Creatinine, Random Urine

Methodology: 
This creatinine procedure is a kinetic modification of the Jaffe procedure, in which creatinine reacts with picric acid at alkaline pH to form a yellow-orange complex. However, this reaction is not completely specific for creatinine, since other reducing substances, such as glucose, pyruvate, ascorbic acid, and acetoacetates, will react with picrate to form a similar color. Fabiny and Ertingshausen found that alkaline creatinine picrate reaches maximum color development at a different rate than pseudo-creatinine material. Cook utilized different reaction rates of alkaline picrate positive substances to obtain greater specificity with the Jaffe reaction. The rate of change in absorbance at 520/800nm is proportional to the creatinine concentration in the sample.
Performed: 
Monday - Friday
Reported: 
Within 3 days
Specimen Requirements: 
Type: Urine, random

Container/Tube: Plastic urine container with no preservative

Sample Volume: 1 mL

Storage: Refrigerate specimens.

Specimen Retention Time: 5 days
Reference Values: 
No reference range established
CPT Code (s): 
82570
Notes: 

UFHPL Test #: 20142

UFHPL Epic order code: LAB384

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