Item	Criteria for assessment
Domain 1: Patient selection
Describe methods of patient selection (prior testing, presentation, intended use of index test and setting).
A. Risk of bias
Was a consecutive or random sample of patients enrolled?	"Yes" if described enrolling a consecutive or random sample of newborns before discharge from hospital "No" if criteria for "yes" not achieved "Unclear" if the study did not describe the method of enrollment
Did the study avoid inappropriate exclusions?	"Yes" if exclusions were detailed and review authors reached consensus on the appropriateness of any exclusion "No" if inappropriate exclusions were reported (eg, if cases with antenatally diagnosed congenital heart disease were excluded) "Unclear" if insufficient information was provided
Could selection of patients have introduced bias?	A judgment of low, high, or unclear risk of bias was based on a balanced assessment of responses to the above signaling questions.
B. Concerns about applicability
Is there concern that the included patients do not match the review question?	A judgment of low, high, or unclear concern about applicability was made on the basis of how closely the sample matches an asymptomatic newborn population screened for CCHD.
Domain 2: Index test
Describe the index test and how it was conducted and interpreted.
A. Risk of bias
Were the index test results interpreted without knowledge of results of the reference standard?	"Yes" if pulse oximetry was conducted and interpreted before the echocardiogram or clear temporal pattern to the order of testing that precludes the need for formal blinding (eg, echocardiogram, clinical follow‐up, and inclusion in congenital anomaly registries are always posterior to index test) "No" if reference standard results were available to those who conducted or interpreted the pulse oximetry "Unclear" if insufficient information was provided
If a threshold was used, was it prespecified?	"Yes" if a threshold was prespecified "No" if trial authors selected a cutoff value based on analysis of collected data "Unclear" if insufficient information was provided
Could the conduct or interpretation of the index test have introduced bias?	A judgment of low, high, or unclear risk of bias was based on a balanced assessment of responses to the above signaling questions.
B. Concerns about applicability
Is there concern that the index test, its conduct, or its interpretation differ from the review question?	A judgment of low, high, or unclear concern about applicability was based on a balanced assessment of information detailed under "index test" description.
Domain 3: Reference standard
Describe the reference standard(s) and how they were conducted and interpreted.
A. Risk of bias
Is the reference standard likely to correctly classify the target condition?	"Yes" if the study used an appropriate reference standard (diagnostic echocardiography and clinical follow‐up in the first 28 days of life, including postmortem findings and mortality and congenital anomaly databases to identify false‐negative patients) "No" if the study did not use an appropriate reference standard "Unclear" if the reference standard used was not clearly specified
Were the reference standard results interpreted without knowledge of results of the index test?	"Yes" if the person undertaking the reference test did not know the results of the pulse oximetry "No" if pulse oximetry results were available to those who conducted or interpreted the echocardiogram "Unclear" if insufficient information was provided
Could the reference standard, its conduct, or its interpretation have introduced bias?	A judgment of low, high, or unclear risk of bias was based on a balanced assessment of responses to the above signaling questions.
B. Concerns about applicability
Is there concern that the target condition as defined by the reference standard does not match the question?	A judgment of low, high, or unclear concern about applicability was based on the possibility of reference standards mixing both critical and non‐critical congenital heart disease.
Domain 4: Flow and timing
Describe any patients who did not receive the index test and/or reference standard(s) or who were excluded from the two‐by‐two table (refer to flow diagram), and describe the time interval and any interventions between index test and reference standard(s).
A. Risk of bias
Was at least 28 days of appropriate follow‐up provided?	"Yes" if follow‐up was at least 28 days "No" if follow‐up was less than 28 days "Unclear" if insufficient information was provided
Did all patients receive a reference standard?	"Yes" if the study specifically stated that all patients received echocardiogram, clinical follow‐up, or confirmation by mortality and congenital anomaly databases (for both positive and negative pulse oximetry results) "No" if some negative pulse oximetry participants were lost to follow‐up without any confirmation "Unclear" if insufficient information was provided
Were all patients included in the analysis?	"Yes" if the study had no withdrawals or withdrawals were clearly described "No" if the number of patients contributing to the two‐by‐two tables did not match the number of patients recruited and no reasons for exclusions were described "Unclear" if information was not enough to establish the flow of participants
Could the patient flow have introduced bias?	A judgment of low, high, or unclear risk of bias was based on a balanced assessment of responses to the above signaling questions.