How to Interpret Wastewater Data – Biobot Analytics

Focus on Trends

When interpreting wastewater data, we advise you to focus on trends, not individual data points in isolation.
We adjust the axes to the maximum data point on your graph.
- So, focus less on whether the clinical data and wastewater data lines intersect, for example, and more on how their trends are (or are not) tracking with each other.
- Additionally, what qualifies as a "high" or "low" concentration can depend on your locality, catchment population, and previous data.
  - Contact support@biobot.io if you have specific questions about your particular data.

Doubling or halving between only two samples is not abnormal
- 50k ➡️ 100k does not necessarily mean disease activity has doubled.
  - When the change is 2x or less, wait for the next sample to look for trends
But, more major % changes are more significant…
- 100k ➡️ 400k (4x increase) is more meaningful than 1 million ➡️ 2 million (2x increase)
…especially at higher concentrations (and especially for larger sewersheds)
- 500k ➡️ 2 million (4x increase) is more meaningful than 10k ➡️ 40k (4x increase), as it suggests that more people in total are infected.
  - When concentrations are low, just a small cluster of disease activity may lead to a significant percentage-change

One data point can reliably indicate disease presence, but avoid over-interpreting individual data points. Focus more on trends.
Any individual sample is subject to multiple sources of variation:
- Actual variation in disease activity
- Lab process variability (minimized by our lab’s rigorous QC protocols)
- Fluctuating environmental, industrial, or chemical influences on your wastewater matrix
- Catchment size: small catchments tend to yield more variable results
So: more frequent sampling enables a quicker identification of trends
Trend: 4 data points, preferably; a 2-3x change two times in a row is also meaningful