Creatine Assay for Use on Bench Top Chemistry Analyzer: Quick Analysis of Creatine in Human Serum Smaples

Creatine (Cr) was initially discovered in the 1830s by a Frenchman named Chevreul. In subsequent years, it was discovered that creatine was utilized by the musculatory system, which fueled research on its overall use as a metabolite in the human body. Investigation into the role of this chemical in the human body led to its current use as a sports supplement and potential treatment option for individuals with musculatory disorders such as Parkinson’s and Huntington’s. With creatine’s increased use as a sports supplement there is also a strong interest in its long term effects, as well as its potential as a treatment option. There is need for further investigation as well as a means for dosage determination, and a method that will allow for accurate concentration determination. The current methods used to determine creatine concentration are time consuming and complicated analytical methods such as high pressure liquid chromatography (HPLC) and gas chromatography-mass spectroscopy (GS-MS). A single reagent enzymatic assay (Cr assay) that can be used on any bench top chemistry analyzer for accurate and precise measurement of Cr in human serum and aqueous samples was developed and is summarized here. The assay can measure samples in 10 minutes, is linear from 0-15mg/dL of Cr, the reagent has a shelf life of 45 days refrigerated. The Cr assay is within 98% accuracy, run to run CV from 1.6-5.3% for clinical samples and a sample-to-sample CV of less than 0.5%. This assay can easily be adapted for any bench top chemistry analyzer that has the capability of a programmable channel, and can read clinical samples with accuracy, precision and reproducibility.