Why does my report have a “not-detected” result when there are reported cases in my area (or the virus has been detected before)?
A result of “non-detect” means the level of SARS-CoV-2 virus genetic material in the influent sample was below our limit of detection. There can be a number of reasons for this. For example, if the number of new infections in your community is small, the virus concentration in your wastewater may hover around our limit of detection.
The location of reported cases can also be a factor. If individuals who have been infected with COVID-19 do not reside in an area connected to your catchment area, then they also will not be represented in the wastewater sample.
Lastly, if the composite sampler is collecting sewage once per hour (vs. every few minutes), fragments of the virus may have evaded the sampling process.
Why is my effective concentration so different from the raw concentration? Should I be concerned?
There is no need to worry if your effective concentration is different from the raw concentration. In fact, you should expect that raw and effective concentrations differ, because the effective concentration accounts for both sample dilution and for changes or differences in lab protocols.
For example, if your samples tend to be more dilute than the average sample in our dataset, you will see consistently higher effective concentration values than your raw concentration. That is because the dilution in your samples will lead to lower PMMV levels than average, and so your sample concentrations will be corrected upwards in the normalization process.
Does your testing detect the new COVID-19 strains?
Biobot's effective concentrations will indiscriminately include all known SARS-CoV-2 variants. A variant is characterized by one or more signature changes (mutations) to the virus's genetic code (for example, B.1.1.7 has 17 mutations). Similar to standard clinical Covid-19 testing, our testing detects the SARS-CoV-2 virus by targeting the N1 & N2 regions of the genetic code (as designed by the CDC). These two regions are unchanged in the known SARS-CoV-2 variants. Therefore our testing will detect the virus variants (and original variant) all the same.
If your organization has opted in to the Biobot Network data visualization, you will be able to see your variant percentage breakdown on our website: biobot.io/data.
For more information on your reports, see https://biobot.io/covid19-report-notes/