Table 1.

Performance of whole genome sequencing in detection of repeat expansions

	Before visual inspection	After visual inspection
True negative	1316	1321
False positive	5	0
True positive	215	219
False negative	6	2
Specificity, % (95% CI)	99·6% (99·1–99·9)	100% (99·7–100)
Sensitivity, % (95% CI)	97·3% (94·2–99·0)	99·1% (96·8–99·9)
Positive predictive value, % (95% CI)	97·7% (94·7–99·0)	100%
Negative predictive value, % (95% CI)	99·6% (99·0–99·8)	99·9% (99·4–100)
Accuracy, % (95% CI)	99·3% (98·7–99·6)	100% (99·5–100)

Performance based on total number of non-expanded and expanded alleles across all loci tested before and after visual inspection.