Non-protein Nitrogen Compounds

Urea, Amino acids, Uris acid, creatinine, creatine, ammonia.

Spectrophotometrically by converting nitrogen to ammonia, with the subsequent reaction being Nessler’s reagent (producing a yellow color)

Catabolism of proteins and nucleic acids

Protein metabolism

In the liver and most is excreted in the urine as a waste product. While some of it is reabsorbed depending on the state of hydration and the urine flow rate.

In plasma or serum: 6-20 mg/dl In urine, 24 hours: 12-20 g/d

Renal function, Nitrogen balance, hydration status, Adequacy of dialysis, and aid in diagnosis of renal disease.

The most frequently used method

Is the most common quantitation, it couples the urease reaction with glutamate dehydrogenase

340 nm

Proportional to the amount of BUN in the sample

An ammonium ion from urease reaction is measured by color change associated with a pH indicator (Blue indophenol)

Urea reacting with diacetylmorphine monoxime under strong acidic conditions and heat.

It condenses to produce a red color and directly measures urea content.

Is specific and rapid, and measures there rate of increase in conductivity when ammonium ions are being produced from urea.

Includes an isotope dilution mass spectrometry

The use of plasma, serum, or urine. Sodium citrate and. Sodium fluoride tubes would not be recommended due to their inhibitory effects on urease. A non-hemolyzed sample.

Is when there is an elevated concentration of nitrogen compounds (urea) being retained in the blood

Is when there is a very high plasma urea concentration accompanied by renal failure. Could include electrolyte and water imbalance and could be fatal if not treated with dialysis.

Is when there is a reduced renal blood flow, resulting in less urea filtered. Could result in Congestive heart failure, hemorrhage and dehydration.

Is when there is decreased renal function, which will then in turn increase plasma urea concentration. Which could result in kidney disease, glomerular nephritis, renal failure.

is when there is an obstruction of urine flow within the urinary tract below the kidneys causing waste build-up in the kidneys. Ie: kidney stones

The breakdown of purine nucleic acids, which most is reabsorbed in the proximal tubules and reused.

Insoluble in the plasma, and can be deposited into tissue and joints at high concentrations causing inflammation. Which could precipitate as urate crystals if levels are elevated above 6.8 mg/dl.