Diazyme Receives 510(K) FDA Clearance for Potassium Enzymatic Assay Kit

SAN DIEGO, CA - October 29, 2004 - Diazyme Laboratories, a company that applies its proprietary Substrate Trapping-Enzyme Technology?(STE) platform to develop low cost and high quality diagnostic products for clinical and research uses, announced today that the U.S. Food and Drug Administration (FDA) has granted Diazyme 510(K) clearance to market their Potassium Enzymatic Assay Kit for the quantitative in vitro determination of potassium in serum samples.

Potassium is determined spectrophotometrically through a kinetic coupling assay system using potassium dependent urea amidolyase (UAL). NADH generated in a coupling enzymatic reaction reduces a water soluble colorless tetrazolium salt, WST-1, in the presence of an electron mediator, 1-methoxy-5-methyl-phenazinium methyl sulfate (PMS), to form a water soluble formazan dye, which has a maximum absorbance at 438 nm. The corresponding increase of optical density at 438 nm is proportional to the potassium concentration in the serum.

Key Assay Characteristics: Diazyme's Potassium Enzymatic assay is a two reagent (R1 and R2) based assay system. The results are obtained in 10 minutes by measuring absorbance at 450nm. No off line pretreatment is needed. The assay has excellent accuracy and precision with a wide measuring range (2 to 8 mmole/L).

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