Newborn Pulse Oximetry Screening: A Medical-Legal Guide for Attorneys

This article is for education only. It does not give legal advice and does not offer an opinion on liability in any specific case. Legal standards of care depend on the jurisdiction and the facts of each case.

Introduction

Newborn pulse oximetry screening is a quick, painless bedside test. It checks the oxygen level in a baby's blood before the baby goes home from the hospital. Its main goal is to find critical congenital heart disease (CCHD): heart defects that usually need surgery or catheter treatment in the first year of life and that can become life-threatening once the ductus arteriosus (a fetal blood vessel) closes in the first days after birth.

Because the screen happens in nearly every US birthing hospital, it often comes up in litigation over a congenital heart defect that was diagnosed late. Common questions include:

• Was the screen done?
• Was it done correctly and at the right time?
• Was the result read correctly?
• Was an abnormal result acted on quickly enough?
• If the baby passed, should the defect have been found some other way?

To answer these questions fairly, attorneys need to understand both what the screen does well and what it cannot do. A passed screen does not rule out heart disease, and a missed defect after a passed screen does not, by itself, show that care fell below the standard.

Clinical Vignette (Hypothetical)

This case is fictional and written for teaching purposes only.

A full-term baby boy is born by uncomplicated vaginal delivery. The mid-pregnancy anatomy ultrasound was reported as normal. At 26 hours of age, a nurse performs the CCHD screen. The documented values are 94% in the right hand and 93% in the foot. The nursing note says "within normal limits — passed." No retest is recorded. The baby is discharged at 36 hours.

On day 4, the parents call the pediatrician's office because the baby is breathing fast and feeding slowly. They are told this is common and to come in for the scheduled visit on day 5. At that visit, the baby looks dusky and his oxygen saturation is 78%. He is sent to the emergency department, started on prostaglandin E1, and transferred to a children's hospital. Echocardiography shows d-transposition of the great arteries. He has metabolic acidosis on arrival and needs urgent balloon atrial septostomy before surgery.

This case raises several issues an expert would review:

• Interpretation: Under the AAP algorithm, values of 90–94% call for a retest, not a pass. Recording "passed" with these numbers would be an interpretation error.
• Systems: Did the hospital train staff on the algorithm? Did the electronic record calculate the result automatically?
• After discharge: Was the phone triage of fast breathing and poor feeding reasonable?
• Causation: Would a retest an hour later have failed and led to diagnosis before discharge? How much of the baby's later injury, if any, comes from the delay rather than the defect itself?

Why Screen? The Medical Rationale

Many babies with CCHD look healthy at birth. While the ductus arteriosus stays open, it can keep enough blood flowing to the body or lungs to hide the problem. When it closes, usually within the first days to weeks, the baby can collapse suddenly, often at home.

Doctors and nurses cannot reliably see mild low oxygen. Cyanosis (a blue color) usually is not visible until oxygen saturation drops to about 80% or lower. It is even harder to see in babies with darker skin (American Society of Echocardiography; Wasserman et al., Journal of the American Society of Echocardiography, 2021). A pulse oximeter can detect much milder drops in oxygen that the eye would miss.

The screen mainly targets these defects:

• Primary targets (defects that usually cause low oxygen): hypoplastic left heart syndrome, pulmonary atresia, tetralogy of Fallot, d-transposition of the great arteries, tricuspid atresia, truncus arteriosus, and total anomalous pulmonary venous return.
• Secondary targets: coarctation of the aorta, interrupted aortic arch, Ebstein anomaly, double outlet right ventricle, and other single-ventricle hearts.

The screen detects the primary, low-oxygen defects best, with sensitivity above 90%. It detects coarctation worst, at about 36% (Donlon et al., Pediatric Cardiology, 2026).

History and Policy Background

• 2011: CCHD screening was added to the federal Recommended Uniform Screening Panel. The AAP, AHA, American College of Cardiology, and March of Dimes supported it (Mahle et al., Pediatrics, 2012; Schwartz et al., Pediatrics, 2021).
• By July 2018: All US states and territories had adopted CCHD screening (Oster et al., Pediatrics, 2025).
• 2020: An expert panel recommended two changes to the algorithm. A baby must have at least 95% in both the hand and the foot to pass (previously either), and only one retest is allowed instead of two (Martin et al., Pediatrics, 2020).
• 2025: The AAP clinical report formally adopted the new algorithm. It also stated that the baby should not be on supplemental oxygen during screening, and that families and clinicians need to understand that CCHD can still be present after a passed screen (Oster et al., Pediatrics, 2025).

Most states, 47 of 50, follow the AAP protocol, but the details vary by state (Ting et al., Pediatric Cardiology, 2026). In litigation, the algorithm in force at that hospital and in that state on the date of birth matters. A birth in 2016 would usually have been judged under the 2011 algorithm. A birth in 2024 might have been judged under either version, depending on when the state and hospital adopted the change.

