From the Guidelines
For a patient with stroke-like symptoms, essential laboratory tests include a complete blood count, comprehensive metabolic panel, coagulation studies (PT/INR, PTT), blood glucose, and cardiac biomarkers (troponin) as recommended by the American Heart Association/American Stroke Association 1. The initial evaluation of a patient with suspected acute stroke should include a rapid assessment of airway, breathing, and circulation, as well as a neurological examination to determine focal neurological deficits and assess stroke severity 1. The following laboratory tests are recommended:
- Electrolytes
- Glucose
- Hematology (CBC)
- Coagulation (INR, aPTT)
- Creatinine
- eGFR
- Troponin An electrocardiogram should also be completed as part of the initial evaluation 1. A D-dimer is not routinely indicated for suspected stroke but may be useful if venous thromboembolism is suspected as a differential diagnosis. Cardiac biomarkers, such as troponin, are important in the evaluation of patients with stroke-like symptoms, as they can help diagnose myocardial injury and identify patients at risk for cardiac complications 1. The most critical imaging study is an immediate non-contrast head CT to differentiate between ischemic and hemorrhagic stroke, as this distinction determines treatment approach. Time is crucial in stroke management, as thrombolytic therapy must be administered within a specific window for ischemic strokes, while it's contraindicated in hemorrhagic strokes. Some key points to consider in the management of patients with stroke-like symptoms include:
- The importance of rapid evaluation and treatment
- The need for careful assessment of cardiac risk factors and cardiac biomarkers
- The role of imaging studies, such as non-contrast head CT, in determining the diagnosis and treatment approach
- The importance of considering alternative diagnoses, such as venous thromboembolism, and ordering appropriate laboratory tests, such as D-dimer, as needed.
From the Research
Laboratory Tests for Stroke-Like Symptoms
When a patient presents with stroke-like symptoms, several laboratory tests can be ordered to aid in diagnosis and management. These tests include:
- Complete Blood Count (CBC) to evaluate for underlying hematological disorders, such as thrombophilia or myeloproliferative diseases 2, 3, 4
- Blood glucose levels to rule out hypoglycemia, a common stroke mimic 5
- Electrolyte panel to assess for any electrolyte imbalances that may be contributing to the patient's symptoms
- Renal function tests to evaluate for any underlying kidney disease that may be contributing to the patient's symptoms
Cardiac Biomarkers
Cardiac biomarkers, such as troponin, can be useful in evaluating patients with stroke-like symptoms, particularly if there is a concern for cardiac embolism as the source of the stroke. However, the use of cardiac biomarkers in this setting is not universally recommended and should be individualized based on the patient's clinical presentation and risk factors.
D-Dimer
A D-dimer test is not typically recommended as a routine test in the evaluation of stroke-like symptoms, unless there is a high suspicion for venous thromboembolism or other conditions that may cause elevated D-dimer levels 5. The D-dimer test has limited sensitivity and specificity for diagnosing stroke, and its use in this setting is not well established.
Other Tests
Other laboratory tests that may be ordered in the evaluation of stroke-like symptoms include:
- Coagulation studies, such as prothrombin time and partial thromboplastin time, to evaluate for any underlying coagulopathy
- Liver function tests to assess for any underlying liver disease that may be contributing to the patient's symptoms
- Thyroid function tests to evaluate for any underlying thyroid disease that may be contributing to the patient's symptoms
- Toxicology screens to rule out any substance-related causes of the patient's symptoms 5