The Cavett blood test apparatus is a device used in medical diagnostic tests to measure blood coagulation time. It is named after the American physician, Richard H. Cavett, who developed the device in the mid-20th century. The apparatus consists of a cylindrical glass container, typically filled with a liquid such as sodium citrate, which is used to anticoagulate the blood sample.

The blood sample is placed in the apparatus and the time it takes for the blood to form a clot is measured. The test is commonly used to diagnose clotting disorders or to monitor the effectiveness of anticoagulant medications.

The Cavett blood test is a simple, inexpensive, and quick method for measuring coagulation time and is widely used in medical practice.