LongSAGE was a more robust version of the original SAGE developed in 2002 which had a higher throughput, using 20 μg of mRNA to generate a cDNA library of thousands of tags. Robust LongSage (RL-SAGE) Further improved on the LongSAGE protocol with the ability to generate a library with an insert size of 50 ng mRNA, much smaller than previous LongSAGE insert size of 2 μg mRNA and using a lower number of ditag polymerase chain reactions (PCR) to obtain a complete cDNA library.