PT  - JOURNAL ARTICLE
AU  - Raghav Saini
AU  - Pam Railton
AU  - Jessica Boyd
AU  - Hossein Sadrzadeh
AU  - James N. Powell
TI  - Concordance between laboratories in metal ion testing in patients with metal-on-metal hip implants
AID  - 10.1503/cjs.015717
DP  - 2019 Feb 01
TA  - Canadian Journal of Surgery
PG  - 9--13
VI  - 62
IP  - 1
4099  - http://canjsurg.ca/content/62/1/9.short
4100  - http://canjsurg.ca/content/62/1/9.full
SO  - CAN J SURG2019 Feb 01; 62
AB  - Background: Testing of whole blood or serum metal ion levels has become an important part of assessing and monitoring the performance of metal-on-metal bearings, both in hip resurfacing arthroplasty and in total hip replacement. The aim of this study was to determine the concordance between 2 laboratories testing cobalt and chromium ion levels in patients with metal-on-metal bearings.Methods: Serum and whole blood samples from patients who had undergone metal-on-metal resurfacing or large-diameter total hip arthroplasty were tested for cobalt and chromium ions in laboratory A (a recognized laboratory) and laboratory B (tasked with testing clinical specimens). Laboratory A performed cobalt and chromium testing on whole blood, and laboratory B performed cobalt testing on whole blood and chromium testing on serum.Results: Samples from 104 patients were tested. Laboratory B reported lower whole blood cobalt levels than laboratory A. Furthermore, laboratory A reported that all patients had elevated whole blood cobalt ion levels compared to the normal reference values for the laboratory, whereas laboratory B reported that 46 patients (44.2%) had whole blood cobalt ion levels within the normal reference range for the laboratory.Conclusion: This comparative study highlights the importance of using a single laboratory for metal ion testing, as values generated from different laboratories may not be directly comparable. With recent literature suggesting that whole blood cobalt levels as low as 1 ppb may be a predictor of adverse reactions to metal debris, accurate clinical measurement needs to be increasingly exact.