Sparks 2012a.

Study characteristics
Patient sampling	Study design: case‐control study from a prospective cohort. Participants: pregnant women selected from a high risk of fetal aneuploidy population. Inclusion criteria: women at least 18 years of age, at least 10 weeks’ gestation and have singleton pregnancy. Exclusion criteria: multifetal pregnancies.
Patient characteristics and setting	Number enrolled: not reported. A subset of 338 pregnant women including 171 women in the training set (data not shown in the present review) and 167 women in the validation set were selected for this study. Number available for 2 x 2 table: 167 pregnant women (subgroup of 49%). Setting: not reported. Recruitment period: not reported. Ethnicity: not reported. Mean gestational age (± SD; range): 18.6 (± 4.0; 11 to 36.1) weeks. Mean maternal age (± SD; range): 33.5 (± 7.1; 18 to 51) years. Relevant tests carried out prior to index test: not reported. Language of the study: English.
Index tests	gNIPT by TMPS (DANSR assay) on Illumina HiSeq 2000 sequencer in multiplex with FORTE algorithm. Range fetal fraction DNA: 3% to 33%. It is not reported if the blood samples for gNIPT were collected before or after reference standard. Cutpoint: not reported. Commercial test: Ariosa Diagnostics, Inc's prenatal test.
Target condition and reference standard(s)	Target conditions: T21 and T18. Reference standards: fetal karyotype or chromosome analysis by FISH or both.
Flow and timing	It is not reported if the blood samples were collected before or after invasive procedure (reference standard). gNIPT was a second‐tier test. 171/338 samples were excluded for the training set. No failed sample reported in the validation set. No repeated test reported.
Comparative
Aim to study	To develop a novel biochemical assay and algorithm for the prenatal evaluation of risk for fetal T21 and T18 using ccfDNA obtained from maternal blood.
Funding source or sponsor of the study	Study funded by Ariosa Diagnostics, Inc. All authors are employees of Aria Dx Inc. (now Ariosa Diagnostics). K Sparks is a member of the board of the company.
Informations about the authors contacted	Author was contacted on: 23 June 2016. No reply received from the author.
Notes
Methodological quality
Item	Authors' judgement	Risk of bias	Applicability concerns
DOMAIN 1: Patient Selection
Was a consecutive or random sample of patients enrolled?	No
Was a case‐control design avoided?	No
Did the study avoid inappropriate exclusions?	No
		High	Low
DOMAIN 2: Index Test TMPS
Were the index test results interpreted without knowledge of the results of the reference standard?	Yes
If a threshold was used, was it pre‐specified?	Unclear
		Unclear	Low
DOMAIN 3: Reference Standard
Is the reference standards likely to correctly classify the target condition?	Yes
Were the reference standard results interpreted without knowledge of the results of the index tests?	Yes
		Low	Low
DOMAIN 4: Flow and Timing
Was there an appropriate interval between index test and reference standard?	Unclear
Did all analysed patients receive the reference standard?	Yes
Were all patients included in the analysis?	Yes
		Unclear