(i) There are significant differences with respect to clinical, biochemical, immunological and virological aspects between ASL-HB and CHB-AF. (ii) Of several diagnostic combinations, IgM anti-HBc jointing HBV-DNA is most effective and most practicable in distinguishing ASL-HB from CHB-AF. (iii) A low HBeAg level is more useful than negative HBeAg in differential diagnosis between ASL-HB and CHB-AF. (iv) In those patients with a high level of IgM anti-HBc, serum AFP level >10x upper reference limit could rule out a probability of ASL-HB.