U4 LAB: BUN Flashcards
Nitrogen-containing compounds measured after removal of proteins in specimen
Non-Protein Nitrogen
NPNs are measured by converting nitrogen to?
ammonia
Subsequent reaction with what reagent forms a yellow product?
Nessler’s reagent (K2[HGI4])
Specimen for NPNs
Urine and Plasma
Urea is also known as?
Carbamide
Highest concentration in blood, major excretory product of protein metabolism
Urea
Chemical Formula of Urea
CO(NH2)2
Clinical Applications
- Evaluation of renal function
- Assess hydration status
- Determination of nitrogen balance
- Aid in diagnosis of renal disease
- Verify adequacy of dialysis
More appropriate term for quantification of Urea
Blood Urea Nitrogen (BUN)
Conversion factor
BUN to Urea
2.14
Conversion factor
BUN Conventional to SI
0.357
Most frequently used method
Enzymatic (Urease) Method
This enzyme catalyze hydrolysis of urea and the liberated ammonium ion is quantified.
Urease
Most common assay, best as kinetic measurement
Glutamate dehydrogenase (GLDH)-coupled enzymatic reaction
GLDH
Measures rate of disappearance of reduced ______ at what wavelength?
Nicotinamide adenine dinucloetide, 340 nm
This is used in automated systems, multilayer film reagents and dry reagent strips
Indicator dye
Indicator dye measures color change due to?
change in pH
This is a specific and rapid test which uses an electrode
Conductometric
Conductometric
The electrode is used to measure?
rate of increase in conductivity procued by ammonium ions
Reference method
Isotope Dilution Mass Spectrometry (IDMS)
IDMS
Used for quantification
isotopically-labeled compound
IDMS
Detects what following ionization?
characteristic fragments
Samples for Urea
Serum, Plasma, Urine
Urine is stable up to 4 days if stored in?
2-8C temp
