Durability of direct immunofluorescence (DIF) slides stored at room temperature

Abstract

Background: Prior studies suggested that direct immunofluorescence (DIF) slides can be stored at room temperature.

Objectives: We sought to determine the durability of DIF slides stored at room temperature for 5 years.

Methods: This was a retrospective study of 83 DIF slides archived at room temperature during 2010. The pattern of immunoreactants was compared with those noted in the original report.

Results: Loss of reactivity was limited to cases with weak fluorescence at original diagnosis. Loss of IgG was noted in 12.5% of cases, IgA in 12%, C3 in 10%, and IgM in 9.75%. Fibrin showed no loss of reactivity. Preservation of immunofluorescence was not related to site of deposition. Overall, a reliable diagnosis could be made in 75 of 79 archived cases (94.9%).

Limitations: Cases had been archived for periods varying from 4.5 to 5 years. Variations in processing and fluorochromes could affect durability. We have no way of knowing how long slides had been exposed to ultraviolet light at the time of initial examination.

Conclusion: DIF showed excellent durability in slides kept at room temperature for 5 years.

Keywords: direct immunofluorescence; room temperature; storing.