PT INR Test: Price, Purpose, Procedure and Normal Range

What is a prothrombin time test (PT/INR)?

A prothrombin time (PT) test measures the time to form a blood clot in a blood sample. The Coagulating or clotting factors are substances(proteins) that thicken the blood. Prothrombin is a coagulating factor. Our liver produces Prothrombin protein. When a person gets an injury or a cut that causes bleeding, clotting factors function together to form a blood clot. The low-level Clotting factor causes excessive and difficult to control bleeding after an injury. The high-level Clotting factors cause dangerous clot formation in your arteries or veins.

PT and INR meaning

The PT test results are expressed as INR calculations.  INR stands for the International normalised ratio (INR). INR test assesses the risk of bleeding or coagulation in the patients. 

Test details in brief

Also known as	Blood clotting test, PT Prothrombin Time.
Purpose	Blood clotting.
Preparation	No preparation is required.
Fasting	Need not fast.
Reporting time	24 hours.

PT INR test cost 

The test price depends on the diagnostic centre, city and home collection. However, generally, it would range from Rs 210 to 390.

Popular Lab	Price
Dr lalpathlab	Rs 350
City X-ray	Rs 280
Janta X-ray	Rs 270
Ganesh diagnostics	Rs 210
Mahajan Imaging	Rs 320
National Imaging	Rs 245
Prognosis laboratories	Rs 210

The table below lists the prices for popular diagnostic centres.

City	Price
PT INR test cost in Delhi	Rs 210 to 350
PT INR test cost in Gurgaon	Rs 270 to 350
PT INR test cost in Chandigarh	Rs 245 to 315
PT INR test cost in Chennai	Rs 270 to 350
PT INR test cost in Kolkata	Rs 250 to 350
PT INR test cost in Pune	Rs 252 to 330
PT INR test cost in Hyderabad	Rs 270 to 350
PT INR test cost in Mumbai	Rs 240 to 390

The purpose of the PT test

A PT/INR test has applications in

• For Detecting the efficacy of warfarin: Warfarin is an anticoagulant (a blood-thinning medicine) that treats and prevents dangerous blood clots. 
• Identifying the reason for abnormal blood clots:
• Identifying the underlying reason for abnormal bleeding: This may be the case in Thalassemia. 
• The PT test helps check clotting function before surgery for pre-surgery preparation to avoid complications. 
• Checking liver problems: The PT test comes under the liver function test and is thus helpful in determining liver health.
• Done in pair with a partial thromboplastin time (PTT) test: It is complementary to a partial thromboplastin time (PTT) test, which also checks blood clotting problems.

Symptoms of poor blood clotting.

• The Doctor prescribes the PT test after detecting the following symptoms. 
• Unexplained and easy Bruising: Bruising is skin discolouration due to tissue injury or blood vessel damage underneath the skin. 
• Heavy nose bleeding: It is the bleeding associated with the nostrils. The blood leaks from the nose. 
• More blood loss during menstrual periods: Excess blood loss in women during the menstrual phase. 

Clottings changes During pregnancy:

The changes in the Prothrombin level in pregnant women are depicted in the following table. 

Units	Non-pregnant adult	First trimester	second trimester	third trimester
Prothrombin plasma time (in seconds)	12.7 to 15.4	9.7 to 13.5	9.5 to 13.4	9.6 to 12.9

Normal Test ranges.

The table indicates the normal PT/INR Range values.

PT/INR Range	Result
Less than or equal to 1.1	Normal
More than 1.1	Above 1.1, your blood is clotting more slowly than normal
2.0 to 3.0	The general therapeutic range for people taking warfarin.

Reasons for high or low levels.

High levels: High PT/INR result indicates slow blood clotting slowly, and a greater risk of bleeding. It also signifies high warfarin levels or doses in the body.  

Low levels: Low PT/INR result indicates the insufficient dose of warfarin which prevents blood clotting. 

Role of vitamin K.

Vitamin K has a role in producing various blood clotting proteins. For, e.g. Prothrombin is a vitamin K-dependent protein and is directly involved in blood clotting. Vitamin K also makes Osteolactin, which is responsible for healthy bone tissue.

Sample Report.

The picture given below represents the sample report.

Calculation.

The WHO gives the standard calculation formula for finding INR. It is calculated as a ratio of the patient’s Prothrombin to a control Prothrombin standardised for the test. 

 INR = Patient PT ÷ Control PT.

What happens if it is high?

High PT/INR result indicates too slow blood clotting slowly, and a greater risk of bleeding. It also signifies high warfarin levels or doses in the body.  

Stroke, The lack of Prothrombin causes stroke in young children. This is because of the low function of the prothrombin gene. 

PT Test result

Case-1: If the patient is taking warfarin.

If you are taking warfarin, there would be two subcategories of results given below.

Low INR Levels: Risk for dangerous blood clots formation.

High INR levels: Risk for dangerous and excessive bleeding.

Case-2: If the patient is not taking warfarin.

The INR test ranges are referred to if the patients are not taking warfarin. Please refer to the normal ranges in this informative article. 

Our blood has many chemicals flowing in it. Some Chemicals have a clotting function. These functions are known as Clotting factors. There are various types of blood clotting factors like Factor I(fibrinogen), Factor II(Prothrombin), Factor III(Tissue Factor), etc.

How do you increase or decrease the blood clotting naturally?

Vitamins and food that increase blood clotting (Coagulation)

1. Vitamin K: Vitamin K increases the clotting in the patients. It thickens the blood and reduces the blood flowing capacity. 
2. Green vegetables: Vitamin K rich foods are spinach, cabbage, lettuce and broccoli. They are good for treating thin blood. 

Vitamins and food that decrease blood clotting (Coagulation)

1. Vitamin E: Vitamin E dissolves the clot, an anticoagulant(blood-thinning properties). Vitamin E prevents stroke and heart disease.
2. Almonds, Avocado, sunflower seeds and wheat germ oil are rich in Vitamin E . Ginger and turmeric also have anti-clotting properties.

Procedure: 

• The procedure involves using a blood sample that can be taken by your doctor or at a pathology lab. The procedure steps are:
• The technician would utilise a syringe for blood withdrawal. 
• The tube to be used for the blood sample collection shall be a blue colour tube.
• Calcium oxalate crystals prevent the clotting process from starting before the test in the blood sample. The blood cells are separated from the blood (plasma) by centrifugation. 
• The plasma is added to some source of Tissue Factor (e.g. thromboplastin from preserved brain tissue).
• The mixture is then warmed at 37°C for 2 minutes.
• Add to the mixture the Calcium chloride to neutralise the sodium citrate.
• Note the time from adding the calcium chloride until the plasma clots. 

Preparations for the PT test?

If the patients are already taking warfarin, they may need to delay their daily dose consumption until after the test.

The patients should consult their Doctor for any preparations. 

Frequently asked questions

References:

1. www.perinatology.com/Reference/Reference%20Ranges/Prothrombin%20time.htmhttp
2. my.clevelandclinic.org/health/diagnostics/17691-prothrombin-time-pt-test
3. www.testing.com/tests/prothrombin-time-and-international-normalized-ratio-ptinr/