Take the 2-minute tour ×
Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It's 100% free, no registration required.

What purpose does the wedge product symbol serve in the formula for calculating a patient's international normalized ratio (INR) for managing warfarin doses?

The formula is:

$INR=(PT/MNPT)\wedge ISI$

INR = international normalized ratio PT = prothrombin time MNPT = mean normal prothrombin time ISI = international sensitivity index

share|improve this question
add comment

1 Answer

Apparently it is exponentiation, compare


Calculate the International Normalized Ratio using the numbers above as an example. INR=(patient PT/MNPT)^ ISI = (15.2 s/13.1 s)^1.297=1.213. Note: Normal INR should be between 0.8 and 1.3 Low values of INR (less than 0.5 ) indicate a high risk of a clot, while high values (3 to 5) are associated with risk of bleeding.

Read more: How to Calculate INR | eHow.com http://www.ehow.com/how_5108528_calculate-inr.html#ixzz2790CNQ5o


So, numerically, $$15.2 / 13.1 \approx 1.1603,$$ then $$ 1.1603^{1.297} \approx 1.213. $$

If you are not sure how to do the exponentiation, you will need to learn something of logarithms. But my calculator has a button to do it in one step.


enter image description here

share|improve this answer
add comment

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.