Preliminary evaluation of the performance of a new, highly sensitive commercial immunoassay for serum ferritin determination.
We evaluated the analytical performance of a new, commercial, fully automated immunoturbidimetric assay for the determination of ferritin [FER-Latex(X2)CN SEIKEN, Denka Seiken, Japan] in serum on the Olympus AU2700 analyzer. The new assay is a latex-enhanced turbidimetric immunoassay with an analysis time of 10 min. The linearity of the assay was confirmed up to 2505 pmol/L (R2=0.999). The detection limit and the functional sensitivity were both 4.5 pmol/L. The intra- and inter-assay imprecision (CV) at 67, 506, 2186 pmol/L was < 1.8% and < 2.5%, respectively. Verification of the traceability to a WHO standard (80/578) showed a recovery of 102.6% (target value 449 pmol/L). No hook effect was observed in samples containing up to 33,705 pmol/L. The assay showed good correlation with the Beckman Immage nephelometric system (r=0.999). Hemoglobin (< or = 9.8 g/L), total bilirubin (< or = 113 micromol/L), conjugated bilirubin (< or = 109 micromol/L) and rheumatoid factor (< or = 5.2x10(5) IU/L) did not interfere with the assay. The reference interval (2.5-97.5 percentile) was 72-521 pmol/L for men and 27-267 pmol/L for women. The reference interval in patients with anemia, malignant tumors and hemochromatosis was 5.6-52, 130-2436 and 1465-2903 pmol/L, respectively. On the basis of the receiver operating characteristic curve, the 90% sensitivity cut-off value to distinguish between patients with and without iron deficiency was 40 pmol/L. The new latex turbidimetric procedure for ferritin assay is an attractive alternative that avoids the need for dedicated instrumentation.
Signò
Paolo
P
Laboratorio di Analisi, Ospedale di Circolo, Varese, Italy.
Barassi
Alessandra
A
Novario
Raffaele
R
Melzi d'Eril
Gian Vico
GV
D000328:Adult; D018798:Anemia, Iron-Deficiency / Q000097:blood; D001774:Blood Chemical Analysis / Q000379:methods* / Q000592:standards / Q000706:statistics & numerical data*; D005260:Female; D005293:Ferritins / Q000097:blood* / Q000592:standards; D006432:Hemochromatosis / Q000097:blood; D006801:Humans; D007118:Immunoassay / Q000379:methods* / Q000592:standards / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000097:blood; D012372:ROC Curve; D012015:Reference Standards; D012016:Reference Values; D012680:Sensitivity and Specificity
D005293:Ferritins