How to Compare When COA and Retained Sample Results Differ?
Quick AnswerWhen comparing the COA against retained-sample results, verify sample identity, sampling and storage conditions, test method, units, and test date simultaneously; retain original values and recalculate any discrepancies.
Establish a Pairing Table
Bind each row to the same batch number and parameter, listing the original certificate, retained sample result, method, unit, and testing laboratory. If the date is unknown, state 'unknown'; do not arbitrarily label it as a re-test on a specific date.
Recalculation and Assessment
When calculating the difference, indicate the direction and retain original records. If the method or sample condition is inconsistent, a numerical discrepancy does not directly prove either party is at fault; when necessary, negotiate joint sampling and a third-party retest.
Sources & Further Reading
- RIOMI 橡胶业务编辑与项目经验（2026-10 编审）