In theory this question generally depends on two factors:
- Sequencing coverage — the number of DNA sequences analyzed from the sample.
- The abundance of the target — at any coverage level, the more abundant targets are more likely to be detected than the rare targets.
We aim to sequence about 10,000 DNA sequences from each sample. In theory, based on binomial probability, we can be 99% confident that we would detect a target that makes up at least 0.05% of the sample. So only the rarest members of the community should escape our test.
In practice, one factor that can complicate this is the distribution of DNA sequences in the sample. If for some reason the sample is swamped with DNA from a single source, this can obscure the presence of rarer targets in the sample. This would be apparent in the sample composition plots in the report, and may call for re-sampling or re-sequencing if it occurs, to ensure we get a high-sensitivity test of your tank.