Blood Tests Before IV Alteplase for Acute Ischemic Stroke
Only blood glucose measurement is mandatory before initiating IV alteplase—all other laboratory tests should be sent but must not delay treatment. 1
Mandatory Pre-Treatment Testing
- Capillary or serum blood glucose must be checked immediately and hypoglycemia (glucose <60 mg/dL or 3.3 mmol/L) must be treated with IV dextrose before alteplase administration. 1
- This is the single laboratory value that must be obtained and corrected prior to treatment in all patients. 1
Laboratory Tests That Should Be Sent (But Not Awaited)
The following tests should be ordered immediately upon arrival but treatment should proceed without waiting for results: 1, 2
- Complete blood count with platelet count 1, 2
- Serum electrolytes and creatinine 1
- INR and partial thromboplastin time (aPTT) 1, 2
- Prothrombin time (PT) 2
- Serum troponin 1
- Electrocardiography 1
When You Must Wait for Coagulation Studies
Stop and wait for laboratory results only in these specific circumstances: 2
- Known warfarin use - Must confirm INR ≤1.7 and PT <15 seconds before treatment 2
- Known heparin use - Must confirm aPTT ≤40 seconds before treatment 2
- Clinical suspicion of bleeding disorder or thrombocytopenia - Must confirm platelets ≥100,000/mm³ before treatment 2
- Uncertain anticoagulation history - Must obtain coagulation studies before treatment 2
Critical Laboratory Contraindications
Do not administer alteplase if laboratory values reveal: 2
Special Anticoagulation Considerations
- For patients on direct oral anticoagulants (DOACs) - Do not administer alteplase unless specific factor Xa or thrombin assays are normal OR the patient has not received a dose for >48 hours with normal renal function. 2
- For patients on low molecular weight heparin (LMWH) - Do not administer alteplase if treatment dose was given within the previous 24 hours. 2
Treatment Initiation Strategy
In patients without known anticoagulant use or bleeding concerns: 2
- Begin alteplase immediately after CT confirms no hemorrhage and glucose is checked 1
- Treatment can be initiated before platelet count is available but should be discontinued if platelets return <100,000/mm³ 2
- Treatment can be initiated before coagulation studies are available but should be discontinued if INR >1.7 or PT is abnormally elevated 2
Common Pitfalls to Avoid
- Never delay treatment to wait for a "complete workup" in patients without bleeding concerns or known anticoagulant use—time is brain tissue. 1
- Do not confuse this with myocardial infarction protocols where more extensive laboratory testing may be required before thrombolysis. 3
- Remember that electrocardiography and troponin are recommended to identify concomitant acute coronary syndrome but should not delay stroke treatment. 1