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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