# “On Bait” reads localized to ACCESS panel

![](https://2763969089-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-M52gq1rRSDQOKMQGEuR%2F-M9Z39Nd7c6cJRknLQBm%2F-M9Z5eq57iPNBxeZUEz7%2FScreen%20Shot%202020-06-11%20at%2011.58.22%20AM.png?alt=media\&token=53e7e4e5-6e23-4c16-85b1-af692cb025e6)

**Theoretical Method**

Divide the number of reads mapping to ACCESS genome bait regions by the sample’s total read count.&#x20;

{% hint style="info" %}
Note: This metric comes from the standard BAM
{% endhint %}

**Technical Methods**

* Tool Used:
  * waltz.jar CountReads
  * aggregate\_bam\_metrics.sh
  * tables\_module.py
  * plots\_module.r
* Input
  * ACCESS pool A and pool B bed files
  * Standard Bam (tables also produced for U / S / D bams)
* Output
  * Text file with the read count information: “sample\_id.bam.read-counts.txt”&#x20;
  * Text files for aggregated results “read-counts.txt”<br>

**Interpretations**\
Ideally should be between 60%-80% and should not drop below 50% for ctDNA samples (A + B targets combined). Because A and B targets are mixed in 50:1 ratio, there should be a larger on-target rate for the A targets. If the rate drops below 50%, with adequate read counts, this could be indicative of a bad capture.  For buffy coats, this is about 35%-45%.
