Cyclosporin A Measured in Plasma in Various Transplant Types by HPLC and Radloimmunoassay,

HPLC methods for measurement of cyclosporin A (CsA) in plasma are very specific but are labor intensive, have a low throughput, and usually require several sets of equip-ment to provide an adequate clinical service. Recently, an RIA (CYCLO-Trac) has been introduced by INCSTAR Corp. (Stillwater, MN 55082), which involves use of a monoclonal antibody against CsA developed by Sandoz Ltd. (Basle, Switzerland) and an 1251-labeled cyclosporine hg-and. To overcome the time-consuming aspects of HPLC, we decided to see if the CYCLO-Trac SP RIA kit supplied by INCSTAR Corp. could be substituted for HPLC in a medi-cal center dealing with a variety of transplant types. Our HPLC procedure involved a modification of a method previously described (1). Its detection limit for CsA was 10 zg/L, the range of assay linearity was 25 to 500 zg/L, mea