An INR of 3.1 not on warfarin
| Where it fallsthe target ranges used in warfarin management | Markedly prolonged |
|---|---|
| INRfor someone not taking warfarin | 3.1 |
| Usual reference range | 0.8 – 1.1 |
| Below the reference range | under 0.8 |
| Normal | 0.8 – 1 |
| Slightly prolonged | 1.1 – 1.4 |
| Clearly prolonged | 1.5 – 2.9 |
| Markedly prolongedthis reading | 3 and above |
Notes
- A inr of 3.1 is outside the range a web page should be the end of. Repeat the measurement, and contact a doctor rather than reading further. If it comes with chest pain, breathlessness, confusion, weakness or a change in vision, treat it as an emergency.
- Reference ranges differ between laboratories. The bands above follow the target ranges used in warfarin management. Your own report prints the range its analyser was calibrated against, and that printed range is the one to compare against — a difference of a few units between labs is normal and does not mean either is wrong.
- The INR only has a target if you are taking warfarin. Off warfarin it is a clotting measurement with a narrow normal range near 1.0, and a raised value points at liver disease, vitamin K deficiency or a clotting disorder. The 2.0–3.0 figure people quote is a treatment target, not a normal range, and applying it to someone not on warfarin inverts the meaning of the result.
- The direct oral anticoagulants do not use it. Apixaban, rivaroxaban, edoxaban and dabigatran are not monitored by INR, and an INR taken while on one of them can be mildly raised without meaning anything about the dose.
What inr of 3.1 means
A reading of **3.1 **for someone not taking warfarin falls in Markedly prolonged by the target ranges used in warfarin management.
The usual reference range is **0.8 – 1.1 **.
Reading it next to the rest of the picture
A single figure is a snapshot. What somebody experienced does with it is set by what sits around it — the other figures on the same report, the history behind them, and what the previous result was. Two people can hand over the same number and leave with different advice, and neither has been given the wrong answer.
That is also why the bands on this page are drawn from a named source rather than a rounded rule of thumb. A threshold is a decision point somebody argued for in print, not a law of nature, and knowing which document a line comes from is what lets you tell a meaningful result from a borderline one.
Nearby sizes
Read more
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- eGFR Normal Range: Above 90, and the Stages Below IteGFR is an estimate built from creatinine, age and sex — and the estimate is better than the raw creatinine it comes from, for a reason worth understanding.
- TSH Normal Range: 0.4–4.0 mIU/L, and the Number Moves BackwardsTSH runs opposite to the gland it measures. High TSH means the thyroid is underactive, and that inversion catches almost everyone reading their own result.
- Cholesterol Numbers: What Total, LDL, HDL and Triglycerides MeanA lipid panel reports four numbers and the one printed largest — total cholesterol — is the least useful of them.