Comparison of auto sampling and passive sampling methods for SARS-CoV-2 detection in wastewater

Melissa Wilson, Yuanyuan Qiu, Jiaao Yu, Bonita E. Lee, David T. McCarthy, Xiaoli Pang

Research output: Contribution to journalArticleResearchpeer-review

16 Citations (Scopus)


Wastewater-based surveillance is emerging as an important tool for the COVID-19 pan-demic trending. Current methods of wastewater collection, such as grab and auto-composite sam-pling, have drawbacks that impede effective surveillance, especially from small catchments with limited accessibility. Passive samplers, which are more cost-effective and require fewer resources to process, are promising candidates for monitoring wastewater for SARS-CoV-2. Here, we compared traditional auto sampling with passive sampling for SARS-CoV-2 detection in wastewater. A torpedo-style 3D-printed passive sampler device containing both cotton swabs and electronegative filter membranes was used. Between April and June 2021, fifteen passive samplers were placed at a local hospital’s wastewater outflow alongside an autosampler. Reverse transcription and quantitative polymerase chain reaction (RT-qPCR) was used to detect SARS-CoV-2 in the samples after processing and RNA extraction. The swab and membrane of the passive sampler showed similar detection rates and cycle threshold (Ct) values for SARS-CoV-2 RNA for the N1 and N2 gene targets. The passive method performed as well as the grab/auto sampling, with no significant differences between N1 and N2 Ct values. There were discrepant results on two days with negative grab/auto samples and positive passive samples, which might be related to the longer duration of passive sampling in the study. Overall, the passive sampler was rapid, reliable, and cost-effective, and could be used as an alternative sampling method for the detection of SARS-CoV-2 in wastewater.

Original languageEnglish
Article number359
Number of pages9
Issue number3
Publication statusPublished - 16 Mar 2022


  • autosampler
  • passive sampler
  • RT-qPCR
  • SARS-CoV-2
  • wastewater

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