We’re currently testing for SARS-CoV-2 which includes variant classification, and we will be adding additional human pathogens, including Norovirus, Hepatitis A, Flu A/B and RSV later this year.
By analyzing wastewater for both genetic material from infectious pathogens which are shed in human feces and urine, and crAssphage, a bacteriophage commonly found in stool, we use the ratio of these two indicators to assess the amount of a specific pathogen in relation to a baseline reading of crAssphage, which is used as a benchmark reading of human population.
Test results of this come as a PCR machine readout, which is then interpreted by our technical team to determine if the sampling location is Non-detect, detected, or quantifiable for the pathogen of interest (Quantifiable= very high COVID/crAssphage levels). When samples are collected and analyzed on a consistent routine a baseline is established and the change indicates a steady state, or an increase or decrease in infection. These results are most valuable when your institution has an action plan on how to respond to a positive hit.
- The wastewater sample collection is conducted by the wastewater treatment plant’s field personnel for municipal wastewater testing. For private institutions, sampling can be contracted through an environmental field services company that employs certified field technicians to collect the sample.
- Quadrant does not collect the sample, our lab performs the analysis of the sample.
- Here is a link to the full Sampling and Transport Protocol that can help to answer any questions regarding sampling.
- We work with a number of contract samplers, if we work with one in your region and you need assistance, we’ll refer you to them or help in identifying support.
The $300 fee does not include shipping, and samples need to be overnighted using gel ice packs, however, most local customers drive samples to Syracuse to ensure sample integrity is the highest possible. (SARS-CoV-2 RNA degrades, especially in higher temperatures.)
The samples should be received within 24 hours of collection, if you are not delivering samples in person, then they need to be shipped overnight, preferably on gel ice packs. Dry ice should not be used.
Our school supports a live-on population of roughly 75 people, with an additional day population of about 40 people. In your expertise or opinion, can Quadrant Biosciences provide reliable results for such a (relatively) small group?
Yes, as we are looking at a ratio of people to SARS-CoV-2 RNA detected in the wastewater.
Samples collected from a composite sampler are preferred but multiple grab samples will be accepted.
If samples are received at the Quadrant Viral Testing Laboratory before 3pm, an analysis report will be sent out within two business days. If after 3pm, you’ll receive an analysis in 3 business days.
Do the collection bottles need to be as specific as the ones linked to in the files sent? As long as we have a new 250 ml plastic bottle with a tightened top, will that suffice?
Any clean, commonly provided bottle should work.
Do we need to provide a sheet that outlines when we project samples will arrive and how many will we have each week?
Once your contract has been accepted, you will set up a drop-off schedule with our Supply Chain Associate, Kyle O’Brien.
It is crucial to label the bottle with location and time the sample was collected; full instructions on labeling can be found in the Sampling and Transport Protocol, this protocol will also outline our Chain of Custody documentation.
Results are emailed within two business days of receiving the samples if received before 3pm.
The lab is currently not open on weekends, so samples incoming Thursday will be reported by EOB Monday, with Friday's results getting reported by EOB Tuesday. We know this is not ideal, and are currently in discussions on opening the lab on weekends. We are starting to see sample volumes that justify this, and I would assume that operation on the weekend will be starting in the near future.
Normalization is done by comparing the number of SARS-CoV-2 RNA copies to the number of crAssphage DNA and RNA copies.
We account for dilution by standardizing the number of SARS-CoV-2 RNA copies to the number of crAssphage DNA and RNA copies when we interpret the results. crAssphage is a gut bacteriophage carried by more than half the American population whose shedding rate is well characterized. We have seen a near-perfect correlation (r = 0.99) between crAssphage DNA and the sewer shed population times sewer flow. CrAssphage allows us to go upwards in the sewer system where flow data is sparse and obtain valid estimates of SARS2 transmission trends.
Our method of processing SARS-CoV-2 is below 1 per 20,000 individuals. From May - August we observed among non-detections of SARS-CoV-2 RNA the COVID-19 incidence 5-9 days later had an average of 1 case per 10,000 population.
Can you explain a bit more (or provide an example) about how results are reported? For example you state that the result is either detect, non-detect or quantifiable if very high COVID/crAssphage levels, but how do you determine “high levels”?
Results are first categorized into non-detected, detected, or quantifiable. We see clear differentiation between these categories in terms of COVID-19 cases within the sewer shed. These categories allow for understanding in areas of low transmission. Once transmission has increased, quantifiable results easily establish trends in SARS2 transmission.
- This is a public policy decision. By continual sampling (2-3x per week for example) a baseline is created.
- From the baseline, you’ll be able to understand if an infection is starting or decreasing. With this information you’ll be much better informed of when to start a control action and if the action is controlling the infection.
The number of coronavirus RNA copies we’ve measured ranges from 5 (limit of quantification) up to 642.
Is there a correlation between the case level and that range that would help me explain the results?
Sample: An institution's recent result of 108 is on the high end, and increasing. I would be concerned by the numbers. With once per week sampling it’s difficult to determine if this is a trend or just a wild sampling point though.