Test ID: UOSMB
Osmolality, Body Fluid
Secondary ID 
A test code used for billing and in test definitions created prior to November 2011
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Useful For Suggests clinical disorders or settings where the test may be helpful
To help determine the source and type of fluid
Method Name A short description of the method used to perform the test
Freezing Point Depression
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Aliases Lists additional common names for a test, as an aid in searching
Specimen Type Describes the specimen type needed for testing
Specimen Required Defines the optimal specimen. This field describes the type of specimen required to perform the test and the preferred volume to complete testing. The volume allows automated processing, fastest throughput and, when indicated, repeat or reflex testing.
Collection Container/Tube: Sterile container
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions: Centrifuge to remove any cellular material.
Additional Information: Indicate specimen source.
Specimen Minimum Volume Defines the amount of specimen required to perform an assay once, including instrument and container dead space. Submitting the minimum specimen volume makes it impossible to repeat the test or perform confirmatory or perform reflex testing. In some situations, a minimum specimen volume may result in a QNS (quantity not sufficient) result, requiring a second specimen to be collected.
Reject Due To Identifies specimen types and conditions that may cause the specimen to be rejected
| Hemolysis | NA |
| Lipemia | NA |
| Icterus | NA |
| Other | NA |
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
| Specimen Type | Temperature | Time |
|---|---|---|
| Body Fluid | Frozen (preferred) | 7 days |
| Refrigerated | 7 days |
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Osmolality is an index of the solute concentration. It is determined by the number and not by the nature of the particles in solution. Dissolved solutes change the physical properties of solutions; they increase the osmotic pressure and decrease freezing point.
Body fluids have the same osmolality as a corresponding serum specimen taken at the same time. "True body fluids" include: ascitic, cerebrospinal, hydrocele, edema, pericardial, pleural, spermatocele and synovial fluids. Secretions not in equilibrium with the extra-cellular fluids of the body include gastric juice, saliva and sweat.
Serum osmolality is normally between 275 mOsm/kg to 295 mOsm/kg; it increases with dehydration and decreases with overhydration. Urine osmolality reflects the ability of the kidney to maintain tonicity and water balance. The normal kidney can concentrate a urine to 800 mOsm/kg to 1,400 mOsm/kg, and with excess fluid intake, a minimal osmolality of 40 mOsm/kg to 80 mOsm/kg can be obtained.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
No established reference values
Interpretation Provides information to assist in interpretation of the test results
No normals are available.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Avoid viscous fluids
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
Clinic Diagnosis and Management by Laboratory Methods. 20th edition. Edited by JB Henry. Philadelphia, WB Saunders Company, 2001
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. (In Clinical Diagnosis and Management by Laboratory Methods. 20th edition. Edited by JB Henry. Philadelphia, PA, WB Saunders Company, 2001)
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.
Maximum Laboratory Time Defines the maximum time from specimen receipt at Mayo Medical Laboratories until the release of the test result
Specimen Retention Time Outlines the length of time after testing that a specimen is kept in the laboratory before it is discarded
Performing Laboratory Location The location of the laboratory that performs the test
CPT Code Information Provides guidance in determining the appropriate Current Procedural Terminology (CPT) code(s) information for each test or profile. The listed CPT codes reflect Mayo Medical Laboratories interpretation of CPT coding requirements. It is the responsibility of each laboratory to determine correct CPT codes to use for billing.
83930
LOINC® Code Information Provides guidance in determining the Logical Observation Identifiers Names and Codes (LOINC) values for the result codes returned for this test or profile.
| Result ID | Reporting Name | LOINC Code |
|---|---|---|
| OSBF | Osmolality, BF | 15200-9 |
| FLD6 | Fluid Type | 14725-6 |
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