For the quantitative measurement of rat creatinine assay kit in serum and urine with a range of 0.15-141 mg/dL and an assay time of < 30min. The kits are easy-to-use, require < 10 μL of sample, and have low interference. Designed for rat serum and urine samples, the kits use an enzymatic method that provides superior results over the traditional Jaffe method which has been shown to significantly overestimate creatinine levels in rats.