chend@ucs.orst.edu (Donald Chen - Microbiology) (02/24/89)
Hi: Our lab has recently encountered a problem which we have narrowed down to the use of Costar EIA/RIA assay plates. We would like to know if anyone else has had similar problems. The problem: Please note that this does not apply to all plates within the same carton. However, when the problem does arise, the results are consistent. For a 96-well plate, and within any particular row (eg A-H) we would apply the same antigen-block with BSA- then coat with dilutions of sera (in quadruplicate, eg 10-1, 10-2, 10-3) We visualize with Mab(to IgG) that is biotinylated, streptavidin-HRPO, and ABTS. We read on an automated ELISA reader. When the results are printed, we notice that within a replicate (done in quadruplicate) the readings are low-high-low-high. Not all rows on a plate are affected. When we reverse the plate, the same pattern is seen (that is, if a well had a low reading in one orientation it had a low reading in the second orientation). When our PI called Costar, the rep at first indicated that our plates were from an old lot from last year. However, she backed off from that when we told her we had bought them last month from VWR. She did not comment on the possibility that the dies used to make the plates may have had deformities. We are now ordering plates from GIBCO to circumvent this problem. But we are concerned that other ELISA assays in our lab may also be affected, even though the sensitivity of the assays in those cases may not be as great as in this case. Any comments? Any solutions? Thanks for any help you can give us. Don Chen Dept of Microbiology Oregon State University Corvallis OR 97331 (503) 754-3189 chend@bionette.ucs.orst.edu Don Chen Dept of Microbiology Oregon State University Corvallis, OR 97331