During sequencing, each base called in a read is assigned a Q score. Higher Q scores indicate a smaller probability of error. For example, a Q score of 30 (Q30) indicates the probability of an incorrect base call is 1 in 1000 or a base call accuracy of 99.9%.

Sequencing on the Instrument has been designed to deliver a base call accuracy of Q30 for at least 80% of bases depending on application and sample quality.