Lobular bleeding under the finger and toe nails is usually the result of trauma to the hand and is also a clinical sign of infective endocarditis. So, what tests should be done in patients with subungual bleeding of the finger and toe nails? The following is a brief description: 1. Doppler echocardiography, there are many red blood cells within the blood, which can reflect and scatter ultrasound and can be considered as a tiny source of sound. The probe is placed in the intercostal space without moving and emits ultrasound. When the red blood cells flow in the heart or large blood vessels, the sound frequency scattered by the red blood cells changes. As the red blood cells move toward the probe, the reflected sound frequency increases, and vice versa, decreases. This difference in sound frequency between the red blood cells and the probe in relative motion is called the Doppler shift. It can show the speed and direction of blood flow and the nature of blood flow. 2, two-dimensional echocardiography, also known as cross-sectionalechocardiography, referred to as two-dimensional ultrasound, the echo signal reflected back from the body in the form of light dots to form a cross-sectional image, also known as brightness modulation (Brightnessmode). It is a basic examination method that shows the morphology, spatial location and continuous relationship of each structure of the heart clearly, visually and in real time.