Below the range
Common causes of a low International Normalized Ratio (INR)
- Subtherapeutic anticoagulation
- Vitamin K-rich diet while on warfarin
Looking for the other direction? See what causes a high International Normalized Ratio (INR).
All tests · Coagulation Studies · International Normalized Ratio (INR)
Below the range
What causes a low International Normalized Ratio (INR)?
Normal range 0.8-1.1 (off anticoagulation) ratio (0.8-1.1 ratio SI). Specimen: Plasma (sodium citrate). See the full International Normalized Ratio (INR) reference page for critical values and nursing considerations.
What is the normal range for International Normalized Ratio (INR)?
The standard teaching reference range for International Normalized Ratio (INR) is 0.8-1.1 (off anticoagulation) ratio in conventional units, or 0.8-1.1 ratio in SI units. This value is measured in plasma (sodium citrate).
| Specimen | Plasma (sodium citrate) |
|---|---|
| Conventional range | 0.8-1.1 (off anticoagulation) ratio |
| SI range | 0.8-1.1 ratio |
| Critical value | > 5.0 (high spontaneous bleeding risk) |
| Panel | Coagulation Studies |
Full details, including nursing considerations, on the International Normalized Ratio (INR) normal range page. Reference ranges vary by laboratory, method, age, sex, and population - always use the range printed on the actual result.
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