Wastewater SARS-CoV-2/COVID-19 Testing with
ddPCR Technology:
An accurate approach to absolute quantification
Droplet Digital PCR (ddPCR) technology is a wastewater
surveillance approach that offers superior sensitivity and absolute
quantification for the detection of outbreaks and specific variantsof SARS-CoV-2 in communities.
Compliant with FDA guidance for SARS-CoV-2 quantification.
CDC recommended over bulk quantification methods.
Published as dependable viral quantification method for wastewater by EPA.

COVID-19 Poses Persisting Public Health Challenges

12Novel variants ofCOVID-19 continue
to emerge andspread

3Identifying
asymptomaticindividuals remainsa challenge

Sensitivity, accuracy,
and speed of results
can be lacking

ddPCR Testing for Wastewater Surveillance
ddPCR technology uses a water-emulsion droplet system to partition nucleic acid samples
and perform PCR amplification within each droplet. It can detect SARS-CoV-2 viral RNA shedin wastewater, providing real-time surveillance of spread at the community level.
In a recent study (Gonzalez et al., 2020), fluctuations in COVID-19 wastewater measurements
predicted increases in confirmed case numbers in the area.1“We can be confident in our detection with Droplet
Digital PCR technology — we know each test will
be a true positive or negative.”

Walter Betancourt, PhD
Assistant Research Professor,
University of Arizona

Benefits of ddPCR Technology
Faster Results

ddPCR assays enable scientists to detect coronavirus 6 days before
clinical testing.2
Wastewater surveillance detects SARS-CoV-2
DAYS AFTER
INFECTION

0

Infected

12

3

4

Clinical testing detects SARS-CoV-2

5678109Contagious
SymptomaticTestingResults

DetectsMore Sensitive Results

1

infected individual in

10,000Partitioning allows for enrichment of rare targets.

Absolute Quantification

Directly count DNA molecules and eliminate standard curves.

Inhibitor Tolerance
End-point PCR uncouples quantification from amplification and efficiency.

Variant Identification

ddPCR assays can accurately discriminate and quantify multiple variants in asample using a single-well test.

Stability of Assay Design

Designed to measure genes thatare less mutated and more stable
as amplification regions.

Bio-Rad’s PREvalence ddPCR
SARS-CoV-2 Wastewater
Quantification Kit measures the Eand N2 genes in SARS-CoV-2 andincludes assays for the Murine
Coronavirus or Murine Hepatitis Virus(MHV). The test allows for all 3
targets to be detected in a single well.

Cost-efficacy

Smaller sample requirements drive down cost.

“We chose ddPCR testing for our wastewater
surveillance because it’s particularly resistant toinhibition, gives absolute quantification, and ismore sensitive than other methods.”

Carol Wilusz, PhD
Professor,
Colorado State University

The ddPCR Workflow
ddPCR testing is a 1-step process where reverse transcription and PCR are performed on
individual droplets in the same reaction mixture. This process is considered advantageous
since it can reduce RT inhibition compared to bulk solutions.4

Industries that may Benefit from ddPCR SurveillanceCollege & Universities

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References
1.Gonzalez R et al. (2020). COVID-19 surveillance in Southeastern Virginia using wastewater-based epidemiology. WaterResearch, 186 https://doi.org/10.1016/j.watres.2020.116296
2.Medema G et al. (2020). Presence of SARS-Coronavirus-2 RNA in Sewage and Correlation with Reported COVID-19
Prevalence in the Early Stage of the Epidemic in The Netherlands. Environmental Science & Technology Letters, 7(7),511-516 https://doi.org/10.1021/acs.estlett.0c00357
3.Hart O & Halden R. (2020). Computational analysis of SARS-CoV-2/COVID-19 surveillance by wastewater-based
epidemiology locally and globally: Feasibility, economy, opportunities and challenges. Science of The Total Environment, 730
https://doi.org/10.1016/j.scitotenv.2020.138875
4.Wastewater Surveillance Testing Methods. (2021). CDC.gov
https://www.cdc.gov/healthywater/surveillance/wastewater-surveillance/testing-methods.html