Biosystems Urea Reagent
- Reagent for the measurement of urea concentration in human serum, plasma or urine.
- The obtained values are useful as an aid in the diagnosis and treatment of chronic renal failure, and to evaluate the function of renal glomerulus.
- This reagent is for use in the BioSystems BA analyzers or in other analyzer with similar performance characteristics.
- Urea is synthesized in the liver as a by-product of the deamination of amino acids. Its elimination in the urine represents the major route for nitrogen excretion.
- Elevated urea concentration in plasma is found as a result of a high-protein diet, increased protein catabolism, after a gastrointestinal hemorrhage, mild dehydration, shock and heart failure
or treatment with glucocorticoids (pre-renal uremia)1,2
- Post-renal uremia is caused by conditions that obstruct urine outflow: nephrolithiasis, tumor or prostatic hypertrophy.
- The usefulness of urea as an indicator of renal function is limited by the variability of its plasma concentration as a result of nonrenal factors1,2
- Clinical diagnosis should not be made on the findings of a single test result, but should integrate both clinical and laboratory data.
PRINCIPLE OF THE METHOD
- Urea in the sample consumes, by means of the coupled reactions described below, NADH that can be measured by spectrophotometry3,4
- A. Reagent: Tris 100 mmol/L, 2-oxoglutarate 5.6 mmol/L, urease 140 U/mL, glutamate dehydrogenase 140 U/mL, ethyleneglicol 220 g/L, sodium azide 0.95, pH 8.0.
- B. Reagent: NADH 1.5 mmol/L, sodium azide 9.5 g/L.
- WARNING: H302: Harmful if swallowed. EUH031: Contact with acids liberates toxic gas. P301+P312: IF SWALLOWED: Call a POISON CENTER or doctor/physician if you feel unwell.
- P330: Rinse mouth. For further warnings and precautions, see the product safety data sheet (SDS).
STORAGE AND STABILITY
- Store at 2-8 ºC.
- Components are stable once opened until the expiry date marked in the label if they are stored well closed and care is taken to prevent contamination during their use.
- On board stability: Reagents open and kept in the refrigerated compartment of the analyzer are stable 30 days.
- Indications of deterioration: Absorbance of the blank below the limit indicated in “Test Parameters”.
ADDITIONAL MATERIALS REQUIRED (NOT PROVIDED)
- Biochemistry Calibrator (BioSystems cod. 18011) or Biochemistry Calibrator Human (BioSystemscod. 18044).
- Reagents are provided ready to use.
- Serum, plasma or urine collected by standard procedures.
- Urea in serum or plasma is stable for 7 days at 2-8ºC. Heparin is recommended as anticoagulant5
- Urea in urine is stable for 2 days at room temperature if microbial growth is prevented5
- A reagent blank should be done every day and a calibration at least every 30 days, after reagent lot change or as required by quality control procedures.
- It is recommended to use the Biochemistry Control Serum level I (cod. 18005, cod. 18009 and
cod. 18042) and II (cod. 18007, cod. 18010 and 18043) and the
- Biochemistry Control Urine (cod.18054 and cod. 18066) to verify the accuracy of the measurement procedure. Each laboratory should establish its own internal
- Quality Control scheme and procedures forcorrective action if control results are not within the acceptable limits.