The present invention is drawn to a new diagnosis method for detecting the extent of hepatic steatosis in a patient, in particular in a patient who suffers from a disease involving hepatic steatosis, or who already had a positive diagnosis test of liver fibrosis and/or presence of liver necroinflammatory lesions, by using the serum concentration of easily detectable biological markers. The invention is also drawn to diagnosis kits for the implementation of the method.