Quality Control (Lab and Lot Release)
Quality Control tests laboratory testing, out-of-specification (OOS) investigation and lot release, especially for products requiring batch-by-batch control.
Laboratory rules
Samples must be collected, transported and stored under controlled conditions with chain-of-custody records. Testing uses validated methods and pharmacopoeial or approved specifications: identity, assay, dissolution, uniformity, sterility, endotoxin, pH and related substances as applicable. Equipment must be calibrated, reagents and reference standards must be in date, and raw data must be attributable, contemporaneous and secure. An OOS result triggers a formal investigation before any retest. Retesting is not permitted simply to obtain a passing result. For vaccines and other biologics, lot release relies on manufacturer batch records, quality control summaries and national control laboratory review before distribution.
Worked example
A batch fails dissolution at the 30-minute specification. The analyst does not immediately retest until a pass appears. The laboratory first conducts an OOS investigation: checks method, apparatus calibration, media preparation and sample handling. If a laboratory error is established, a justified retest may be performed; if the product itself fails, the batch is rejected and not released. The reasoning is that repeated testing without investigation masks product defects and undermines data integrity.
Traps that cost marks
- Retesting until a passing result is obtained.
- Skipping the OOS investigation or closing it without root cause.
- Using expired reagents, standards or calibration.
- Breaking chain of custody for samples.
- Releasing a batch before lot-release requirements are met.
- Recording data after the fact or without attribution.