In cDNA microarray experiments, the measurement of interest is signal intensity ratio of spots. Each spot have four types of pixel intensities namely red foreground, green foreground, red background and green background. The uncertainty associated with the signal intensity ratio depends on the correlation between pixel intensities of spots. It is important to estimate these correlations of pixel intensities of spots to propagate the uncertainty associated with the intensity ratio as well as to address the systematic errors arise from the chip artifacts. The present study is a review to identify various methods to estimate the correlation of various pixel intensities of microarray spots. Articles published from 1994 to 2015 are searched in various databases like PubMed, Scopus, Web of Science, and Google Scholar. Six articles are selected for the review based on selection criteria. We observed that there is very little literature available which deals with the impotence of the correlation between various pixel intensities of microarray spots.
cDNA microarray, Pixel intensities, Intensity ratio, Correlation, Pixel correlations
