The microINR® Coagulation Meter is a device designed for the measurement of INR levels. Regular INR monitoring is essential for patients undergoing oral anticoagulant therapy based on vitamin K antagonists. The system quantitatively determines prothrombin time from a fresh capillary blood sample and calculates the INR value. It is an in vitro diagnostic device suitable for both home self-testing and professional use.
The measurement principle of the microINR system is based on a microfluidic rapid test, where the device directly determines the prothrombin time using an image processing algorithm, from which it calculates the INR value.
The microfluidic cartridge used for the test, called the Chip, forms the basis of the system’s measurement principle. During sample application, blood travels through microreactors treated with thromboplastin to reach the left and right capillaries. The left capillary serves as the control, while the right is the measurement channel, as shown in the figure below.
The measurement principle of the microINR system is based on a microfluidic rapid test, where the device directly determines the prothrombin time using an image processing algorithm, from which it calculates the INR value.
The microfluidic cartridge used for the test, called the Chip, forms the basis of the system’s measurement principle. During sample application, blood travels through microreactors treated with thromboplastin to reach the left and right capillaries. The left capillary serves as the control, while the right is the measurement channel, as shown in the figure below.
The sample is applied to the Chip through the entry channel. After the entry channel, the sample splits and reaches the capillaries through the microreactors.
Sample propagation in the Chip’s microreactors and capillaries (left side: control channel, right side: measurement channel).
The filled capillary length is proportional to the square root of elapsed time, thus the clotting time can be calculated.
The prothrombin time (PT) is calculated from the second derivative of the length change function. This method allows a precise determination of clotting time, and an advantage of the evaluation is that sample properties (e.g., viscosity) do not affect the measurement.
The flow of the sample through the Chip’s capillaries can be described by the following mathematical equations.
The INR is calculated using the formula below:
In the formula, PT (Prothrombin Time) is the prothrombin time calculated during the sample analysis, ISI (International Sensitivity Index) is a sensitivity index characteristic of the test, and MNPT (Mean Normal Prothrombin Time) is the average prothrombin time from samples selected from a healthy population, based on a specific measurement method.
The data matrix on the Chip contains the MNPT and ISI values, as well as the test LOT identifier and expiration date.
3 μL fresh capillary blood
199 results
2800 mAh
70 tests
(factory calibrated)
Automatic chip LOT coding
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