Evaluation of a particle-enhanced turbidimetric immunoassay for the measurement of ferritin: application to patients participating in an autologous blood transfusion program

Objectives: To evaluate a turbidimetric immunoassay for the measurement of ferritin, and to assay this method in a group of patients undergoing an autologous blood transfusion program. Design and methods: We used an ILab 900 analyzer. This instrument automates a particle-enhanced immunoturbidimetric assay with an analysis time of 9 min. This technique was compared with a microparticle immunoassay. The turbidimetric assay was used to measure ferritin in a group of 30 patients undergoing an autologous blood transfusion program. Results: The assay was linear in the range 3–1400 μg/L (r = 0.9999). The intra- and inter-assay imprecision (CV) at 20, 97 and 469 μg/L were <3.0 and <5.0%, respectively. Recovery was 88.7 to 97.4%. The detection limit was 3 μg/L. Hemoglobin (≤4 g/L), mild hyperbilirubilinemia (bilirubin ≤50 μmol/L), triglycerides (≤10 mmol/L) and myeloma paraproteins did not interfere with the assay. The assay showed good correlation with a microparticle enzymoimmunoassay (r = 0.994) with a mean difference between methods of −6 ± 16 μg/L. This method was sensitive, accurate, and fast enough for an efficient follow-up of autologous blood transfusion patients. Conclusions: The new automated serum assay for ferritin is an attractive alternative that avoids the need for dedicated instrumentation.