiology 2, 3

When indicated, testing should include 4, 2:

• Antiphospholipid antibodies
• Tests for systemic inflammatory conditions
• Screening for occult malignancy
• Drug screening (cocaine, amphetamines)
• HIV and syphilis serology if CNS vasculitis suspected 1

Critical Timing Considerations

Do not delay acute treatment (such as thrombolytic therapy) while awaiting laboratory results unless there is clinical suspicion of bleeding abnormality, thrombocytopenia, or known anticoagulant use 1. The diagnostic evaluation should be completed or underway within 48 hours of symptom onset 1.

Common Pitfalls to Avoid

• Do not perform routine thrombophilia testing in typical arterial thrombosis cases - this differs fundamentally from venous thromboembolism workup 1
• Do not delay imaging - clinical features cannot reliably distinguish ischemic from hemorrhagic stroke 1
• Do not skip cardiac evaluation - atrial fibrillation detection changes management significantly 1
• Ensure therapeutic anticoagulation status is confirmed before attributing recurrent events to treatment failure 4