Osmolality (Blood) Test

Osmolality is the increment and decreasing of blood due to dehydration and Overhydration of one's body. In a normal person, high levels of osmolality in blood can simulate antidiuretic hormone (ADH) secretion. This results in less concentrated blood plasma, high concentrated urine and increased water reabsorption. Osmolality is actually the measuring of one substance ability to dissolve in another substance. The greater the concentration, the higher level of osmolality. Salty water has a very high osmolality level compared to water with a pinch of salt. The body's functional ability makes specific adjustments hence, is able to release and maintain adequate osmolality levels. In fact, even you can know the level yourself. If you are urinating frequently, consider your osmolality level is low. This is the body's way to get rid of excess water and maintain the osmolality levels. The osmolality test is also called the serum osmolality test as Serum is the liquid part of blood.

To get a blood osmolality test, blood sample is required hence, your doctor will write you a lab osmolality blood test prescription and tell you to go to the laboratory. For the test, preference is to fast at least six hours before blood test. In some cases, you may have to restrain yourself from drinking liquid as well. Some medications like mannitol are known to interfere with the blood report, therefore you might have to avoid the medication as well. Yes, if you cannot miss them, then your doctor will guide you accordingly. Therefore, it's vital to inform your doctor of any medication you are taking, even over the counter medications.

This test is usually ordered to check your body's water/salt levels. This helps in verifying if you are having a medical condition of concern or not. This test is used for people having the following symptoms: Dehydration Excess of sodium in your bloodstream Hyponatremia- deficiency of sodium in blood Certain substance poisoning like, methanol, ethanol or ethylene glycol etc.

A trained medical technician will draw a blood sample at either the laboratory or at the doctor's office. A needle is used to draw blood, usually from your arm's vein. First, the area will be cleaned with antiseptic and then an elastic band will be tied around your arm to gather blood. A needle is inserted into a vein and required amount of blood is withdrawn into a vial. On collection of required amount of blood, the technician will remove the band and clean the site needle was inserted. If required, will apply a bandage as well. The sample is then taken to the laboratory.