Synthetic siRNA detection method

1. A method for detecting a synthetic siRNA in which the 3′ end is a dT 1-4 nucleotide sequence, comprising:

(a) adding polydeoxyadenosine to the 3′ DNA end of at least one strand of the siRNA to be detected to produce a polydeoxyadenosine-added RNA;

(b) annealing a polydeoxythymidine primer having a tag sequence at its 5′ end to the polydeoxyadenosine-added RNA and synthesizing DNA from the primer by reverse transcription; and

(c) detecting the DNA synthesized in (b), wherein the polydeoxythymidine primer comprises in 3′ to 5′ direction a dT 1-4 nucleotide sequence, a polydeoxythymidine sequence, and the tag sequence, wherein the tag sequence distinguishes a polydeoxythymidine primer having the tag sequence at its 5′ end from a polydeoxythymidine primer without the tag sequence, and wherein the step of detecting is performed by a nucleic acid amplification in (c) using the synthesized DNA as a template, and using a first primer comprising a sequence homologous to the tag sequence and a second primer comprising a sequence homologous to the strand of the siRNA to which the polydeoxyadenosine is added.

2. The method of claim 1 , further comprising the step of quantifying the synthesized DNA to calculate an amount of the siRNA to which polydeoxyadenosine was added in (a).

3. The method of claim 1 , wherein the polydeoxyadenosine is added in step (a) by a terminal deoxynucleotidyl transferase.

4. The method of claim 1 , wherein the tag sequence is a universal tag sequence.

5. The method of claim 1 wherein 20 fM to 2 nM of siRNA can be measured.