title: Dried blood spot samples: optimization of commercial EIAs for hepatitis C antibody detection and stability under different storage conditions.
abstract: This study was undertaken to optimize and compare the efficiency of two commercial EIAs for anti-HCV detection (HCV Ab Radim, Pomezzia, Italy and ETI-AB-HCVK-4 DiaSorin, Vercelli, Italy), in dried blood spot (DBS) samples. The long-term stability of anti-HCV on DBS samples stored at three environmental conditions was also evaluated at: 2-8 °C, 20-25 °C, and -20 °C. Paired DBS and serum samples were obtained from individuals with or without anti-HCV. The type of elution buffer, sample and conjugate volume, sample incubation time and cut-off values were evaluated. For both EIAs, a larger sample volume was used, and the cut-off value determined by the manufacturer was employed for Radim EIA; however, ROC curve analysis was used for the DiaSorin EIA. The sensitivity and specificity of Radim EIA on DBS were 97.5% and 99.5%, respectively, and of DiaSorin EIA were 88.9% and 98.9%, respectively. Accurate results were obtained for a period of 117 days using DBS samples stored at all storage conditions, but storage at -20 °C resulted in the lowest variation among the absorbance values. Both EIAs demonstrated the same limit of detection (until dilution of 1:10(4) with estimated viral load of 3.1 × 10(-1) UI/ml), but the Radim EIA was associated with the best performance because a low coefficient of variation was observed in the repetition and reproducibility studies. In conclusion, commercial EIAs can be optimized for anti-HCV detection in DBS samples that are extremely stable at different conditions for more than 100 days.
authors.affiliation: Laboratory of Viral Hepatitis, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Brazil.
authors.forename: B L C
authors.initials: BL
authors.lastname: Marques
authors.forename: C U
authors.initials: CU
authors.lastname: Brandão
authors.forename: E F
authors.initials: EF
authors.lastname: Silva
authors.forename: V A
authors.initials: VA
authors.lastname: Marques
authors.forename: C A
authors.initials: CA
authors.lastname: Villela-Nogueira
authors.forename: K M R
authors.initials: KM
authors.lastname: Do Ó
authors.forename: M T
authors.initials: MT
authors.lastname: de Paula
authors.forename: L L
authors.initials: LL
authors.lastname: Lewis-Ximenez
authors.forename: E
authors.initials: E
authors.lastname: Lampe
authors.forename: L M
authors.initials: LM
authors.lastname: Villar
mesh_terms: D000328:Adult; D001769:Blood / Q000276:immunology*; D019411:Clinical Laboratory Techniques / Q000379:methods; D003890:Desiccation; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006526:Hepatitis C / Q000175:diagnosis*; D018937:Hepatitis C Antibodies / Q000097:blood*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012680:Sensitivity and Specificity; D013048:Specimen Handling / Q000379:methods*; D013696:Temperature; D055815:Young Adult
chemical_list: D018937:Hepatitis C Antibodies