INR Ratio
Compute the international normalized ratio as (patient PT / mean normal PT)^ISI. Use the International Sensitivity Index assigned to the specific thromboplastin reagent and instrument; the default of one is only appropriate when that is the calibrated ISI.
Description
Compute the international normalized ratio as (patient PT / mean normal PT)^ISI. Use the International Sensitivity Index assigned to the specific thromboplastin reagent and instrument; the default of one is only appropriate when that is the calibrated ISI.
INR Ratio is a focused biology tool that compute the international normalized ratio as (patient PT / mean normal PT)^ISI. Use the International Sensitivity Index assigned to the specific thromboplastin reagent and instrument; the default of one is only appropriate when that is the calibrated ISI. It calculates locally from the values you enter and exposes the result without changing the source observations.1
When to use INR Ratio
Use INR Ratio when you need to compute the international normalized ratio as (patient PT / mean normal PT)^ISI. Use the International Sensitivity Index assigned to the specific thromboplastin reagent and instrument; the default of one is only appropriate when that is the calibrated ISI. Enter Patient PT, Mean normal PT, and ISI using the definitions and units below so the result can be reproduced.
- Patient PT
- A finite measured or assumed value, expressed in s.
- Mean normal PT
- A finite measured or assumed value, expressed in s.
- ISI
- International Sensitivity Index for the reagent/instrument.
How INR Ratio calculates the result
The published tool contract uses this rule: Compute the international normalized ratio as (patient PT / mean normal PT)^ISI. Use the International Sensitivity Index assigned to the specific thromboplastin reagent and instrument; the default of one is only appropriate when that is the calibrated ISI.
- INR
- The calculated inr.
Limitations of INR Ratio
A ratio or percentage can conceal the scale of its numerator and denominator and becomes sensitive to measurement error when the denominator is small.
Alternative or Complementary measurements
Retain the original Patient PT, Mean normal PT, and ISI values and their units alongside the result. Ferritin Per Iron Ratio is useful when you instead need to compute the ratio of ferritin in nanograms per millilitre to serum iron in micrograms per decilitre. APTT Ratio provides another view by helping you compute the activated partial thromboplastin time ratio as the patient APTT divided by the control APTT.
References
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Prothrombin time — Wikipedia contributors
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- APTT Ratio
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