Long‐term preservation of direct immunofluorescence staining in slides stored at room temperature

Abstract

To determine whether reproducible results from direct immunofluorescent tissue staining could be obtained after storing the slides at room temperature. We examined the original slides of 22 cases noted to be positive for direct immunofluorescence. Diagnoses include pemphigus, pemphigoid, lupus, dermatitis herpetiformis, lichen planus, and vasculitis. These specimens, initially evaluated during the period January 1997 to September 1998, were prepared with a standard immunofluorescence staining technique, and then a permanent aqueous mounting medium was added. All specimens were stored at room temperature in vertical slide holding trays. We focused on the presence and relative intensity of the immunofluorescence staining, as well as the final diagnosis. We then compared our readings to that of the original reports. Twenty of the 22 cases studied (91%) were read as having the same diagnosis as the initial immunopathology report. Seventeen of the 22 cases (77%) were found to have the identical or slightly less fluorescence intensity. The original reports in 3 of the cases did not comment on the original intensity of fluorescence. Thus, a comparison of fluorescence preservation could not be made. In 2 of the cases, the quality of tissue preservation was poor, and though fluorescent staining was noted, we were unable to render a diagnosis. Our results suggest that direct immunofluorescent studies, using a permanent aqueous mounting medium, can be stored over long periods of time at room temperature without significant degradation of staining.

The reliability of long‐term storage of direct immunofluorescent staining slides at room temperature

“…Various studies have been reported regarding the storage of DIF‐staining slides mounted with semipermanent mounting medium without losses of fluorescence 7,8,12,13 . Couser and Lewis 13 have proposed that kidney tissue slides may be stored for more than 2 years at 4°C, with no alteration in fluorescence intensity.…”

“…Couser and Lewis 13 have proposed that kidney tissue slides may be stored for more than 2 years at 4°C, with no alteration in fluorescence intensity. Grimwood and Proffer 12 have used a ready‐to‐use permanent mounting medium and examined DIF‐positive slides from skin tissues of 22 patients over a period ranging from 6 to 30 months. They have reported that six slides could be stored for more than 18 months at room temperature with minimal loss of fluorescence.…”

“…In most studies concerning alterations in fluorescence intensity, the effects of different mounting media 6,7,10,11 and different fluorochromes, 1,11 and the dose response effects of light exposure 3,7 have been tested by using a certain antibody with cultured cells, 3 artificial test substrate, 7 and rat 6 and human 7,10 tissue sections. Only a few studies have investigated the effect of storage time in daily practice in the laboratory 8,12,13 . In some of these studies, it has been stated that the diagnostic pattern is not altered, resulting in either minimal or no loss of fluorescence intensity for more than 2 years 12,13 .…”

“…Various studies have been reported regarding the storage of DIF-staining slides mounted with semipermanent mounting medium without losses of fluorescence. 7,8,12,13 Couser and Lewis 13 have proposed that kidney tissue slides may be stored for more than 2 years at 4 C, with no alteration in fluorescence intensity. Grimwood and Proffer 12 have used a ready-touse permanent mounting medium and examined DIF-positive slides from skin tissues of 22 patients over a period ranging from 6 to 30 months.…”

“…It has been proposed that DIF slides mounted with these mountants can be stored at room temperature for long periods. Grimwood and Proffer 12 showed that DIF‐positive slides could be preserved at room temperature for 30 months using this methodology. Storage of DIF slides at room temperature is easy and preferable; however, reports about the appropriate storage time of fluorescent‐staining slides at room temperature without losing diagnostic features are few and insufficient.…”