We are generating a panel of HTLV-II pedigreed serum/plasma reagents as a research panel to be used to evaluate performance of test kits. The panel is being assembled using both contributed specimens as well as purchased specimens. The specimens were determined to contain antibodies by reactivity on certain licensed or experimental tests. The presence of antibody was confirmed using a combination of western blot and RIPA. Cells from individuals were determined to be infected using PCR. The samples were determined to be HTLV-II by typing methods including the use of typing test kits and PCR. We are evaluating the performance of this panel on licensed HTLV-I tests as well as tests under review. Preliminary results using this panel were presented to the FDA Blood Products Advisory Committee in March 1993. Our results indicated a wide range in the ability of licensed HTLV-I tests to detect HTLV-II specimens. We are continuing to assemble pedigreed HTLV-II reagents.