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Therapeutics & Diagnostics 21-059

The Platelet Variability Index (PVI)

Tech ID



Donald Arnold
Na Li
Nancy Heddle
Ishac Nazy
John Kelton


CIPO Registration Number: 1208545 (December 11, 2023)

Stage of Research

Development Stage


Caryn Anthony
Licensing Associate


Immune thrombocytopenia (ITP) is a blood disorder that causes low blood platelets and bleeding. This happens when the immune system destroys the blood clotting platelets.

There is no known cause of ITP but it is due to an immune system error which could happen spontaneously or could be triggered by viral infections, pregnancy or immune disorders, such as lupus or rheumatoid arthritis. In most cases, however, there is no specific cause.

There is no reliable biomarker that can distinguish ITP from other causes of low blood platelets. As a result, patients in the clinic are often misdiagnosed. However, fluctuations in the platelet count level over time is a feature that is unique to ITP.

McMaster Researchers have developed a tool to measure platelet fluctuations over time, called the platelet variability index (PVI). The PVI tool can be used to improve diagnostic accuracy in patients with thrombocytopenia.


  • The PVI tool can help medical specialists arrive at an accurate diagnosis for patients with thrombocytopenia in the clinic.
  • The PVI tool can help ensure that participants in ITP clinical trials meet eligibility requirements.


  • The PVI tool can distinguish ITP from other thrombocytopenic disorders.
  • The PVI tool can avoid misdiagnosis of patients with low blood platelets.

Image obtained from:

Hamilton Health Sciences, St. Joseph's Healthcare Hamilton and McMaster University logos.