fig1

Figure 1. Decision tree for selecting between RT-PCR and ddPCR platforms in wastewater surveillance programs. Green boxes indicate scenarios where RT-PCR is sufficient or preferred, blue boxes indicate where ddPCR is preferred or strongly recommended, and yellow boxes indicate either platform is viable. Key decision points include data output requirements, target abundance expectations, PCR inhibition prevalence, sample throughput needs, inter-laboratory data harmonization requirements, budget constraints, and anticipated participation in the NWSS. RT-PCR: Reverse transcription polymerase chain reaction; ddPCR: droplet digital polymerase chain reaction; NWSS: National Wastewater Surveillance System.