Genomic Precision

 A SeraCare blog focused on precision medicine and advanced clinical diagnostics

This is the Number One Risk to Your Clinical Sequencing Assay

Critical missteps during the assay development phase can cause expensive delays and risk the quality of an assay. How can you be sure your bioinformatics pipeline is correctly calling variants?

Posted by Trevor on Oct 17, 2017 11:00:00 AM

If you’re relying on remnant patient samples to tell you how well your lab's bioinformatics pipeline can call clinically important variants, you might be missing more than you realize.

In our experience, the bioinformatics pipeline can be the weakest link in assay development for many labs. Just because a variant is sequenced correctly doesn’t always mean that it will be called. And false-positives are just as bad.

  • Sometimes it’s an issue of allele frequency. For example, we’ve seen cases where labs could detect certain mutations at 10% allele frequency, but as soon as the frequency dropped to 7%, they stopped detecting it.
  • Other cases are caused by the complexity of the variant. For example, even at low allele frequencies, a lab may pick up relatively easy-to-detect single-nucleotide variants (SNVs) but can have problems with insertion/deletion (INDEL) calling errors.

In both examples, the mutations aren’t missed because of sequencing or library preparation problems. As we’ve witnessed time and time again, when labs optimize their bioinformatics pipelines, they start picking up the low-frequency and difficult-to-detect variants again.

The catch is, you first have to know you’re missing something. In assay development, what you don’t know can seriously weaken your test.

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Topics: allele frequencies, next-generation sequencing, cancer profiling, bioinformatics

Is Your NGS-Based Assay on the Right TRK?

From extraction, to library prep, to sequencing, to the bioinformatics pipeline, there are countless points where something could go wrong.

Posted by Trevor on Oct 9, 2017 2:13:00 PM

Despite the absence of clear guidelines or firmly established best practices, next-generation sequencing (NGS) assays are becoming the method of choice for gene fusion detection.

This is significant because, although some of the cancers that contain fusion RNAs are rare, they’re now treatable thanks to new targeted therapies. If your assay can detect fusion RNAs, it can help profile tumors for important diagnostic, prognostic, and therapeutic targets, which can lead to improved patient outcomes.

The old FISH method limited you to one type of fusion variant at a time; it was effective, but also slow and cumbersome. With the latest NGS techniques, detecting fusion RNAs is more efficient than ever. It’s more sensitive and can detect multiple fusions in the same assay.

Nevertheless, it’s still challenging because of the complex workflows and the need to rigorously ensure performance across all fusion variants. From extraction, to library prep, to sequencing, to the bioinformatics pipeline, there are countless points where something could go wrong.

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Topics: NGS reference materials, QC Management Software, Rare variants, fusion RNA, next-generation sequencing

 
 

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