The Sentrix® HumanRef-8RD BeadChip is an early-access version of a multi-sample, gene expression microarray with content derived from the NCBI RefSeq database. Designed to interrogate over 23,000 transcripts per array, probe content was optimized prior to commercial release and the first-generation research product (8RD) was subsequently replaced by the HumanRef-8 BeadChip. Researchers can generate genome-wide expression profiles for eight samples in parallel on the BeadChip. Each array on the BeadChip is composed of 3-micron features with 30-fold average feature redundancy. Every features is quality-controlled during array manufacturing. Probes are fully screened, full-length 50-mers. Assay requires 50-100ng of total RNA input.