一、病因学: 近年关于肝炎方面的研究进展很快。IgM抗-HAV在急性甲型肝炎后10～12周内可检出,对诊断与鉴别诊断均有助。血清HBsAg-IgM复合物若在病程第5周仍然存在,可能就是慢性乙型肝炎的征象。关于非甲非乙肝炎的诊断目前仍主要依赖于黑猩猩接种方法协助。黑猩猩得病后肝脏活检,发现有特征性超微结构变化。在日本,非甲非乙肝炎占输血后肝炎的90％, First, the etiology: In recent years, research on hepatitis has progressed rapidly. IgM anti-HAV in 10 ~ 12 weeks after acute hepatitis A can be detected, the diagnosis and differential diagnosis are helpful. Serum HBsAg-IgM complexes that persist in the fifth week of disease may be signs of chronic hepatitis B. The diagnosis of non-A, non-B hepatitis remains largely dependent on the assistance of chimpanzees vaccination methods. After the chimpanzees liver disease biopsy, found that there are characteristic ultrastructure changes. In Japan, non-A non-B hepatitis accounts for 90% of post-transfusion hepatitis,