urea in body fluid

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Principle

The Kodak Ektachem Clinical Chemistry Slide (BUN/UREA) is a dry, multilayered analytical element coated on a clear polyester support.

A 10 uL drop of patient sample is deposited on the slide & is evenly distributed by the spreading layer. Water & non- proteinaceous components then travel to the underlying reagent layer where the urease reaction generates ammonia. The ammonia then diffuses through the semipermeable membrane to react with an ammonia indicator.

The semipermeable membrane allows only ammonia to pass through to the color-forming layer where it reacts with the indicator.

After a fixed incubation period, the reflection density of the dye is measured spectrophotometrically through the polyester support using the white background of the spreading layer as a diffuse reflector

                 Urease
H2NCONH2 + H2O -----------> 2NH3 + CO2
NH3 + Ammonia Indicator ----------> Dye

Specimen

  • specimens are collected in a red top vacutainer & should be separated immediately from the cells after collection
  • minimum sample size 0.5 milliliter: with an optimum size of 1.0 mL or larger

More general terms

More specific terms

Additional terms

References

  1. Urea Nitrogen, Body Fluid Laboratory Test Directory ARUP: http://www.aruplab.com/guides/ug/tests/0020183.jsp