Prothrombin Time (PT) is a test that measures how long it takes the liquid portion of blood (plasma) to clot. PT is an important measure to diagnose unexplained bleeding, especially when a patient is taking anticoagulants (blood thinners) like warfarin. PT is measured in seconds and usually provided as an International Normalized Ratio (INR).
For a healthy individual not using warfarin, the normal INR level ranges between 0.8 and 1.2. For those on warfarin, an INR ranging between 2.0 and 3.0 is usually viewed as the target range. A person’s INR may be higher, particularly for those with mechanical heart valves, so it is recommended to discuss your target INR level with your health provider.
PT tests are most accurately performed in clinical settings where plasma is separated from whole blood and mixed with calcium and tissue factor (a manufactured clotting agent). Tissue factors are assigned a mathematical value called the International Sensitivity Index (ISI) and vary by manufacturer. The ISI was developed to help create an international standard for measuring PT. INR is calculated by dividing a patient’s measured PT over a normal individual’s PT and raised to the power of the ISI.
Why knowing your INR is important?
A high INR indicates a higher risk of bleeding. An INR that’s lower than the targeted range suggests a higher risk of developing a clot. The purpose of taking warfarin is to thin blood enough to prevent deadly blood clots but maintain its ability to coagulate and prevent serious bleeding events. Doctors will track a patient’s INR to make adjustments to warfarin dosages. If patients on warfarin have their INR levels adjusted too high, they may be put at an unnecessary risk for a bleed out.
What medical conditions require warfarin and INR/PT testing?
Warfarin and other anticoagulants are typically used to treat medical conditions like atrial fibrillation, deep vein thrombosis, and pulmonary embolism. These conditions create blood clots which can travel to other parts of the body, such as the brain and lungs. Patients taking warfarin are subject to regular PT/INR testing to maintain their body’s ability to maintain proper blood clotting.
Alere INRatio PT/INR monitor system
The Alere INRatio PT/INR monitor system was developed and marketed as a convenient method of testing PT/INR levels from home. Consumers use the Alere INRatio monitor by putting a drop of blood onto a test strip and then feed that test strip into the INRatio monitor. The Alere INRatio then provides the consumer a digital reading of their PT/INR level.
Different factors can affect the accuracy of PT/INR readings when using the Alere INRatio INR/PT monitoring system. Certain medical conditions like anemia, unusual bleeding and bruising, conditions with elevated fibrinogen levels like arthritis, pneumonia, influenza, liver and kidney disease, severe infections, and late stage cancers can affect the accuracy of the Alere INRatio INR/PT monitor system. During December 2014, Alere issued a recall for patients with the previously-indicated medical conditions because the INRatio PT/INR monitor system may give readings significantly lower than they actually are, putting users at a greater risk for bleeding. The Food and Drug Administration (FDA) has designated this a Class I recall because of the likelihood of serious injury or death by consumers using this medical device.
Alere INRatio PT/INR injury claims
The Cochran Firm, D.C. is actively investigating injury claims arising from abnormally low INR readings provided by Alere INRatio PT/INR monitor systems. If you or a loved one suffered a serious injury, you may be entitled to substantial compensation. Because there are strict deadlines when filing an Alere INRatio PT/INR monitor claim, please contact us at your earliest convenience.
We offer free, prompt, and confidential case reviews and have a team of experienced and dedicated attorneys ready to help you recover damages for medical bills, lost wages, and pain and suffering. Call us at 1-800-THE-FIRM (843-3476) or fill out a contact form on our website. There are no fees unless we recover for you.
