Abstract
Background: Ferritin levels are used to make decisions on therapy of iron deficiency in patients with chronic kidney disease (CKD). Hyperferritinaemia, common among patients with CKD from the Northern Territory (NT) of Australia, makes use of ferritin levels as per clinical guidelines challenging. No gold standard assay exists for measuring ferritin levels. Significant variability between results from different assays creates challenges for clinical decision-making regarding iron therapy. In the NT, different laboratories use different methods. In 2018, Territory Pathology changed the assay from Abbott ARCHITECT i1000 (AA) to Ortho-Clinical Diagnostics Vitros 7600 (OCD). This was during the planning of the INtravenous iron polymaltose for First Nations Australian patients with high FERRitin levels on haemodialysis (INFERR) clinical trial. The trial design was based on AA assay ferritin levels. We compared the two assays’ level of agreement in measuring ferritin levels in CKD patients. Methods: Samples from INFERR clinical trial participants were analysed. Other samples from patients whose testing were completed the same day on OCD analyzers and run within 24 h on AA analyzers were added to ensure wide range of ferritin levels, adding statistical strength to the comparison. Ferritin levels from both assays were compared using Pearson’s correlation, Bland–Altman, Deming and Passing-Bablok regression analyses. Differences between sample types, plasma and serum were assessed. Results: Sixty-eight and 111 (179) samples from different patients from Central Australia and Top End of Australia, respectively, were analyzed separately and in combination. The ferritin levels ranged from 3.1 µg/L to 3354 µg/L and 3 µg/L to 2170 µg/L for AA and OCD assays respectively. Using Bland–Altman, Deming and Passing-Bablok regression methods for comparison, ferritin results were consistently 36% to 44% higher with AA than OCD assays. The bias was up to 49%. AA ferritin results were the same in serum and plasma. However, OCD ferritin results were 5% higher in serum than plasma. Conclusions: When making clinical decisions, using ferritin results from the same assay in patients with CKD is critical. If the assay is changed, it is essential to assess agreement between results from the new and old assays. Further studies to harmonize ferritin assays are required.
| Original language | English |
|---|---|
| Article number | 198 |
| Pages (from-to) | 1-10 |
| Number of pages | 10 |
| Journal | BMC Nephrology |
| Volume | 24 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - Dec 2023 |
Bibliographical note
Funding Information:The funding for the INFERR clinical trial is from The National Health and Medical Research Council of Australia (NHMRC, Project Grant no.1163841). There were no other funding sources to declare.
Funding Information:
The authors gratefully acknowledge the support of the INFERR trial participants and participants who contributed the Laboratory QA and other samples, all laboratory staff, renal teams across the NT, study staff and partner organizations (including Fresenius Kidney Care Australia). We thank Mr. Mark Mayo, Ms. Stephanie Young and Ms. Cheryl Ross and the INFERR clinical trial Indigenous Reference groups in Central Australia and the Top End of Australia for their critical role in the proper conduct of the INFERR clinical trial. The INFERR Study Group and the INFERR clinical trial independent Data Safety and Monitoring Board (DSMB) are contributing immensely to the conduct and progress of the INFERR clinical trial.
Publisher Copyright:
© 2023, Crown.