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Laboratory test

PT/INR Test (Prothrombin Time)

Explore the Prothrombin Time / INR test at PingMeDoc™ for blood counts, clotting or related blood assessments. Check the exact measurements, specimen type, preparation instructions, current price and report turnaround shown in the laboratory catalogue. Ask a doctor whether this test is appropriate for your symptoms or monitoring needs.

Also known as

PT INR Test · Prothrombin Time / International Normalised Ratio · Prothrombin Time · Protime · PT Test · INR Test · PT INR · Prothrombin time · Blood clotting time test

Sample
Blood
Fasting
Not required
Expected report time
Within 2 hours
Parameters
2

PT INR Test: quick answers

PT INR Test full form
Prothrombin Time / International Normalised Ratio
PT INR Test price
₹249, home sample collection
Normal range (adults)
PT (not on blood thinners): about 11 to 13.5 seconds; INR (not on blood thinners): about 0.8 to 1.2 more
Done for
Monitoring warfarin or acenocoumarol (blood thinners); Before surgery or a procedure; Unexplained bleeding or bruising
Fasting
Not required
Report
Within 2 hours

What is the PT INR Test?

The PT test measures how many seconds your blood plasma takes to clot. The INR is a standardised version of the same result, so it can be compared between laboratories. It is the main test used to monitor warfarin and acenocoumarol, and also reflects how well the liver makes clotting factors.

PT INR Test normal range

MeasurementTypical adult value
PT (not on blood thinners)about 11 to 13.5 seconds
INR (not on blood thinners)about 0.8 to 1.2
Usual INR target on warfarin2.0 to 3.0

Some conditions, such as certain mechanical heart valves, use a higher INR target set by the treating doctor. The PT seconds range depends on the reagent, which is why the INR is used for monitoring.

Ranges differ between laboratories and methods. The reference range printed on your own report is the one to read your result against.

What your PT INR Test result means

High INR on warfarin
The blood is thinner than intended, which raises bleeding risk. Do not change the dose yourself; contact the doctor who prescribes your blood thinner.
Low INR on warfarin
The blood is not as thin as intended, which may not protect against clots. Missed doses, diet changes and some medicines can cause this.
Prolonged PT without blood thinners
Can occur with liver disease, vitamin K deficiency, a lack of certain clotting factors or disseminated intravascular coagulation. Further tests usually follow.

One result is not a diagnosis. A doctor reads it with your symptoms, history, medicines and other tests.

Why is the PT INR Test done?

  • Monitoring warfarin or acenocoumarol (blood thinners)
  • Before surgery or a procedure
  • Unexplained bleeding or bruising
  • Checking liver function in liver disease
  • Suspected vitamin K deficiency

What does the PT/INR Test (Prothrombin Time) measure?

2 parameters. Expand a group to see the measurements, units and available method details.

Other measurements2 parameters
ParameterUnitLOINC
Prothrombin Time (PT)sec5902-2
International Normalised Ratio (INR)ratio6301-6

The reference interval printed on your actual laboratory report governs interpretation. Intervals can vary by laboratory, method, age, sex and pregnancy. Methods can also vary by processing laboratory.

PT INR Test: sample & preparation

Sample: Blood. Fasting: Not required.

  • No fasting is needed. Tell the lab about any blood-thinning medicines (such as warfarin or aspirin) you are taking, as these affect the result.

Frequently asked questions

What is a PT INR test?
PT is the prothrombin time, the number of seconds blood takes to clot in the test. INR is the international normalised ratio, a calculation that makes the result comparable between labs. People on warfarin are monitored with the INR.
What is the normal INR?
For a person not taking blood thinners, the INR is usually around 0.8 to 1.2. For most people on warfarin the target is 2.0 to 3.0, but your doctor sets your own target.
Is fasting needed for the PT INR test?
No fasting is needed. If you take warfarin, take it as usual unless your doctor says otherwise, and keep your diet steady, as large changes in green leafy vegetables can affect the INR.
Is protime the same as prothrombin time?
Yes. Protime and pro time are short names for prothrombin time. They are the same test.
How often should the INR be checked on warfarin?
When warfarin is started or the dose changes, the INR is checked often, sometimes every few days. Once it is stable, many people are checked every few weeks. Your doctor decides the schedule.
How much does the Prothrombin Time / INR cost?
The current online price is ₹249, with MRP ₹1,119. Review your booking total before payment.
Can I book this test for home collection?
Yes. Add your collection address and choose an available collection slot at checkout.
When is the report expected?
The catalogue lists Within 2 hours. Confirm the collection and report schedule with the booking team.
Can I book this with other tests?
You can add available tests to the same cart. Review the combined preparation instructions and collection requirements with the booking team.

Sources: British Society for Haematology: Guidelines on oral anticoagulation with warfarin, 4th edition (Keeling et al., 2011); American College of Chest Physicians (CHEST): Antithrombotic therapy guidelines. General information, not medical advice.

This page gives catalogue facts only (sample, preparation, report time) and has not been reviewed by a doctor. It is general information, not a diagnosis or advice for you: your doctor decides which tests you need and what the results mean.

Book the PT/INR Test (Prothrombin Time)

2 parameters · No fasting required · Report time: Within 2 hours

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