Nitrogen, Total, 48, 72, or 96 Hours, Feces
NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.
Assessing nutritional status (protein malnutrition), evaluating protein catabolism, and determining nitrogen balance, when used in conjunction with 24-hour urine nitrogen measurement
Special Instructions and Forms Describes specimen collection and preparation information, test algorithms, and other information pertinent to test. Also includes pertinent information and consent forms to be used when requesting a particular test
Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name
Nitrogen, Total 48/72/96 Hr, F
Nitrogen, Total, 48- or 72-Hours, Feces
Nitrogen, Total, 48/72/96-Hr, Feces
Nitrogen, Total, 48- or 72-Hours, Feces
Nitrogen, Total, 48/72/96-Hr, Feces
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.
Container/Tube: Stool container (Supply T291)
Specimen Volume: Entire 24-, 48-, 72-, or 96-hour collection
1. Specimen submitted must contain at least 10 g of feces.
2. See Stool Collection Information Sheet in Special Instructions.
1. Length of collection period is required.
2. Barium and boric acid interfere with test procedure.
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.
20 g of homogenate
Specimen Stability Information Provides a description of the temperatures required to transport a specimen to the laboratory. Alternate acceptable temperature(s) are also included.
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
Nitrogen is a key component of proteins. During protein catabolism (proteolysis), nitrogen is excreted in the urine and feces. Protein catabolism may be increased after stress (eg, physical trauma, surgery, infections, burns).
"Nitrogen balance" is the difference between the amount of nitrogen ingested and the amount excreted. A patient who is in negative nitrogen balance is using muscle protein to meet the metabolic requirements of the body and is, therefore, in a catabolic state.
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.
<16 years: not established
> or =16 years: 1-2 g/24 hours
Average fecal nitrogen excretion is approximately 2 g/day, but fecal nitrogen excretion is highly variable, especially in conditions resulting in excessive protein catabolism. Significantly abnormal excretion rates, resulting in negative nitrogen balance, may be associated with severe stress due to multiple trauma, head injury, sepsis, or extensive burns. Elevated values >2.5 g total fecal nitrogen/24 hours are usually found in cases of chronic progressive pancreatitis. The goal with therapy for a depleted person is a positive nitrogen balance of 4 to 6 g nitrogen/24-hours.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
Send ENTIRE STOOL COLLECTION (must contain at least 10 g of feces) frozen on dry ice in Mayo Medical Laboratories approved container.
Measurement of both urine and fecal nitrogen is necessary for the accurate determination of nitrogen balance.
Specify length of collection period and total weight of entire stool specimen.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Phinney SD: The assessment of protein nutrition in the hospitalized patient. Clin Lab Med 1981;1:767-774
2. Veldee MS: Nutritional assessment, therapy, and monitoring. In Tietz Textbook of Clinical Chemistry. Third edition. Edited by CA Burtis, ER Ashwood: Philadelphia, WB Sanders Company, 1999; pp 1385-1386
3. Konstantinides FN, Kostantinides NN, Li JC, et al: Urinary urea nitrogen: too insensitive for calculating nitrogen balance studies in surgical clinical nutrition. J Parenter Enteral Nutr 1991;15:189-193
Method Description Describes how the test is performed and provides a method-specific reference
The Rapid NIII Cube utilizes the Dumas combustion method of determining total nitrogen in feces. Homogenized fecal material (0.5 g) is added to 0.1 g 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 C. Nitrogen in the form of nitric oxide is released from the sample 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 sample.(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
Test Classification Provides information regarding the medical device classification for laboratory test kits and reagents. Tests may be classified as cleared or approved by the US Food and Drug Administration (FDA) and used per manufacturer's instructions, or as products that do not undergo full FDA review and approval, and are then labeled as an Analyte Specific Reagent (ASR), Investigation Use Only (IUO) product, or a Research Use Only (RUO) product.
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.
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.
84999 (See CPT Coding in Special Instructions)
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|
|17417||Nitrogen, Total 48/72/96 Hr, F||16141-4|