Hypotonic hyponatremia dramatic increase the serum sodium concentration and place the patient at risk for so-called "central pontine myelinolysis" (CPM). That disorder is characterized by major neurologic damage, often of a permanent nature. Because of the risk of CPM, people with low volume hyponatremia may eventually require water infusion as well as volume replacement. Doing so lessens the chance of a too rapid increase of the serum sodium level as blood volume rises and ADH levels fall. In people who are volume depleted, i.e., their blood volume is too low, ADH secretion is increased, since volume depletion is a potent stimulus for
Serum-separating tube particles to cause blood to clot quickly. The blood sample may then be centrifuged, allowing the clear serum to be removed for testing. These tubes should be used with care when measuring drug or hormone levels because the drug or hormone may diffuse from the serum into the gel, causing a reduction in measured level. The gel in SST II tubes (which appears slightly less opaque) is supposed to have less effect on drug levels in serum. Serum-separating tube Serum-separating tubes, also known as serum separator tubes or SSTs, are used in medical clinical chemistry tests requiring blood serum. SSTs