Table 1.

Example Quality Indicators on RNA Processed from Frozen Tissue in Preparation for Expression Profiling of Cancer

Quality indicator	Description
1	The tissue specimen is rejected if there are not at least 30% malignant cells, as determined by a pathologist using microscopy
2	The RNA specimen is rejected if either of the following is true: A260/A280 is <1.8, as determined using Nanodrop (Wilmington, DE) spectrophotometry; or the RNA integrity no. is <6.5, as determined using an Agilent Bioanalyzer 2100
3	The labeled cRNA is rejected if either of the following is true based on results of Nanodrop fluorometry: there is <10 μg of amplified labeled cRNA or specific activity is <8 pmol Cy5/μg labeled cRNA

Quality indicators and limits of acceptability must be established using evidence gathered during validation studies for the particular test being developed.