Genomic Precision

 A SeraCare blog focused on precision medicine and advanced clinical diagnostics

Trevor

Recent Posts

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

Prevent Assay Drift In Your Clinical NGS Assay by Avoiding 2 Common Mistakes

Daily variations in your test performance can cause assay failure and may lead to false positives. Do you have the tools to detect them?

Posted by Trevor on Apr 27, 2017 3:00:00 PM

 

Clinical NGS tests may be powerful diagnostic tools for your molecular pathology laboratory, but they remain complex amalgamations of different hardware, reagents, and software systems — often from several different vendors and with different levels of quality. Only one of these critical reagents or systems has to fail or underperform in an assay to cause performance drift.

If you don’t catch assay drift quickly enough, it can lead to assay failures such as false positives or unexpected changes to assay performance — such as those that impact limit of detection (LoD).

How can your lab protect itself better? Avoid these two common mistakes:

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Topics: NGS assays, Common Lab Mistakes, Assay Drift

LDT Oversight: Why the FDA makes a point

Laboratory-developed tests are in the spotlight by the US Food and Drug Administration

Posted by Trevor on Dec 21, 2015 1:23:00 PM

Recently, the FDA upped the ante in the ongoing debate over its desire to regulate laboratory developed tests (LDTs) with the release of a report detailing the ‘real and potential harms to patients and to public health’ arising from LDTs.  This debate has been heating up for several years now—not coincidentally with the emergence of precision medicine and the rapid adoption of data-intensive tools such as Next Generation Sequencing (NGS) and the growing pipelines of targeted therapeutics.  One might argue that the horse has already left the barn and the FDA are trying to corral it back in.

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Topics: LDT, FDA, Reference Material

 
 

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