Prenatal screening and diagnostic system and method

摘要

A screening system to process a biological sample in a wet-laboratory arrangement to determine a presence of cell-free DNA (cfDNA) fragments therein, to sequence the DNA fragments, and to use a data processing arrangement to compare information representative of the sequenced DNA fragments against information stored in a genomic database arrangement to provide an assessment score in respect of the biological sample. The screening system is operable to apply a modification to one or more uncertainty metrics associated with the information representative of the sequenced DNA fragments using secondary information provided to the screening system to reduce a stochastic and/or systemic uncertainty present in the assessment score. This may distinguish between cell-free DNA fragments of maternal, placental or fetal origin, using genome locality scores for mutations, sequence error scores for a given nucleic acid base, patient or mosaicism. This allows weighting to modify the confidence of a call. Biological samples containing cfDNA fragments may be extracted from a pregnant woman non-invasively.