Soluble microbial products, consisting of protein, carbohydrate and humics, are generally considered as the main membrane foulants during the performance of membrane bioreactors. Nitrate and nitrite have been proved to affect the determination of carbohydrate when anthrone-sulfuric acid photometric method is used. In this study, three chemical analytical methods based on photometric assay, including the standard curve method, conventional standard addition method and H-point standard addition method, were assessed for the quantification of carbohydrate in order to reduce the interference. Three methods were carried out for both artificial and real wastewater sample analysis. The results indicated a significant amount of matrix interference, which could be eliminated through the use of H-point standard addition. This study proposed the H-point standard addition method as a more accurate and convenient option for carbohydrate determination.