definiens: shall mean transcription - based nucleic acid amplification, ' using reverse transcriptase, RNA polymerase anda, dded RNaseH, wherein :, ----J,.a;;;.;L ..,Jthe added RNase H molecule contains no enzyme activity found in reverse transcriptase, other than that of binding to the RNA and cleaving the RNA strand of an RNA : DNA duplexi ( b ) the added RNase H is presen~ at gr ~ ater than or equal to 0.00,1 ~u = n"'lc.-.!ro'liter ( where the unit definition ' and assay conditions are equivalent to those set f9rth below ) in the amplification reaction or, if present ill lesser amount, the extent of amplification achieved in the pres ~ nceof such added RNase H shall be at least 10 times greater than that achieved in the absence of such added RNase H ; an, ( c ) the amplification reaction is performed at a temperature below 55 ° C