Nitrogen, Total, Urine
Method Description Describes how the test is performed and provides a method-specific reference
The Nitrogen analyzer utilizes the Dumas combustion method of determining total nitrogen in urine. 0.5 mL of urine is added to 0.1 grams of sucrose in a tin capsule, which is blanked with oxygen prior to hermetic sealing to exclude atmospheric nitrogen interference. The capsule is then placed in the instrument, combusted, and oxidized at 960 degrees C. Nitrogen in the form of nitric oxide is released from the specimen and is carried by carbon dioxide through a column containing tungsten that reduces the nitric oxide to molecular nitrogen. Nitrogen is detected using a thermal conductivity detector and response is compared to standards of known nitrogen concentration for quantitation. Complete analysis time is 4.0 minutes per specimen.(Ward JN, Kloke KM, Chezick PA, et al: Rapid accurate quantitation of nitrogen in urine and feces using the Elementar Rapid NIII analyzer. Clin Chem 2002;48[S6]:A71)
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.
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