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Background Different laboratory methods are used to quantify ferritin concentrations as a marker of iron status. A systematic review was undertaken to assess the accuracy and comparability of the most used methods for ferritin detection. Methods and findings National and regional 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 to date. The analysis included the comparison between at least 2 methods detailing: sensitivity, precision, accuracy, predictive values, inter-methods adjustment, and use of international reference materials. Pooled method performance was analyzed for each method and across methods. Outcomes Search strategy identified 11893 records. After de-duplication and screening 252 studies were assessed, including 187 studies in the qualitative analysis and 148 in the meta-analysis. The most used methods included radiometric, nonradiometric and agglutination assays. The overall within-run imprecision for the most reported ferritin methods was 6.2±3.4% (CI 5.69–6.70%; n = 171), between-run imprecision 8.9±8.7% (CI 7.44–10.35%; n = 136), and recovery rate 95.6% (CI 91.5–99.7%; n = 94). The pooled regression coefficient was 0.985 among all methods analyzed, and 0.984 when comparing nonradiometric and radiometric methods, without statistical differences in ferritin concentration ranging from 2.3 to 1454 µµg/L. Conclusion The laboratory methods most used to determine ferritin concentrations have comparable accuracy and performance. Registered in PROSPERO CRD42016036222.

Una de las técnicas con colorantes catiónicos (azul de dimetilmetileno) utilizadas en los laboratorios clínicos para el screening de mucopolisacaridosis recomienda la precipitación de los GAG o mucopolisacáridos con CPC. En este trabajo se introdujo una modificación que consistió en eliminar la fase de precipitación, con objeto de evitar las posibles pérdidas de muestra que pudieran tener lugar con las sucesivas decantaciones en las orinas con valores elevados y en las de valores más bajos, aparte de la simplificación que representa para la técnica. Los resultados confirmaron la hipótesis, encontrándose diferencias significativas (p