Lab Determination of Serum Creatinine. Methods and Results

Scientific Study from the year 2016 in the subject Chemistry - Analytical Chemistry, grade: 82.00, Moi University, language: English, abstract: Creatinine is considered to be a waste product of phosphocreatine and creatine. Thus, it is among the common analytes in clinical chemistry, apart from glucose. There are a number of methods used to analyze creatinine; these methods have evolved from the first reaction described by Jaffe in 1880s. Scientists, over the years, have progressed Jaffe's method through various phases. This method employed deproteinized blood and to improve its specificity, it isolated creatinine from other common substances that interfered with the process through absorption on the aluminium silicates, followed by its extraction into the alkaline picrate after decanting. Performing Jaffe's method at alkaline pH and neutral pH are among other strategies that are used to improve specificity. The only reaction at the neutral pH in this method is that of interfering substances; this result in a more accurate outcome. Using Jaffe s reaction method, when creatinine is exposed to the picric acid which is in an alkaline substance, it quantitatively produces an orange color. An experiment performed by Toora and Rajagopal (2002) indicated that after an incubation duration of approximately 15 minutes, at a normal temperature the orange color developed. Furthermore, the experiment also found out that it only requires a protein free of serum urine, one percent acid and approximately 0.75N NaOH for the orange color to develop. 1.0, 0.75 and 0.25N NaoH are the only alkaline measurements that produce the maximum orange color in PFF, standard and urine serum respectively. Moreover, the experiment also noted that the standard creatinine solution is prepared in 0.1N HCI and a PFF of serum is made by mixing the creatinine solution with a fresh tungstic acid. Thus, directly diluted sample of urine is required for measurement of creatinine.