CPT Code(s):
Collection Procedure:
Specimen Requirements:
- Serum, gel
- Plasma, gel
Sample Volume: 0.5 mL serum
- Refrigerated: 7 days
- Frozen: 1 year
Use:
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.
Reported:
Within 24 hours