Blind testing - Glossary - peptidetesting.cc

Blind testing (also known as blind proficiency testing or blind quality control) is a laboratory quality-control method in which samples with a known composition are hidden inside routine daily work. Analysts handle them like normal specimens, so the laboratory can observe its real-world error rate, not only its best-case performance on labeled standards.

Blind testing samples follow the standard laboratory workflow

The hidden sample passes through the usual workflow: receipt, preparation, analysis, and reporting. After the result is issued, the submitting party compares the reported value with the known true value. Any difference can show where the laboratory's process, equipment, staff work, or reporting failed.

When you judge a Certificate of Analysis (COA), documented blind testing is stronger evidence than accreditation alone. Standards such as ISO-IEC 17025 are valuable, but audits can miss specific day-to-day errors. Blind testing checks whether the COA reflects actual laboratory accuracy under normal conditions.

Analytical accuracy and precision
Adherence to standard operating procedures
Operator performance and equipment calibration
Clerical accuracy in data entry and reporting
Potential signs of bias or professional misconduct

Laboratory blind testing is distinct from clinical trial blinding

Laboratory blind testing is different from blinding in clinical trials, although the terms sound similar. In clinical research, blinding hides treatment allocation from participants or researchers, such as in single-blind or double-blind designs. In the laboratory, blind testing hides the sample's identity or expected result from the technician, so the quality-control process can be judged without that knowledge influencing the work.

Blind testing samples follow the standard laboratory workflow

Laboratory blind testing is distinct from clinical trial blinding

Sources