![[Article Title]](https://media.americanpharmaceuticalreview.com/m/28/article/627895-134x100.jpg)
A sterility test failure should never be viewed as an isolated laboratory result. Sterility testing is destructive and limited to a small subset of units, so a passing test cannot prove a batch is sterile and a failed test cannot show when or where contamination was introduced. This article explains how a risk-based, qualified, and well-trended environmental monitoring program becomes the primary source of evidence in aseptic sterility test failure investigations.