INR: normal range and what it means
A standardized clotting ratio (key if on blood thinners).
Normal range
Adult reference range.
- Low< 0.8 ratio
- Normal0.8 – 1.2 ratio
- High≥ 1.2 ratio
What it measures
Prothrombin time expressed on a standard scale, so a result means the same thing in any lab. It exists mainly so warfarin can be dosed consistently.
What moves it
A standardised version of prothrombin time. Driven by warfarin dose, vitamin K in the diet, and liver function.
How to bring it into range
If you take warfarin, keep vitamin K intake steady rather than avoiding it. Swings in leafy greens are what move this number.
How fast it responds
Two to five days after a dose change.
Also reported as: international normalized ratio
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Common questions
- What is a normal INR level?
- Normal: 0.8 – 1.2 ratio. Adult reference range.
- What does a high INR mean?
- A value above the reference band means INR is outside the range typical for a healthy adult. A single reading is rarely conclusive on its own — what matters is the trend across draws and the other markers around it, which is why HealthOS reads the whole panel together rather than one number at a time.
- How do I improve my INR?
- If you take warfarin, keep vitamin K intake steady rather than avoiding it. Swings in leafy greens are what move this number.
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Reference ranges are general-population guidance compiled from common clinical laboratories, not a diagnosis. Lab-to-lab ranges differ. Always read your results with your doctor.