Adreno Corticotrophic Hormone Plasma is a hormone made vasopressin that is created in the human's brain. The ADH is stored into the posterior pituitary gland. The vasopressin maintains the water level in blood and the quantity of water consumption from kidneys. The testing is all about examining the consumption level. The general percentage of water in blood is 1-5 pg/ml. The physician does ADH blood test and sees if the level is increased or decreased. The test is prescribed to watch the presence of the ADH hormone in kidneys and blood. ADH test specifies kidney or blood or it can be a combined one.