Design,Development and Testing of Activated Partial Thromboplastin Time Device

Abstract

While newer, advanced medical equipment are available for testing of biological symptoms such as Pregnancy test, Cholesterol test, HIV test, Allergy test, Drug and alcohol test etc, very little research exists on the measurement of Activated partial thromboplastin time (APTT) value with force as a key parameter for testing. APTT is actually a blood coagulation test prescribed by the doctor in order to measure clotting time ofan individual patient. Thus, APTT test will look at how good this clotting factor are working by measuring the time taken by the clotting factors of blood to initiate clotting procedure. Currently, there are few commercial devices available for APTT testing, but with high cost. Thus, the present work targets to design and fabricate a prototype based on the principle of Pinching with accuracy and precision. So, two prototypes named prototype I and prototype II were designed and fabricated. Both prototype involves components like cam, loadcell, spring, motor and electrical circuits. The prototype I was failure as it caused vibration, instability due to its large dimensions. Thus, prototype II was fabricated with modification and blood was tested in the prototype II to obtain APTT value. Thus, around 15 experiments were carried out on the proposed prototype with two methodology; (a) with blood plasma, (b) with whole blood. The variation of force with time is analyzed, although no variation of force with time is seen with methodology (a) but the variation is found in methodology (b). The major findings of the experiment were as follow; Force range: 425 to 465 grams; Time range: 0-90 second; Operation time at maximum force = 68 second. Thus, time (t) at which, the force value started to become stable is the actual reference time value of APTT and it was 68 seconds for the tested blood sample. Although, there is a need to assess the device performance for its repeatability and variation of force vs. time in different blood groups, age groups and also by applying different activating reagent to whole blood. The prototype II cost is found substantially lower than other devices available in the market to measure APTT.