Massachusetts General Hospital

Coagulation (Core Lab)



Medical Director: Sacha Uljon, M.D.,Ph.D.., Phone: 617-726-0602
Technical Director: Jennifer Hiers, Phone: 617-726-3609
Supervisor: Ryan Mize, Phone: 617-724-1863
Technical Specialist: John Barranco, MLS, Phone: 617-724-5539


The Coagulation Laboratory is in operation 7 days a week, 8 am to 4:00 pm, except for holidays, when it is closed. When the laboratory is closed, specimens should be delivered to the Core Laboratory on Gray 5. Many of the tests performed are of a batch nature.


  1. Argatroban, bivalirudin, dabigatran, apixaban, or rivaroxaban anticoagulation interfere with some coagulation assays.
  2. When multiple tests are ordered simultaneously, a maximum of 5 blue top tubes is typically sufficient for all tests. Please contact the lab at 617-724-2969 for minimum volume requirements PRIOR to drawing more than 5 tubes.
  3. Clotted, underfilled or overfilled specimens give unreliable results and will be refused.
  4. Platelet aggregation studies are performed Monday, Wednesday, Friday and must be scheduled in advance (call 617-724-2969). Samples should not be drawn earlier than 8am and must be received by 12pm
    – Platelet aggregation samples must be received within 2 hours of collection
    – 8 blue top tubes at room temperature are needed for platelet aggregation.

Additional general test information and references