No fasting is required prior to this test. The test evaluates how your body processes sugar. A high level in your blood may indicate your body is not processing sugar effectively (positive test). If the results of this screen are positive, the woman may have the Glucose Tolerance Test performed.
A valve is a mechanism that opens and closes to control the flow of fluids. In a scientific context, fluids include both liquids and gases â any substance that can flow freely â and valves may use either. Valves control fluid flow in motors, plumbing, irrigation, pneumatic and hydraulic systems.
A valve that is diseased or damaged can affect the flow of blood through the heart. There are two main types of valve problem: 1  Valve stenosis. 2  This means that the opening of the valve is narrowed and the valve does not open fully.