BACK TOTOP Browse A-ZSearchBrowse A-ZABCDEFGHIJKLMNOPQRSTUVWXYZ0-9 E-mail FormEmail ResultsName:Email address:Recipients Name:Recipients address:Message: Print-FriendlyBookmarksbookmarks-menuOsmolality blood testOsmolality blood test is a test that measures the concentration of all chemical particles found in the fluid part of blood.Osmolality in the urine can be measured with a urine test.Urine testThe osmolality urine test measures the concentration of chemicals in urine. Osmolality in the blood can be measured using a blood test.ImageRead Article Now Book Mark Article How the Test is Performed A blood sample is needed. Blood sample is neededVenipuncture is the collection of blood from a vein. It is most often done for laboratory testing.ImageRead Article Now Book Mark Article How to Prepare for the Test Follow any instructions from your health care provider about not eating before the test. Your provider may tell you to temporarily stop taking any medicines that may interfere with test results. Such medicines may include water pills (diuretics). How the Test will Feel When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging sensation. Afterward, there may be some throbbing or a slight bruise. This soon goes away. Why the Test is Performed This test helps check your body's water balance. Your provider may order this test if you have signs of any of the following:Low sodium (hyponatremia) or water loss Low sodiumLow blood sodium is a condition in which the sodium level in the blood is lower than normal. The medical name of this condition is hyponatremia....Read Article Now Book Mark Article Poisoning from harmful substances such as ethanol, methanol, or ethylene glycol EthanolEthanol poisoning is caused by drinking too much of the alcohol found in alcoholic beverages. This article is for information only. DO NOT use it to...Read Article Now Book Mark Article MethanolMethanol is a nondrinking type of alcohol used for industrial and automotive purposes. This article discusses poisoning from an overdose of methanol...Read Article Now Book Mark Article Ethylene glycolEthylene glycol is a colorless, odorless, sweet-tasting chemical. It is poisonous if swallowed. Ethylene glycol may be swallowed accidentally, or it...ImageRead Article Now Book Mark Article Problems producing urine Excessive thirst Excessive urinationIn healthy people, when osmolality in the blood becomes high, the body releases antidiuretic hormone (ADH).Antidiuretic hormoneAntidiuretic blood test measures the level of antidiuretic hormone (ADH) in blood.Read Article Now Book Mark Article This hormone causes the kidneys to reabsorb water. This results in more concentrated urine. The reabsorbed water dilutes the blood. This allows blood osmolality to fall back to normal.Low blood osmolality suppresses ADH. This reduces how much water the kidneys reabsorb. Dilute urine is passed to get rid of the excess water, which increases blood osmolality back toward normal. Normal Results Normal values range from 275 to 295 mOsm/kg (275 to 295 mmol/kg).Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your provider about the meaning of your specific test results. What Abnormal Results Mean A higher than normal osmolality may be due to:Diabetes insipidus Diabetes insipidusDiabetes insipidus (DI) is an uncommon condition in which the kidneys are unable to prevent the excretion of water. DI is not the same as diabetes me...ImageRead Article Now Book Mark Article High blood sugar level (hyperglycemia) High blood sugar levelA blood sugar test measures the amount of a sugar called glucose in a sample of your blood. Glucose is a major source of energy for most cells of the...ImageRead Article Now Book Mark Article High level of nitrogen waste products in the blood (uremia) UremiaPrerenal azotemia is an abnormally high level of nitrogen waste products in the blood.ImageRead Article Now Book Mark Article High sodium level (hypernatremia) Stroke or head trauma resulting in decreased ADH secretion StrokeA stroke occurs when blood flow to a part of the brain stops. A stroke is sometimes called a "brain attack. " If blood flow is cut off for longer th...ImageRead Article Now Book Mark Article Water loss (dehydration) Water lossDehydration occurs when your body does not have as much water and fluids as it needs. Dehydration can be mild, moderate, or severe, based on how much...ImageRead Article Now Book Mark Article A lower than normal osmolality may be due to:ADH oversecretion Adrenal gland not working normally Conditions