Urea is the final result of the metabolism of proteins; it is formed in the liver
from their destruction.
It can appear the urea elevated in blood (uremia) in: diets with excess of
proteins, renal diseases, heart failure, gastrointestinal hemorrhage,
dehydration or renal obstruction1,4,5.
Clinical diagnosis should not be made on a single test result; it should
integrate clinical and other laboratory data.
STORAGE AND STABILITY
All the components of the kit are stable until the expiration date on the label
when stored tightly closed at 2-8ºC, protected from light and contaminations
prevented during their use.
Do not use reagents over the expiration date.
Signs of reagent deterioration:
- Presence of particles and turbidity.
- Blank absorbance (A) at 510 nm 0,20.
ADDITIONAL EQUIPMENT
- Spectrophotometer or colorimeter measuring at 510 nm.
- Matched cuvettes 1,0 cm light path.
- General laboratory equipment(Note 2)
SAMPLES1
- Serum or heparinized plasma1
: Do not use ammonium salts or fluoride as
anticoagulants.
- Urine1
: Dilute sample 1/50 in distilled water. Mix. Multiply the results by 50
(dilution factor). Preserve urine samples at pH 4.
NOTES
1. UREA CAL: Proceed carefully with this product because due its nature it can
get contaminated easily.
2. Glassware and distilled water must be free of ammonia and ammonium
salts1
.
3. Calibration with the aqueous standard may cause a systematic error in
automatic procedures. In these cases, it is recommended to use a serum
Calibrator.
4. Use clean disposable pipette tips for its dispensation.
BIBLIOGRAPHY
1. Kaplan A. Urea. Kaplan A et al. Clin Chem The C.V. Mosby Co. St Louis.
Toronto. Princeton 1984; 1257-1260 and 437 and 418.
2. Young DS. Effects of drugs on Clinical Lab. Tests, 4th ed AACC Press, 1995.
3. Young DS. Effects of disease on Clinical Lab. Tests, 4th ed AACC 2001.
4. Burtis A et al. Tietz Textbook of Clinical Chemistry, 3rd ed AACC 1999.
5. Tietz N W et al. Clinical Guide to Laboratory Tests, 3rd ed AACC 1995.
