Early detection of Aspergillus infection after allogeneic stem cell transplantation by polymerase chain reaction screening

Invasive aspergillosis (IA) has become a major cause of mortality in patien ts after allogeneic stem cell transplantation. To assess the potential of p rospective polymerase chain reaction (PCR) screening for early diagnosis of IA, 84 recipients of an allogeneic stem cell transplant were analyzed with the investigators blinded to clinical and microbiologic data. Of 1193 bloo d samples analyzed, 169 (14.2%) were positive by PCR, En patients with newl y diagnosed IA (n = 7), PCR positivity preceded the first clinical signs by a median of 2 days (range, 1-23 days) and preceded clinical diagnosis of I A by a median of 9 days (range, 2-34 days). Pretransplantation IA (relative risk [RR], 2.37), acute graft-versus-host disease (RR, 2.75), and corticos teroid treatment (RR, 6.5) were associated with PCR positivity. The PCR ass ay revealed a sensitivity of 100% (95% confidence interval [CI], 48%-100%) and a specificity of 65% (95% CI, 53%-75%), None of the PCR-negative patien ts developed IA during the study period. Thus, Prospective PCR screening al lows for identification of patients at high risk for subsequent onset of IA .