Written by: Dr. Wolfgang Pitsch

What is your first reaction in the Quality department?

Okay… let’s be honest: the first thought is often, “Oh no. This is going to be messy.” But after that initial gut punch, what happens next defines your quality culture.

Step 1: Pause and Think

The instinct to “fix the number” is strong. Many teams jump straight to retesting because it feels like action. But here’s the question: If the original result had been within specification, would you have rerun the test? No. So why now?

Step 2: Understand the Regulatory Expectation

Both FDA Guidance for Industry and EudraLex Volume 4, Chapter 6 are clear:

The expected next step is not to retest blindly. It is to investigate!

A second test without a hypothesis gives you no new knowledge. If the retest passes, it might just reflect natural variation. If you average the two results into compliance, you still don’t know what went wrong with your product or your process. That’s not science—that’s gambling.

Step 3: Quality Is Not About Numbers

Quality is not about making data look good. It’s about understanding reality. An Out-of-Specification (OOS) result is a signal. It’s telling you something about your system or process—maybe your method, maybe your material, maybe your environment. Your job is to listen.

Step 4: Investigate with Purpose

Start with a structured investigation. Build your hypothesis before you touch the sample again. Ask:


  • Was the method executed correctly?
  • Were instruments calibrated and within tolerance?
  • Could there be a sample mix-up or contamination?
  • Is there a trend in similar batches or lots?
  • Were there any deviations or unexpected situations during your production?


Document every step. Your investigation should be reproducible and defensible. This is where quality culture shows: do you treat OOS as a learning opportunity or as a nuisance?

Example Scenario

Imagine you’re producing a therapeutic radiopharmaceutical. The radiochemical purity test comes back at 88%, below the 90% specification. Instead of rushing to rerun the test, you:


  • Quarantine the batch.
  • Review the chromatogram for anomalies.
  • Check the column performance and mobile phase preparation.
  • Compare with historical data—was there a drift over the last five lots?
  • Interview the analyst: any deviations from SOP?
  • Interview production: any deviations from SOP?


Only after forming a hypothesis—say, “Column degradation due to extended use”—do you design a confirmatory test. That’s science. That’s compliance. That’s culture.

The Qualificiency Way

We teach that OOS is not a failure—it’s feedback. A mature quality system doesn’t panic or hide. It investigates, learns, and improves. Because in GMP environments, trust is built on transparency and rigor, not on quick fixes.

#GMP #QualityCulture #RootCauseAnalysis #OOS #Pharma #Radiopharma #QualificiencyWay #ComplianceToCulture