The Illumina NextSeq 550Dx instrument is intended for sequencing DNA libraries prepared by adding sample indices and capture sequences to amplified targets. These libraries are captured on a flow cell and sequenced on the instrument using sequencing by synthesis (SBS) chemistry. SBS chemistry uses a reversible-terminator method to detect single nucleotide bases incorporated into growing DNA strands. Instrument software performs image analysis and base calling, assigning a quality score to each base for each sequencing cycle. When primary analysis finishes, secondary analysis processes base calls on the instrument. The NextSeq 550Dx instrument uses different secondary analysis modules depending on the workflow. For the germline or somatic variant calling modules, data processing includes de-multiplexing, FASTQ file generation, alignment, variant calling, and generation of variant call format (VCF) files containing information regarding variants found at specific positions in a reference genome.
A mains electricity (AC-powered) automated laboratory instrument intended to determine the sequence of nucleotides in a nucleic acid library [pre-constructed from deoxyribonucleic acid (DNA) or ribonucleic acid (RNA)] for genetic analysis of a clinical specimen, using a next-generation sequencing (NGS) technique. It consists of a detector (e.g., fluorescent, luminescent or electrochemical) which detects signals from incorporated nucleotides, as well as sample processing, data processing, and/or data display software. It operates with minimal technician input and complete automation of all procedural steps.