Laboratory findings in patients with avian-origin influenza A (H7N9) virus infections

Reports describing the laboratory findings associated with human H7N9 infections are limited. In this study, the laboratory findings of 39 patients with confirmed H7N9 infection were analyzed retrospectively. Patients were enrolled following admission to The First Affiliated Hospital, College of Medicine, Zhejiang University, the primary hospital for the treatment of patients with H7N9 infections in Zhejiang province in China between March and April in 2013. Hematological abnormalities included leukopenia, lymphopenia, thrombocytopenia with prolonged prothrombin time (PT) and activated partial thromboplastin time (APTT) as well as elevation of D-dimer levels. Biochemical abnormalities included elevated serum lactate dehydrogenase (LDH), aspartate aminotransferase (AST), creatine kinase (CK), alanine aminotransferase (ALT) activities, and increased C-reactive protein (CRP) concentration, as well as hyponatremia, hypokalemia, hypocalcemia, hypoproteinemia, and hypoalbuminemia. Arterial blood gas analysis revealed reduced arterial oxygen (PaO₂) and carbon dioxide pressures (PaCO₂). The data obtained in this study indicate that such abnormal laboratory features exhibited during the early stage of infection are common but not pathognomonic for the novel avian-origin influenza A strain H7N9; therefore, these features do not to allow the definitive differentiation of H7N9 infection from those of other viruses.