[Primary antisera before and after the expiration date. Comparative immunohistochemical observations and analysis of...

By means of positive and negative controls, the immunostaining properties of a series (B) of 78 primary antibodies (PAB) that had expired 7-77 months previously (mean, 26.3 months) were evaluated in comparison those of the same non expired (functioning) PAB. Qualitatively, no significative difference was observed in the specificity and sensitivity. Among all of the PAB (with the exception of one), no immunonegativity was observed. With special reference to immunohistochemical methods, dilution and retrieval procedures, as suggested on data sheets, were additionally considered. Moreover the residual availability of the reagents was checked. In fact 58 PAB were still available for further examination with probable prolongation of the duration of validity. Other observations are analytically reported as far as polyclonal, monoclonal, concentrated and predilluted expired PAB are concerned. In the same way, duration of available validity before the expiration date was examined for the expired PAB and for an additional series of 90 nonexpired PAB. Finally textual information (including intended use) reported on data sheets and labels has been scrutinized in detail. In conclusion, for the diagnostically applied immunohistochemistry on the basis of these findings and the recent American and European rules, the following propositions should be considered: (1) surveillance on methodological technical approach and diagnostic evaluation, with emphasis on accurate standardization and primary responsibility of the pathologist; (2) opportunity of a continuous feed-back between laboratories-customers and producers-traders, in order to render more uniform the information and establish more realistic parameters of utilization; and (3) possibility of cost reduction according to limited financial support from the health care administration.