Test Code LAB10185 Urea Nitrogen - 24 Hour Urine
Department
CHEMISTRY
Collection Requirements
24 hour urine.
Do not add preservatives to the collection container.
Keep the container on ice or refrigerated during collection.
Empty bladder and discard, note time, collect all urine for 24 hours placing last void in container.
Note total urine volume.
Primary Collection Container
24 HR Urine container
Transport
Refrigerated
Preferred Transport Temperature
Refrigerated
Processing
Keep specimen refrigerated until processing.
Measure total volume.
Aliquot, centrifuge and refrigerate.
Note total volume on the label.
Stability
Ambient: 8 hours
Refrigerated: 1 week
Frozen: Unacceptable
Minimum Testing Volume
0.1 mL
Reference Range
12-20 gm/24hr
Methodology
Urease specifically hydrolyzes urea to form ammonia and carbon dioxide. The ammonia is used by the enzyme glutamate dehydrogenase (GLDH) to reductively aminate a-ketoglutarate (a-KG), with simultaneous oxidation of reduced nicotinamide-adenine dinucleotide (NADH). The change in absorbance at 340 nm due to the disappearance of NADH is directly proportional to the urea nitrogen concentration in the sample and is measured using a bichromatic (340, 383 nm) rate technique. Siemens Dimension Vista.
Performed
Sunday – Saturday
Reported
As completed
CPT Codes
84540