Portable coagulation monitoring devices, systems, and methods are disclosed. Namely, a test cartridge is provided for use in a portable coagulation monitor (PCM) device. Further, the test cartridge comprises two glass-filled thermoplastic polymer plates and a disposable blood introduction device. The two glass-filled thermoplastic polymer plates are arranged substantially in parallel with a small gap therebetween for receiving a sample of blood to be tested. Using the PCM device, the two glass-filled thermoplastic polymer plates can be moved linearly relative to each other. Methods of measuring coagulation response in a blood sample using the test cartridge and the PCM device are provided. A method of introducing blood into the test cartridge using the disposable blood introduction device is provided.