Creatine oxidase assay is a commonly used method for creatinine test, and low creatinine oxidase assay generally means low creatinine test result. Currently, the more clinically used methods for detecting creatinine are picric acid method and enzyme method, among which serum creatinine concentration by creatine oxidase method is an important means of clinical diagnosis of diseases, especially in renal diseases, which is used for calculating creatinine clearance, estimating glomerular filtration rate, and then making judgment on the degree of renal function impairment. Low serum creatinine concentration measured by creatine oxidase method may be caused by the low creatinine level itself, which usually has no effect, and may reflect the low activity of the body, poor nutritional status and so on. It may also be due to the application of calcium hydroxybenzenesulfonate, phenolsulfonyl ethylamine, vitamin C, dopamine, dobutamine and other drugs and thus low serum creatinine concentration by creatine oxidase assay. When the serum creatinine concentration by creatine oxidase method is low, you can first clarify whether you are taking calcium hydroxybenzenesulfonate and other drugs that negatively interfere with creatinine creatinine oxidase method, or you can go to the regular hospital and apply the picric acid and other methods to measure it again, in order to avoid the inaccuracy of the measurement results affecting the judgment of the condition. If the creatinine concentration is low, it may be malnutrition, which requires timely consultation and treatment as prescribed by the doctor.