The London Bullion Market Association operates a proficiency testing scheme for gold and silver assayers, a program that underpins confidence in the purity and weight standards that global bullion markets depend on.
Accurate assaying — the chemical or physical process of determining the purity of a metal — sits at the foundation of the global gold and silver trade. When a bar is stamped 999.9 fine gold, that claim rests on the work of trained assayers using verified methods. The LBMA’s proficiency testing scheme exists to make sure those methods stay reliable across the laboratories that serve its Good Delivery network.
Under a proficiency testing program, participating laboratories receive identical reference samples and submit their results independently. The LBMA then compares those results against each other and against known values. Any lab whose readings fall outside acceptable tolerances can be identified, investigated, and required to correct its processes before its results are trusted in the market again.
This kind of external verification matters because gold and silver bars that carry LBMA Good Delivery status are accepted without re-testing at central banks, exchanges, and institutional vaults worldwide. The scheme functions as a quality-control backstop for a market that clears hundreds of billions of dollars in metal each year.
For buyers of investment-grade bullion, the indirect benefit is real. Products sourced from LBMA-accredited refiners carry assay credentials that have been tested against a global peer group, not just self-certified. That reduces the risk of purity disputes at the point of resale or redemption.
Proficiency testing is a routine but essential part of laboratory accreditation in commodities markets. The LBMA’s ongoing administration of such a scheme signals that the association continues to prioritize market integrity as a core function, alongside its role in price benchmarking and refiner oversight.
Consistent assay standards are easy to overlook until they fail — which is precisely why ongoing proficiency programs like this one deserve attention from anyone holding physical metal.
