Explained: INR, the blood test that NIA thought could be evidence of hawala

The NIA is investigating Malik over allegations of terrorist funding, and is understood to have suspected a reference to hawala dealings.

So what is the “INR” that Prof (Dr) Upendra Kaul, Padma Shri, was apparently asked about?

INR in medical parlance stands for ‘International Normalized Ratio’. It is a test of how efficiently an individual’s blood clots. It is closely related to a measure known as Standardized Prothrombin Time.

INR is a standardised number that the laboratory determines after testing the sample. Keeping a close watch on INR is especially important for patients who are administered oral blood thinners, commonly referred to as anti-clotting medicines or anticoagulants.

Prof Upendra Kaul called in J&K terror funding case.

In laboratory testing, an individual’s INR is determined from the results of the Prothrombin Time, or PT, test. This test measures the time it takes for a sample of an individual’s blood to clot. The INR is an internationally accepted standard for PT.

A blood thinner is a medicine that helps in the smooth flow of blood through the arteries and veins in the body, and prevents blood clots from forming, or existing blood clots from becoming bigger.

While these drugs are crucial to protect against the risk of heart attacks and strokes, they also cause an individual to bleed more than usual from cuts and bruises. But the benefits of these drugs are considered to outweigh this risk — provided careful monitoring is done using tests such as INR.

Commonly prescribed blood thinners include Apixaban, Dabigatran, Edoxaban, Heparin, and Warfarin. Patients who are prescribed a PT test to calculate INR are often also prescribed tests such as platelet count, fibrin D-dimer, and fibrinogen level.

Results of the PT/INR test vary on account of an individual’s age, gender, health history, medications, test method, etc. Since INR is a ratio, it is just a number, and does not have a unit. In general, the higher this number is for a particular individual, the longer it will take for their blood to clot.

A healthy person should have an INR of 1.1. And for a person on blood thinners, the INR should be between 2 and 3 in most cases. The goal INR will vary from patient to patient — it will be higher, for example, for an individual under treatment for a mechanical heart valve, than for a person with, say, a clot in their leg.

Malik has been Prof Kaul’s patient since 1996.

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