U4 LAB: URIC ACID Flashcards
Byproduct of purine nucleic acid catabolism
Uric Acid
Main form in plasma
Monosodium urate
Clinical applications
- confirm diagnosis and monitor treatment of gout
- prevent uric acid nephropathy during chemotherapeutic treatment
- assess inherited disorders of purine metabolism
- detect kidney dysfunction
- assist in diagnosis of renal calculi
Non specific method and requires protein removal
Caraway method
Caraway Method
based on reduction of ________ in alkaline solution to tungsten blue
phosphotungstic acid
More specific and more commonly used
Enzymatic (Uricase) method
Uricase is used to catalyze ______ of uric acid to?
oxidation, allantoin
Measures the hydrogen peroxide produced as uric acid
Coupled enzymatic reaction
Coupled enzymatic reaction measures?
hydrogen peroxide
Coupled enzymatic reaction
Color produced is?
directly proportional to uric acid
Coupled enzymatic reaction
Sources of error
reducing agents (bilirubin and ascorbic acid)
This method measures differential absorbance before and after incubation with uricase.
Spectrophotometric assay
Spectrophotometric assay
Absorbance is measured at what wavelength?
293 nm
Spectrophotometric assay
What is directly proportional to uric acid?
difference
Spectrophotometric assay
Sources of error
protein, hemoglobin, xanthine