ObjectiveTo systematically review transfusion of red blood cells with different duration for patients' prognosis so as to provide evidence for the reasonable blood use in clinic. MethodsDatabases including The Cochrane Library (Issue 3, 2013), PubMed, Ovid, EMbase, WanFang Data and CNKI were electrically searched to collect studies published from 2002 to 2013, and relevant periodicals and references of the included studies were also manually retrieved. According to the inclusion and exclusion criteria, related studies were screened, data were extracted, and the quality of included studies was evaluated by two reviewers independently. Then meta-analysis was conducted using RevMan 5.0 software. ResultsA total of 10 studies (including 4 case-control studies and 6 cohort studies) were included, involving 15 187 patients. The results of meta-analysis revealed that, transfusion of fresh red cells (≤10-18 days) was superior to that of old ones ( > 14-28 days) in decreasing the short-term mortality (OR=0.69, 95%CI 0.58 to 0.82, P < 0.000 1) and the incidence of hospital infection (OR=0.67, 95%CI 0.55 to 0.81, P < 0.000 1), and in decreasing the incidences of post-operation kidney failure (OR=0.52 95%CI 0.37 to 0.73, P=0.000 2) and prolonged ventilatory support ( > 72 h) (OR=0.54 95%CI 0.45 to 0.66, P < 0.000 01) for patients with cardiac surgery, all with significant differences. ConclusionTransfusion of fresh red cells (≤10-18 days) is superior to that of old ones ( > 14-28 days) in decreasing the short-term mortality and the incidence of hospital infection, and in decreasing the incidences of post-operation kidney failure and prolonged ventilatory support ( > 72 h) for patients with cardiac surgery, which improve prognosis. Due to the limited quality and quantity of the included studies, the aforementioned conclusion needs to be verified by conducting more high quality studies.