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Fibrinogen and Prothrombin Time Ratio (PTR) with Plasma

Published: August 9, 2026Updated: August 16, 2026

This test measures the ratio of fibrinogen levels and prothrombin time in your blood plasma to assess blood clotting function.

Quick summary

["Helps evaluate how well your blood is able to clot and identify potential bleeding or clotting disorders."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
48592-0
Short code
FSP Titr PPP LA
Synonyms
FSP Titr PPP LA
Category
coagulation
Sample
plasma
Container
Lavender-top (EDTA) or Green-top (Heparin)
Units
N/A
Ref low
0.8
Ref high
1.2
Critical range
— – 5 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
la
CPT
85610
SNOMED
396252006
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What This Test Measures

Fibrinogen is a protein essential for blood clot formation, while prothrombin time (PT) is a measure of how long it takes for blood to clot under specific conditions. This test combines these two factors to give a ratio that reflects your blood’s clotting efficiency.

Why It’s Done

Doctors may order this test if you have symptoms of bleeding disorders (like excessive bruising or nosebleeds), clotting disorders (such as deep vein thrombosis or stroke risk), or if you’re taking blood thinners. It can also be used to monitor treatment effectiveness.

Sample Collection and Preparation

A blood sample is drawn from a vein, usually in your arm. The blood is then processed to separate plasma, which is tested for fibrinogen and PT. This test does not require fasting.

Common Conditions Monitored

This test is particularly useful for diagnosing or monitoring conditions like liver disease (which affects fibrinogen production), vitamin K deficiency (which impacts prothrombin), or inherited clotting disorders.

Reference range

INR: 0.8-1.2 (warfarin: 2.0-3.0)N/A

Specimen: plasma

Inform your healthcare provider if you are taking blood thinners. No special preparation required.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

PTR (Plasma)

Frequently asked questions

What does a high or low PTR indicate?
A high PTR may suggest abnormal fibrinogen levels or prolonged PT, which could indicate liver disease, severe infection, or other conditions affecting clotting proteins. A low PTR might indicate excessive blood thinning (anticoagulant use) or deficiencies in clotting factors.
How often should I get this test?
Your doctor will determine how often this test is needed based on your medical history, current treatments, and symptoms. Regular monitoring may be required if you have chronic conditions like liver disease or are on blood thinners.
Can I eat or drink before this test?
No special preparation is needed for this test. You can eat and drink normally before your blood draw.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy