Algorithm for diagnosis and treatment of HAdV infections. Algorithm for diagnosis and treatment of HAdV infections. This algorithm was established based on the insights provided by studies performed at our center (69). It is important, however, that the indicated absolute threshold value of 106 virus copies/g of stool may be dependent on the specific real-time quantitative PCR (RQ-PCR) approach used in our study and may require adjustment when using other quantitative approaches. Initiation of antiviral therapy at the proposed preinvasive stage may inhibit or slow down proliferation of the virus until recovery of the immune system permits control of the infection. This approach may be instrumental in preventing life-threatening disseminated HAdV disease in individuals at high risk, while limiting the rate of overtreatment in patients after allogeneic HSCT. Screening of PB specimens is usually terminated after documentation of stable PCR negativity. However, the risk of relapse after successful treatment of adenovirus and resolution of HAdV DNAemia may be difficult to assess. Further molecular monitoring should therefore be based on the individual risk profile. In high-risk situations, continued monitoring of both stool and blood specimens may be warranted. *, high-risk parameters include T-cell depletion, GvHD (≥grade II), other, concomitant viral infections, and CD3+ counts of <300/μl PB; **, for patients who are HAdV positive in stool, with <103 virus copies/g after day 28, and do not display any high-risk features, the intervals of testing can be extended further; ***, ribavirin may be indicated only in the presence of HAdV species C; ****, <1-log reduction of viral load within ∼2 weeks of treatment. w/o, without. (Reprinted from reference 69 with permission.)‏ Thomas Lion Clin. Microbiol. Rev. 2014; doi:10.1128/CMR.00116-13