INR · high result
What does a high INR mean?
Short answer
An INR above range means blood takes longer to clot. In someone on warfarin it is the intended effect (usual target 2–3) and a value above ~4.5 raises bleeding risk. In someone not on warfarin it points to vitamin K deficiency, liver disease, antibiotics disrupting gut bacteria, inherited factor deficiencies, or sample problems — and is a finding to follow up promptly.
Medically reviewed by Youmna DiStefano, MD · Last reviewed September 2026
When does this result need same-day care?
- INR above ~5, or any elevation with bleeding that won't stop, black stools or a severe headache — same-day care
What is the normal range for INR?
- age 18+: 0.800 – 1.10 ratio
Higher than 1.1 in someone not on warfarin can indicate clotting issues. Therapeutic warfarin range is typically 2.0–3.0.
Full reference table, citations and testing options: INR biomarker page.
What are the common causes of high INR?
- Warfarin (expected; too high means over-anticoagulated)
- Liver disease — reduced clotting-factor production
- Vitamin K deficiency: poor intake, malabsorption, prolonged antibiotics, newborns
- Inherited factor VII or other factor deficiencies
- Disseminated intravascular coagulation (acute illness)
- Under-filled or heparin-contaminated tube (false high)
What symptoms go with high INR?
- Easy bruising, nosebleeds, gum bleeding, heavy periods
- Often none until quite high
What do clinicians usually check next?
- Repeat with correct collection; aPTT and platelet count
- Liver panel and albumin
- Vitamin K status/trial as directed; hematology if inherited deficiency suspected
- On warfarin: contact the prescriber the same day for values above 4.5
Follow-up tests available at TestWell: Vitamin K ($36.99).
How do you recheck INR?
Prices are cash-pay; every order adds one $6 lab processing fee. Physician authorization is included; no insurance or referral needed.
| Test or panel | Type | Price | Fasting | Results |
|---|---|---|---|---|
| Blood Clotting Panel | Panel · 4 tests | $149.99 | No | 3–7 business days |
| Prothrombin Time with INR | Test · 2 biomarkers | $23.99 | No | 1–3 business days |
Common questions
I'm not on blood thinners — why is my INR 1.3?
Mild elevations are common with liver conditions, low vitamin K intake or a recent antibiotic course. A repeat plus liver tests usually explains it; persistent elevation needs a hematology look.
Sources
Educational content, not a diagnosis. Lab results are one input; a clinician interprets them with your history and exam.