How sensitive, reproducible, and reliable are GEArray results?
A number of different parameters define microarray sensitivity including limit of detection and linear dynamic range. The GEArray detects messages as rare as 3 copies per cell from one million cells including low abundant transcripts such as un-induced TP53, CDKN1A and BAX. They detect the presence of 10 fM (femtomolar) concentrations of labeled sample in the hybridization solution. These numbers translate into a mass ratio of 1:300,000 meaning that these arrays can detect the equivalent of one specific message among 300,000 irrelevant messages. We used these results to develop our recommendations for the minimum amount of input RNA required for performing an experiment: Only 1 microgram (or under some conditions even as little as 100 ng) of total RNA (or ten fold less mRNA) is needed to perform a microarray experiment. When preparing RNA from cell culture, one 80% confluent T-25 flask or 100mm dish usually contains this amount of RNA. If preparing RNA from tissue, 100 to 250 mg of tis