linked to lung cancer (causing syndrome of inappropriate ADH production, or SIADH) Lung cancerSmall cell lung cancer (SCLC) is a fast-growing type of lung cancer. It spreads much more quickly than non-small cell lung cancer. There are two typ...ImageRead Article Now Book Mark Article SIADHSyndrome of inappropriate antidiuretic hormone secretion (SIADH) is a condition in which the body makes too much antidiuretic hormone (ADH). ADH is ...Read Article Now Book Mark Article Other conditions or medicines that cause SIADH Drinking too much water or fluid Low sodium level (hyponatremia) Underactive thyroid gland (hypothyroidism)HypothyroidismHypothyroidism is a condition in which the thyroid gland does not make enough thyroid hormone. This condition is often called underactive thyroid....ImageRead Article Now Book Mark Article Risks There is little risk involved with having your blood taken. Veins and arteries vary in size from one person to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.Other risks associated with having blood drawn are slight but may include:Excessive bleeding Fainting or feeling lightheaded Multiple punctures to locate veins Blood accumulating under the skin (hematoma) Infection (a slight risk any time the skin is broken) Open ReferencesReferencesOh MS, Briefel G, Pincus MR. Evaluation of renal function, water, electrolytes, and acid-base balance. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 15.Verbalis JG. Disorders of water balance. In: Yu ASL, Chertow GM, Luyckx VA, Marsden PA, Skorecki K, Taal MW, eds. Brenner and Rector's The Kidney. 11th ed. Philadelphia, PA: Elsevier; 2020:chap 15.AllVideoImagesTogBlood test - illustration Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.Blood testillustrationBlood test - illustration Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.Blood testillustration Tests for Osmolality blood test Osmolality blood testOsmolality urine testUrine specific gravity testRelated Information Dehydration(Condition)Antidiuretic hormone blood test(Medical Test)Diabetes insipidus(Condition)Blood sugar test(Medical Test)Sodium blood test(Medical Test)Acute tubular necrosis(Condition)Stroke(Condition)Prerenal azotemia(Condition)Low blood sodium(Condition)Lung cancer - small cell(Condition)Stroke - InDepth(In-Depth) Review Date: 8/20/2023 Reviewed By: Jacob Berman, MD, MPH, Clinical Assistant Professor of Medicine, Division of General Internal Medicine, University of Washington School of Medicine, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team. The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. No warranty of any kind, either expressed or implied, is made as to the accuracy, reliability, timeliness, or correctness of any translations made by a third-party service of the information provided herein into any other language. © 1997- A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited. © 1997- All rights reserved. A.D.A.M. content is best viewed in IE9 or above, Firefox and Google Chrome browser.Content is best viewed in IE9 or above, Firefox and Google Chrome browser.
Osmolality blood testOsmolality blood test is a test that measures the concentration of all chemical particles found in the fluid part of blood.Osmolality in the urine can be measured with a urine test.Urine testThe osmolality urine test measures the concentration of chemicals in urine. Osmolality in the blood can be measured using a blood test.ImageRead Article Now Book Mark Article How the Test is Performed A blood sample is needed. Blood sample is neededVenipuncture is the collection of blood from a vein. It is most often done for laboratory testing.ImageRead Article Now Book Mark Article How to Prepare for the Test Follow any instructions from your health care provider about not eating before the test. Your provider may tell you to temporarily stop taking any medicines that may interfere with test results. Such medicines may include water pills (diuretics). How the Test will Feel When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging sensation. Afterward, there may be some throbbing or a slight bruise. This soon goes away. Why the Test is Performed This test helps check your body's water balance. Your provider may order this test if you have signs of any of the following:Low sodium (hyponatremia) or water loss Low sodiumLow blood sodium is a condition in which the sodium level in the blood is lower than normal. The medical name of this condition is hyponatremia....Read Article Now Book Mark Article Poisoning from harmful