Cytokeratin 18 (CK 18) is a simple non invasive test that accurately distinguishes (NASH) nonalchoholic steatohepatitis from (NAFLD) non alcoholic fatty liver disease. Cytokeratins are proteins of intermediate filaments that contain keratin found in the intracytoplasmic cytoskeleton of epithelial tissue. Liver biopsy being the best standard for diagnosing NASH has its share of limitations. Therefore it is urgent and important to conduct a non invasive test that can accurately distinguish NASH from simple steatosis. NAFLD has become a very common but important problem due to its prevalence and progression to severe liver disease. It refers to excessive amount of lipid in the liver. In some individuals it progresses to NASH.