March 2021

New reference material from NML at LGC for Blood – Hip replacement wear metals - Cr and Co

The UK’s National Measurement Laboratory (NML) at LGC has expanded its portfolio of reference materials to include a new material, LGC8276 Blood – Hip replacement wear metals - Cr and Co, with values traceable to the SI (International System of Units).

Approximately 71,000 UK patients have had a metal-on-metal hip device implanted or had metal-on-metal resurfacing. The United Kingdom’s MHRA (Medicines & Healthcare products Regulatory Agency) issued a medical device alert in 2012 (MDA/2012/036), updated in 2017 (MDA/2017/018), recommending that individuals implanted with metal-on-metal (MoM) hip replacements should be monitored. If the joint is deteriorating, this may cause soft tissue reactions and lead to an increase of chromium and/or cobalt in the blood, so patients should have regular reviews to assist early detection. Levels above 7 microgram per kilogram of either chromium or cobalt indicate the need for further investigation.

The NML, in collaboration with the UK’s Trace Elements External Quality Assessment Scheme (TEQAS), has produced a certified reference material (CRM) for both chromium and cobalt in whole blood at the MHRA action level. This can be used by laboratories as part of their quality assurance system when measuring these elements at these challenging low levels either for method validation or during routine monitoring. The certified values were obtained using measurements carried out at the NML facilities in Teddington, UK, under ISO/IEC 17025 accreditation and the certificate also provides indicative values for the levels of molybdenum, nickel and titanium. The production of this CRM is within the scope of LGC’s ISO 17034:2016 accreditation as a reference material producer.

Despite the clinical need for these measurements, there are very few suitable reference materials on the market. Ultimately, this CRM will improve the quality of the measurements of chromium and cobalt in blood performed in the UK and elsewhere, thus improving patients’ quality of life.

The hip replacement wear metals CRM is available to purchase from LGC Standards (product reference LGC8276).