substances such as ethanol, methanol, or ethylene glycol EthanolEthanol poisoning is caused by drinking too much of the alcohol found in alcoholic beverages. This article is for information only. DO NOT use it to...Read Article Now Book Mark Article MethanolMethanol is a nondrinking type of alcohol used for industrial and automotive purposes. This article discusses poisoning from an overdose of methanol...Read Article Now Book Mark Article Ethylene glycolEthylene glycol is a colorless, odorless, sweet-tasting chemical. It is poisonous if swallowed. Ethylene glycol may be swallowed accidentally, or it...ImageRead Article Now Book Mark Article Problems producing urine Excessive thirst Excessive urinationIn healthy people, when osmolality in the blood becomes high, the body releases antidiuretic hormone (ADH).Antidiuretic hormoneAntidiuretic blood test measures the level of antidiuretic hormone (ADH) in blood.Read Article Now Book Mark Article This hormone causes the kidneys to reabsorb water. This results in more concentrated urine. The reabsorbed water dilutes the blood. This allows blood osmolality to fall back to normal.Low blood osmolality suppresses ADH. This reduces how much water the kidneys reabsorb. Dilute urine is passed to get rid of the excess water, which increases blood osmolality back toward normal. Normal Results Normal values range from 275 to 295 mOsm/kg (275 to 295 mmol/kg).Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your provider about the meaning of your specific test results. What Abnormal Results Mean A higher than normal osmolality may be due to:Diabetes insipidus Diabetes insipidusDiabetes insipidus (DI) is an uncommon condition in which the kidneys are unable to prevent the excretion of water. DI is not the same as diabetes me...ImageRead Article Now Book Mark Article High blood sugar level (hyperglycemia) High blood sugar levelA blood sugar test measures the amount of a sugar called glucose in a sample of your blood. Glucose is a major source of energy for most cells of the...ImageRead Article Now Book Mark Article High level of nitrogen waste products in the blood (uremia) UremiaPrerenal azotemia is an abnormally high level of nitrogen waste products in the blood.ImageRead Article Now Book Mark Article High sodium level (hypernatremia) Stroke or head trauma resulting in decreased ADH secretion StrokeA stroke occurs when blood flow to a part of the brain stops. A stroke is sometimes called a "brain attack. " If blood flow is cut off for longer th...ImageRead Article Now Book Mark Article Water loss (dehydration) Water lossDehydration occurs when your body does not have as much water and fluids as it needs. Dehydration can be mild, moderate, or severe, based on how much...ImageRead Article Now Book Mark Article A lower than normal osmolality may be due to:ADH oversecretion Adrenal gland not working normally Conditions linked to lung cancer (causing syndrome of inappropriate ADH production, or SIADH) Lung cancerSmall cell lung cancer (SCLC) is a fast-growing type of lung cancer. It spreads much more quickly than non-small cell lung cancer. There are two typ...ImageRead Article Now Book Mark Article SIADHSyndrome of inappropriate antidiuretic hormone secretion (SIADH) is a condition in which the body makes too much antidiuretic hormone (ADH). ADH is ...Read Article Now Book Mark Article Other conditions or medicines that cause SIADH Drinking too much water or fluid Low sodium level (hyponatremia) Underactive thyroid gland (hypothyroidism)HypothyroidismHypothyroidism is a condition in which the thyroid gland does not make enough thyroid hormone. This condition is often called underactive thyroid....ImageRead Article Now Book Mark Article Risks There is little risk involved with having your blood taken. Veins and arteries vary in size from one person to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.Other risks associated with having blood drawn are slight but may include:Excessive bleeding Fainting or feeling lightheaded Multiple punctures to locate veins Blood accumulating under the skin (hematoma) Infection (a slight risk any time the skin is broken) Open ReferencesReferencesOh MS, Briefel G, Pincus MR. Evaluation of renal function, water, electrolytes, and acid-base balance. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 15.Verbalis JG. Disorders of water balance. In: Yu ASL, Chertow GM, Luyckx VA, Marsden PA, Skorecki K, Taal MW, eds. Brenner and Rector's The Kidney. 11th ed. Philadelphia, PA: Elsevier; 2020:chap 15.