Poster Topical Area: Biomarkers
Poster Board Number: 140
Objective: Since ferritin concentration is widely used as a marker of iron stores and status, it is important to determine if ferritin methods are capable of detecting and discriminating iron statuses. The objective was to assess the accuracy and comparability of the most used methods for ferritin detection.
Methods: Cochrane Central Register of Controlled Trials, MEDLINE, Embase, CINAHL, Science Citation Index and others databases were searched for prospective, retrospective, sectional, longitudinal and case-control studies containing the characteristics and performance of at least one method for serum/plasma ferritin determinations in humans, published between 1950 and 2014. The primary outcome was the comparison between at least 2 methods detailing: sensitivity, precision, accuracy, predictive values, inter-methods adjustment, and use of international reference materials. This review is part of a project for retrieving, summarizing and assessing the evidence to inform WHO recommendations on the use and interpretation of ferritin concentrations for assessing iron status in populations. Results: From 240 records extracted, 174 studies were included in the qualitative analysis and 136 in the meta-analysis. The most used methods included enzyme immunoassays (e.g. ELISA and chemiluminiscent), radioactive (i.e. RIA and IRMA) and based on light passage (i.e. turbidimetric and nephelometric). The overall within-assay variation for the most reported ferritin methods was 6.3±3.4% (CI 5.75- 6.80%; n=160), between-assay variation 9.0±8.8% (CI 7.47- 10.48 %; n=131), and recovery rate 98.4±13.4% (CI 95.67- 101.07%; n=94). The regression coefficient was 0.985 between all methods analyzed, and 0.984 when comparing enzymatic and radioactive methods, without statistical differences in concentration ranges from 2.9 to 2173 mg/L.
Conclusions: The results from this review show that the methods used to determine ferritin are comparable and there is not preferred /recommended method, although the risk for radioactive contamination and expensive equipment are important drawbacks of RIA and IRMA. For patient follow-up, public health surveys or evaluations of impact of interventions, it is recommended to use the same ferritin method for the duration of the intervention.
World Health Organization
Geneve, Geneve, Switzerland