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.
Cross section showing the water table varying with surface topography as well as a perched water table. The water table is the upper surface of the zone of saturation. The zone of saturation is where the pores and fractures of the ground are saturated with water. The water table is the surface where the water pressure head is equal to the atmospheric pressure (where gauge pressure = 0). It may be visualized as the surface of the subsurface materials that are saturated with groundwater in a given vicinity.