What would you do after an out-of-specification laboratory result?

Why

First secure raw data, audit trails, chromatograms, sample handling records and instrument suitability evidence. Assess potential obvious errors promptly without inventing an assignment of cause. The initial laboratory investigation reviews calculations, standards, method execution, sample preparation and equipment, using a scientifically justified and documented retest strategy if applicable.

If no conclusive lab error explains the OOS, extend the investigation to manufacturing and affected batches. Avoid averaging inconsistent outcomes solely to make a specification pass, and evaluate impact on other lots and stability trends. Disposition belongs to the authorized quality process with clear conclusions and risk assessment.

The correct scope depends on the product, method and applicable procedure. A statistically improbable result still warrants investigation rather than deletion.