Patent ID: 11921124
Assignee: SIEMENS HEALTHCARE DIAGNOSTICS INC.
Field: Measurement (Instruments)
Classification: CPC G  A  C | IPC A  C  G

Claim 10:
11. A method of stabilizing the pH of an aqueous diagnostic quality control or calibration reagent containing urea and at least one buffer, wherein an original urea concentration of the aqueous diagnostic quality control or calibration reagent is in a range of from about 0.1 mM to about 150 mM, the method comprising the step of:
disposing asparagine into the aqueous diagnostic quality control or calibration reagent such that a ratio of urea to asparagine is in a range of from about 0.1:1 to about 100:1,
wherein an original pH of the aqueous quality control or calibration reagent is in a range of from about 6 to about 8, and whereby the pH of the aqueous quality control or calibration reagent varies by +/−1.0 or less of the original pH following storage of the composition, and further wherein formation of ammonia in the aqueous diagnostic quality control or calibration reagent is substantially reduced by at least 5% following storage of the composition when compared to a composition prepared in the absence of asparagine and following storage thereof; and
wherein the aqueous diagnostic quality control or calibration reagent is brought into direct contact with a diagnostic sensor for calibration or quality control of the diagnostic sensor.