For quantitative determination of creatinine and evaluation of drug effects on its metabolism.

• Fast and sensitive
• Linear detection range: 4.8 to 500 µM or 0.054 to 5.7 mg/dl (colorimetric assay) and 0.25 to 100 µM or 0.0028 to 1.14 mg/dl (fluorimetric assay) for a 60 min reaction
• It is 3- and 53-fold more sensitive than the traditional Jaffe method (e.g. DICT-500), especially useful for small samples or where high sensitivity is required
• Convenient
• The procedure involves adding a single working reagent and reading after 60 minutes
• Room temperature assay
• No 37 °C heater is needed
• High-throughput
• Homogeneous 'mix-incubate-measure' type assay
• Can be readily automated to process thousands of samples per day

CREATININE is synthesized in the body from creatine, which is produced during muscle contractions from creatine phosphate. In the blood, creatinine is removed by filtration through the glomeruli of the kidney and is secreted into urine. In healthy individuals, creatinine secretion is independent of diet and is fairly constant. The creatinine clearance test has become one of the most sensitive tests for measuring glomerular filtration rate.

In kidney disease, creatinine levels in the blood are elevated, whereas the creatinine clearance rate and hence the urine levels are diminished. Creatinine testing is most widely used to assess kidney function. BioAssay Systems’ enzyme-based creatinine assay uses a reaction sequence that excludes endogenous ammonia to convert a dye into a colored and fluorescent form. The absorbance at 570 nm or fluorescence intensity at λex/em = 530/585 nm is directly proportional to the creatinine concentration in the sample.