1 Why the test is used: Between 75% and 90% of people with lupus have a positive anti-dsDNA test. 2  Also, the test is very specific for lupus. 3  Therefore, a positive test can be useful in confirming a diagnosis. 4  For many people, the titer, or level, of the antibodies rises as the disease becomes more active.
The zone below ground where the pore spaces are filled with ground water is called the saturated zone. Above the saturated zone, where the pore spaces are not filled with ground water, is the unsaturated zone. The water table marks the boundary between the saturated and unsaturated zone. The water table intersects Earth's surface at rivers and at lakes.
The depth to the water table varies. In some settings, it can be at or near the land surface; for example, near bodies of surface water in humid climates. In other settings, the depth to the water table can be hundreds of feet below land surface. Ground water commonly is an important source of surface water.