Why has Personalis's NeXT Personal assay seen a 15% decrease in sample throughput over the past month?

Introduction

The recent 15% decrease in sample throughput for Personalis's NeXT Personal assay over the past month is a critical issue that demands immediate attention. This analysis will systematically identify, validate, and address the root cause while considering both short-term and long-term implications for the product and company.

To tackle this problem, I'll follow a structured approach that covers issue identification, hypothesis generation, validation, and solution development. My goal is to provide a comprehensive analysis that not only resolves the current throughput issue but also strengthens our overall product performance and reliability.

Step 1

Clarifying Questions (3 minutes)

• Looking at the timing, I'm thinking there might be a recent change in our lab processes. Have there been any updates to our sample processing protocols in the last 1-2 months?

Why it matters: Changes in protocols could directly impact throughput. Expected answer: Yes, we implemented a new quality control step. Impact on approach: If confirmed, we'd focus on optimizing the new process.

• Considering the specificity of the 15% decrease, I'm wondering about our measurement accuracy. Has there been any change in how we're calculating or reporting throughput?

Why it matters: Ensures we're addressing a real issue, not a measurement artifact. Expected answer: No changes in calculation methods. Impact on approach: If there were changes, we'd need to reassess our baseline metrics.

• Given the nature of our assay, I'm curious about sample quality. Have we seen any shifts in the types or sources of samples we're receiving?

Why it matters: Sample variability could affect processing time and success rates. Expected answer: We've started accepting samples from a new clinical partner. Impact on approach: If confirmed, we'd investigate the new sample characteristics and adjust our processes accordingly.

• Thinking about our end-to-end process, I'm wondering about our equipment. Have there been any recent maintenance issues or equipment changes in our lab?

Why it matters: Equipment problems could directly impact throughput. Expected answer: We've had some intermittent issues with one of our sequencers. Impact on approach: If confirmed, we'd prioritize equipment troubleshooting and maintenance.