Technical Summary: Urea Analysis (Bulletin ref. TB098610F)
 

A fast enzymatic analysis for blood urea using urease and GLDH.
 

Name:
Code:
Size:

Urea
GMRD-086
2 x 40 tests (140 analyser cycles)
 

Instruments:
 

All GM7/UM2 Series analysers
 

Principle:

i) Ammonia liberated from urea by urease is converted into L-glutamate by glutamate dehydrogenase (GLDH) in the presence of excess NADH in a brief pre-reaction:
 

ii) Under the conditions of the assay, the rate of oxidation of excess NADH by peroxidase (POD) is inversely proportional to urea concentration:

Samples:
Sample volume:
Linearity:
Precision:

Whole blood, plasma, serum, urine
10 µl
30 mmol/L (180 mg/dl) (84 mg/dl BUN)
Typical within-run 0.16 mmol/L (C.V. = 1.1 % @ 14.0 mmol/L)
 

Accuracy:

i) Plasma vs Beckman urease conductimetric procedure:
y (Analox) = 0.993x + 0.15 mmol/L, r = 0.998, n = 100
ii) Plasma vs Urease/Berthelot method:
y (Analox) = 1.01x - 0.108 mmol/L, r = 0.999, n = 93
 

Reagent Stability:

Shelf-life 12 months unopened when stored at 0 - 5°C. Reconstituted urease/NADH/GLDH, 7 - 10 days (2 vials) if stored at 0 - 5°C.