Majoni, Sandawana William

Nelson, Jane

Graham, Jessica

Abeyaratne, Asanga

Fernandes, David

Sajiv, Cherian

Rathnayake, Geetha

Ashford, Jenna

Hocking, Lyn

Cain, Heather

McFarlane, Robert

Lawton, P

Barzi, Federica

Taylor, Sean

Cass, Alan

2023-06-30

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.

Menzies School of Health Research, Charles Darwin University, Northern Territory, Darwin, Australia. sandawanaw@aol.com.

Department of Nephrology, Royal Darwin Hospital, Division of Medicine, P.O. Box 41326, Casuarina, Darwin, Northern Territory, Australia. sandawanaw@aol.com.

Northern Territory Medical Program, Flinders University, Darwin, Northern Territory, Australia. sandawanaw@aol.com.

Menzies School of Health Research, Charles Darwin University, Northern Territory, Darwin, Australia.

Department of Nephrology, Royal Darwin Hospital, Division of Medicine, P.O. Box 41326, Casuarina, Darwin, Northern Territory, Australia.

Northern Territory Medical Program, Flinders University, Darwin, Northern Territory, Australia.

Department of Nephrology, Alice Springs Hospital, Alice Springs, Northern Territory, Australia.

Territory Pathology, Darwin Northern Territory, Darwin, Australia.

Territory Pathology, Alice Springs, Northern Territory, Australia.

Poche Centre for Indigenous Health, The University of Queensland, Brisbane, QLD, Australia.

BMC Nephrol. 2023 Jun 30;24(1):198. doi: 10.1186/s12882-023-03255-6.

https://pubmed.ncbi.nlm.nih.gov/37391713/?otool=iaurydwlib

https://hdl.handle.net/10137/12489

24

Humans

*Plasma

Administration, Intravenous

*Clinical Decision-Making

Ferritins

Northern Territory

Comparison of two ferritin assay platforms to assess their level of agreement in measuring serum and plasma ferritin levels in patients with chronic kidney disease.

Journal Article

Publication