Order Prothrombin Time (PT/INR) - Blood Clotting Test from JustLabs for $8. Price includes lab processing at Quest Diagnostics. A one-time $18 collection fee applies per order. No insurance required.
Measures how quickly your blood clots. Essential for anyone on blood thinners like warfarin, or investigating unexplained bleeding or bruising.
The Prothrombin Time (PT) test measures how long it takes for your blood to clot. The result is also expressed as an INR (International Normalized Ratio), which standardizes results across different laboratories.
This test evaluates the extrinsic and common pathways of blood coagulation, specifically measuring the function of clotting factors I (fibrinogen), II (prothrombin), V, VII, and X.
For people taking warfarin (Coumadin), regular PT/INR monitoring is critical to ensure the medication is working properly without increasing bleeding risk.
Price
$8
Results
1 business days
Lab Network
Quest
Fasting
Not Required
What's Measured
What This Test Measures
This test measures two related values:
- PT (Prothrombin Time): The time in seconds for blood to clot (normal: 11-13.5 seconds)
- INR (International Normalized Ratio): A standardized ratio comparing your clotting time to normal (target varies by condition)
For patients NOT on blood thinners: Normal INR is 0.8-1.2 For patients ON warfarin: Target INR is typically 2.0-3.0 (or 2.5-3.5 for mechanical heart valves)
Who Should Consider This Test
Patients taking warfarin (Coumadin) or other vitamin K antagonists who need regular monitoring. Also useful for people with unexplained bleeding, easy bruising, frequent nosebleeds, or heavy menstrual periods. Commonly ordered before surgery to assess bleeding risk, or to evaluate liver function since the liver produces clotting factors.
Health Insights
Conditions Screened
Related Symptoms
When to Get Tested
No fasting required. If on warfarin, test at the same time of day relative to your dose for consistent results. Your doctor will advise on testing frequency - typically weekly when starting warfarin, then monthly once stable.
Understanding Your Results
For patients NOT on blood thinners:
- INR 0.8-1.2: Normal
- INR above 1.2: May indicate liver disease, vitamin K deficiency, or clotting factor issues
For patients ON warfarin:
- INR below 2.0: Blood may clot too easily (undertreated)
- INR 2.0-3.0: Therapeutic range for most conditions
- INR above 3.0: Increased bleeding risk (may need dose adjustment)
- INR above 4.0: Significantly elevated bleeding risk - contact your doctor
What to Expect
After placing your order, you'll receive an email from Rupa Health (our lab order partner) within 24 business hours to sign a consent form and schedule your blood draw at a Quest Diagnostics location.
The blood draw typically takes just a few minutes. Results are usually available within 1 business days and will appear in your secure Justlabs dashboard.
Our results include reference ranges and easy-to-understand indicators showing whether your values are within normal limits.
Frequently Asked Questions
$8
Typical hospital cash price: $120–$200
+ $28 in standard lab & physician fees at checkout (no additional bills later)
$18 lab collection + $10 physician order
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