PT / INR Calculator | ShankarShahi.com.np

Patient PT (seconds) PT Control / Mean Normal PT (seconds) ISI

Enter Patient PT. Default PT Control = 13 sec and ISI = 1.1. Both can be edited before calculation.

Formula

INR = (Patient PT ÷ PT Control / Mean Normal PT)^ISI

Default values are provided for convenience only. Change PT Control and ISI according to your laboratory reagent/instrument settings when required.

Calculation aid only. Use the laboratory-validated mean normal PT/control value and ISI for reporting.