COVID 19 Update
PT/INR Home Testing

What does PT/INR stand for?

Prothrombin Time / International Normalized Ratio

The INR is calculated using the following formula and Is a ratio of Prothrombin Times that doctors or pharmacists use to adjust your Coumadin® dosage.


Prothrombin Time or Protime-Measures the amount of time, in seconds, that it takes for your blood to clot.

PT Patient = Patient’s measured PT (seconds)
PT Normal = Laboratory’s geometric mean value PT for normal patients not on Coumadin (seconds)
ISI = International Sensitivity Index (1.0)
PT= Prothrombin Time (number of seconds it takes blood to clot)

Name  *
Email  *
Phone  *
Enquiry Type *
Message *
  Please enter in the number below:
Advanced Cardio Services © 2010-2023 All rights reserved.
10800 N Congress Ave, Suite C | Kansas City, MO 64153
Phone: 800-769-8177 | Fax: 844-700-3484