Prothrombin Time with INR

Quest Diagnostics

Sample type: Plasma

Requires fasting: No

Phlebotomy required

Details

This test is often recommended for individuals who are on Warfarin therapy or those who may have symptoms or a family history of clotting disorders.

Biomarker summary

INR
Prothrombin Time (PT)

Additional details

Estimated days for results: Results should be available in 2 - 5 business days after the sample is collected

Details

Prothrombin Time with INR - This test is used to check for problems with blood clotting and to monitor the effectiveness of Warfarin therapy, a medication that prevents blood clots. It's particularly useful for people with hereditary or acquired clotting disorders. The test focuses on the extrinsic pathway, one of the body's methods for forming blood clots.

What patients is this test right for?

This test is often recommended for individuals who are on Warfarin therapy or those who may have symptoms or a family history of clotting disorders.

What type of sample is required for this test?

One full unopened 3.2% sodium citrate (light blue-top) tube is needed for this test.

Test Resources http://education.questdiagnostics.com/faq/FAQ104

Average sample processing time

2–4 business days

Reference range

INR
≤3 months Not established
>3 months
Reference range 0.9-1.1
Moderate-intensity Warfarin therapy 2.0-3.0
Higher-intensity Warfarin therapy 3.0-4.0

PT
≤3 months Not established
>3 months 9.0-11.5 sec

Flagging not provided. Pediatric reference intervals have not been established. Based on published literature, the adult reference interval (9.0-11.5 seconds) is generally applicable down to approximately 3 months of age with younger patients having a slightly higher upper limit by several seconds. Warfarin Therapeutic INR Range: 2.0 - 3.0

Health categories

Hematology

Patient instructions

Blood Draw Options with Fullscript
Fullscript offers several convenient phlebotomy options to complete your lab testing:

Quest Diagnostics Patient Service Centers (PSC)

Location: Visit a nearby Quest Diagnostics Patient Service Center.
Cost: $10 sample collection fee (paid during lab order checkout).
Scheduling: Schedule your appointment here. Appointments are recommended to reduce wait times. Walk-ins are accepted, but may experience delays. Aim to arrive 10 minutes before your appointment.
Collection Instructions:

Bring a valid ID.
Bring your digital or printed requisition form, available in the Labs tab of your Fullscript account.

Check-in: Scan the QR code from your confirmation email or follow kiosk instructions.
More Info: Quest Diagnostics blood draw guide

Getlabs Mobile Phlebotomy

Location: Sample collection at your home or office.
Cost: $85 sample collection fee (paid during lab order checkout).
Availability: Available in most locations – enter your ZIP code during checkout to confirm.
Scheduling: Schedule your appointment here through your Fullscript account.
Collection Instructions:

Have your digital or printed requisition form and valid ID ready.
Your phlebotomist will contact you by phone to coordinate arrival.

More Info: Getlabs blood draw guide

In-office phlebotomy instructions

Specimen

Preferred Specimen(s): One full unopened 3.2% sodium citrate (light blue-top) tube
Alternative: NA
Minimum Volume: NA
Collection Instructions: NA

Storage and shipping instructions