Two cases of placental trisomy 21 mosaicism causing false-negative NIPT results

Table 1 NIPT results for cases 1 and 2

Patient	Gestational Weeks	Unique reads/M	Fetal DNA Fraction (%)	NIPT Z-scores			NIPT result
Patient	Gestational Weeks	Unique reads/M	Fetal DNA Fraction (%)	Chromosome13	Chromosome18	Chromosome21	NIPT result
Case 1	15^a	3.79	15.67	− 0.001	0.906	− 0.201	Low risk
	15^b	8.54	14.89	− 0.432	− 0.01	0.951	Low risk
	29^c	5.62	20.30	0.52	0.249	1.219	Low risk
	15^d	9.86	20.10	− 1.22	0.93	0.566	Low risk
	29^e	9.85	17.90	0.606	− 0.731	3.414	Critical risk of T21
Case 2	17	3.90	19.70	1.527	0.466	0.932	Low risk

Bold font indicates a high risk NIPT result
Z scores were calculated as previously described [18] with a normal range > − 3 and < 3
a The Clinical laboratory data from the first examination
b The Clinical laboratory data from the reexamination
c The Clinical laboratory data before labor induction
d The third-party data from the first examination
e The third-party data before labor induction

ISSN: 1755-8166