What factors are contributing to the sudden 30% increase in turnaround time for Natera's Signatera ctDNA assay results?

Introduction

The sudden 30% increase in turnaround time for Natera's Signatera ctDNA assay results 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.

I'll approach this problem by first clarifying key details, ruling out external factors, and then diving deep into the product ecosystem, metric breakdown, and data analysis. From there, I'll form hypotheses, conduct root cause analysis, and propose validation methods and solutions.

Step 1

Clarifying Questions (3 minutes)

• Looking at the timing, I'm thinking there might be a recent change in the assay process. Has there been any modification to the Signatera ctDNA assay workflow in the past month?

Why it matters: Recent changes often correlate with performance shifts. Expected answer: Yes, a new step was added to the workflow. Impact on approach: If yes, we'd focus on the new step's impact; if no, we'd look at other factors.

• Considering the magnitude of the increase, I'm wondering about sample volume. Has there been a significant increase in the number of samples processed recently?

Why it matters: Volume changes can strain capacity and increase turnaround time. Expected answer: Sample volume has increased by 20% in the last quarter. Impact on approach: If yes, we'd investigate capacity issues; if no, we'd look at other efficiency factors.

• Given the specificity of the issue, I'm curious about the affected stages. Is the 30% increase uniform across all stages of the assay process, or is it concentrated in specific steps?

Why it matters: Pinpointing the affected stages narrows down potential causes. Expected answer: The increase is primarily in the sequencing and analysis stages. Impact on approach: We'd focus our investigation on the identified stages if specific, or look at systemic issues if uniform.

• Considering potential data anomalies, I'm wondering about the measurement system. Has there been any change in how turnaround time is measured or reported?

Why it matters: Ensures we're dealing with a real issue, not a measurement artifact. Expected answer: No changes in measurement or reporting systems. Impact on approach: If changed, we'd scrutinize the new system; if not, we'd focus on actual performance issues.