RNA spike-in

An RNA spike-in is an RNA transcript used to calibrate measurements in a DNA microarray experiment. Each spike-in is designed to hybridize with a specific control probe on the target array. Manufacturers of commercially available microarrays typically offer companion RNA spike-ins "kits".

Known amounts of RNA spike-ins are mixed with the experiment sample during preparation. Subsequently the measured degree of hybridization between the spike-ins and the control probes is used to normalize the hybridization measurements of the sample RNA.