Monoclonal antibody testing of lymphocytes after overnight storage

Often monoclonal antibody testing of lymphocytes is not performed until the day after blood collection for reasons of convenience or due to the need to transport the blood to other facilities. In order to determine whether accurate results can be obtained on the day after collection, we compared results obtained after storage overnight at 4 degrees C or 22 degrees C with results obtained with fresh lymphocytes. Lymphocytes from 24 normal individuals were evaluated with 10 monoclonal antibodies using an immunofluorescence technique with analysis by flow cytofluorometry. There were markedly altered results obtained with lymphocytes separated on the day after collection from whole blood stored at 4 degrees C. Lymphocytes separated from whole blood stored at 22 degrees C showed moderate changes in reactivity with some monoclonal antibodies. Lymphocytes that were separated from fresh blood and then stored at 4 degrees C or 22 degrees C showed results similar to fresh lymphocytes. These results underscore the importance of proper processing of blood samples to avoid misinterpretation of results.