Preservation of nucleic acids for polymerase chain reaction after prolonged storage at room temperature

A guanidinium isothiocyanate (GITC) lysis solution was evaluated for its ef ficacy in preserving nucleic acids for subsequent analysis after prolonged storage at room temperature. Aliquots of thyroid crude cell lysates were st ored at 22 degrees C for 8 weeks in the GITC solution. Crude cell lysates s tored for 2 weeks in the GITC solution consistently provided adequate RNA a nd DNA for reverse transcriptase-polymerase chain reaction (RT-PCR) and PCR , respectively, of PZ-microglobulin, thyroid stimulating hormone receptor ( TSHR), and thyroglobulin. Interestingly, the thyroglobulin and TSHR message s from thyroid fine needle aspirate samples were detected by RT-PCR only wh en stored at room temperature for less than 1 week, whereas the RT-PCR prod uct for beta 2-microglobulin was detectable in 95%, of the samples at 3 mon ths. In addition, thyroglobulin DNA was amplified by PCR in nearly all samp les stored at 22 degrees C fur 2 months. These data suggest that GITC solut ions can be used to preserve nucleic acids in most circumstances until tran sported to laboratories equipped and staffed with appropriate resources.