Versiti - Diagnostic Laboratories

Platelet Aggregation Form

Platelet Aggregation Requisition and Appointment Form

Phone: 800-245-3117 x 6250 | Fax: 414-937-6184 |

Instructions: Please complete this form and attach a summary of all medications the patient is taking to this appointment form; medication summary is not needed for Ristocetin Induced Platelet Aggregation. Patient should be off all non-essential medications for at least 10 days. Medications that contain aspirin or ibuprofen (Motrin or Advil), Naproxen (Aleve), cold/sinus/cough medications will affect this test and should not be taken within 10 days of the scheduled appointment. Acetaminophen (Tylenol) is acceptable. If you would like to discuss your patient’s medications with one of our Hemostasis Medical Directors, please contact our Client Services team for a referral by calling 800-245-3117 x 6250 or email us at

Testing available for local Wisconsin-based clients only.

Versiti does NOT bill patients or insurance. Test orders must be placed through a medical facility that has an account with Versiti. Client # required.

Ordering Institution Information

If testing is intended for a Medicare enrollee or Wisconsin Medicaid recipient, please download and complete the Medicare Beneficiary Form and attach below.

Patient Information

Sample Requirements

  • Platelet Aggregation (1175) and Ristocetin Induced Platelet Aggregation (1068): Twelve (12) 4.5 mL samples in 3.2% buffered sodium citrate, glass or plastic evacuated tubes
  • Single Platelet Agonist Aggregation (1250, 1255, 1260, or 1270): Six (6) 4.5 mL samples in 3.2% buffered sodium citrate, glass or plastic evacuated tubes
  • Maintain whole blood sample at room temperature (do not process the sample)
  • Do not send samples through a pneumatic tube system
  • Notify Versiti Hemostasis Lab at 414-937-6129 when sample is drawn
  • A completed Versiti Platelet Aggregation Requisition should be sent with the sample
  • Transport samples and requisition to the Versiti Hemostasis lab within two hours of the draw time. Samples should be delivered to the 17th Street entrance.

Note: It is the responsibility of the drawing institution to transport the sample.

Patient Questions

10 days post-platelet transfusion is recommended, but not required.

Please enter platelet count without any commas, spaces or other special characters.

NOTE: If platelet count is < 100,000, a platelet aggregation profile cannot be performed. A physician consult can be set up with the Hemostasis Lab Medical Director to consult with the patient’s physician. 

If looking for Bernard-Soulier Syndrome, Type 2B VWD, or Platelet-type VWD, we can perform the ristocetin aggregation (RIPA) as low as 50,000 platelet count. If the platelet count is < 50,000, the ordering physician must consult with the Hemostasis Lab Medical Director.

Please attach a summary of all medications the patient is taking and indicate which medications are being withheld prior to platelet aggregation testing.

If you would like to copy and paste or type any specific patient medication list notes, please use the field below.

* Fields are required.