UOSMB - Performance: Osmolality, Body Fluid

Test Catalog

Test Name

Test ID: UOSMB    
Osmolality, Body Fluid

Method Description Describes how the test is performed and provides a method-specific reference

Measurement of the freezing point of urine is the most widely used principle in osmometers. The extent of lowering below 0 degrees C (the freezing point of water) is a function of the concentration of substances dissolved in the urine. By definition, 1 milliosmole per kilogram lowers the freezing point 0.001858 degrees C. It has been observed that one may cool water to as low as -40 degrees C and still have liquid water provided that no ice crystals, dust, or other contaminants are present, and that the water is not agitated (super-cooling). Vigorous agitation results in rapid freezing of the super-cooled solution (seeding). When the solution freezes, it quickly warms to its freezing point and the temperature remains constant for a relatively long period of time.(Clinical Diagnosis and Management by Laboratory Methods. 20th edition. Edited by JB Henry. Philadelphia, PA, WB Saunders Company, 2001)

PDF Report Indicates whether the report includes an additional document with charts, images or other enriched information


Day(s) and Time(s) Test Performed Outlines the days and times the test is performed. This field reflects the day and time the sample must be in the testing laboratory to begin the testing process and includes any specimen preparation and processing time required before the test is performed. Some tests are listed as continuously performed, which means assays are performed several times during the day.

Monday through Sunday; Continuously

Analytic Time Defines the amount of time it takes the laboratory to setup and perform the test. This is defined in number of days. The shortest interval of time expressed is "same day/1 day," which means the results may be available the same day that the sample is received in the testing laboratory. One day means results are available 1 day after the sample is received in the laboratory.

Same day/1 day

Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result

1 day

Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded

7 days

Performing Laboratory Location The location of the laboratory that performs the test