Evidence of Benefit

In a JAMA study, early infant deaths from CCHD fell by 33% in states that required screening, compared with earlier years and with states without such rules (Abouk et al., JAMA, 2017). That is about 120 infant deaths prevented each year in the US (Donlon et al., 2026). Required screening has also been linked to fewer emergency hospital admissions for CCHD. Screening takes about 9 minutes per baby and costs about $14 (2011 dollars) (Oster et al., 2025).

How the Screen Is Performed

Under current AAP guidance (Oster et al., 2025; Martin et al., 2020):

1. Who is screened: Every newborn not already known to have CCHD. For example, a baby already diagnosed before birth or already evaluated by echocardiogram does not need the screen.
2. When: At or after 24 hours of age, or shortly before discharge if the baby leaves earlier. Screening before 24 hours produces more false alarms, because a newborn's oxygen level is still rising in the first day. The false-positive rate was 0.42% before 24 hours vs 0.06% after (Plana et al., Cochrane Database of Systematic Reviews, 2018).
3. Where on the body: The right hand, which shows oxygen in blood before the ductus (pre-ductal), and either foot, which shows blood after the ductus (post-ductal).
4. Conditions: The baby should be off supplemental oxygen. Accurate readings need a calm, warm baby and a steady signal.
5. Who performs it: Staff trained in pulse oximetry and in the algorithm.

The Current Algorithm (2020 panel; adopted by AAP 2025)

Source: Martin et al., Pediatrics, 2020; Oster et al., Pediatrics, 2025.

Under the older 2011 algorithm, a baby could pass with 95% or more in either site, and up to two retests were allowed. The 2020 panel noted that the "either" wording confused staff and led to misreadings (Martin et al., 2020).

How Accurate Is the Screen?

The best summary evidence is a Cochrane review of 21 studies with more than 450,000 newborns (Plana et al., 2018):

• Sensitivity: 76.3%. The screen detects about 3 of every 4 babies with CCHD. The certainty of this estimate is low because results varied widely between studies.
• Specificity: 99.9%. False positives are rare, about 0.14%.
• What this means in practice: Among 10,000 apparently healthy newborns, about 6 will have CCHD. The screen will find about 5 and miss about 1, and will falsely flag about 14 babies who do not have CCHD.

False Negatives (Missed Cases)

Some babies with CCHD will pass. This is an expected limit of the test, not necessarily a sign that it was done wrong. Common reasons:

• Defects without low oxygen. Coarctation and other blockages on the left side of the heart may cause little or no drop in oxygen while the ductus is open. Sensitivity for coarctation may be as low as 21% (Oster et al., 2025).
• Timing. Oxygen levels can be normal at 24 hours and drop later as the ductus closes.
• Technical factors. Movement, poor signal, a cold baby, or a probe in the wrong place.
• Supplemental oxygen during screening can hide low oxygen.
• Skin pigment. There are concerns that pulse oximeters may overestimate oxygen in people with darker skin. The AAP has called for more research on this (Oster et al., 2025).

False Positives

A "false positive" for CCHD is often not a false alarm. Babies who fail because of low oxygen are more likely to have a non-cardiac cause, such as sepsis, pneumonia, or persistent pulmonary hypertension of the newborn, than CCHD. These conditions also benefit from early treatment (Oster et al., 2025). A failed screen therefore calls for a medical evaluation, not just a heart check.

Medical Issues Commonly Reviewed by Experts

Experts often focus on the following questions. Whether any answer amounts to a breach of the legal standard of care is a question for the trier of fact under the governing law.

1. Was the screen done? Look for documented values, times, sites, and the recorded result. Valid reasons not to screen include a known prenatal diagnosis, an echocardiogram already done, or NICU care with continuous monitoring, depending on the protocol. Home births and birth-center births may have different processes. Modified screening schedules that fit midwifery practice have been studied (Williams et al., Pediatrics, 2021).

2. Was it done properly?

• Was the baby at least 24 hours old, or about to be discharged?
• Were both the right hand and a foot measured?
• Was the baby on room air?
• Was the equipment suitable for newborns?

3. Was it interpreted correctly? Compare the recorded numbers with the algorithm in force at the time. Common errors include recording "pass" for 90–94% readings, missing a hand–foot difference of 4% or more, or wrongly applying the "either" rule under the newer algorithm.

4. Was an abnormal result acted on? A fail calls for prompt evaluation by a physician, an echocardiogram (on site, by telemedicine, or by transfer), and a search for lung or infection causes (AAP, as summarized in Jullien, BMC Pediatrics, 2021). Delays between a failed screen and the echocardiogram, or discharging a baby with an unresolved retest, deserve careful review.

5. Communication and handoffs

• Did the result reach the discharging clinician and the outpatient pediatrician?
• Did the family get warning signs to watch for, such as fast breathing, poor feeding, color change, or sweating with feeds?

6. Systems issues

• Did the hospital have written protocols, staff training, and electronic tools that calculate the result automatically?
• Were results reported to the state? The AAP recommends better electronic record integration and linking screening data with birth defect registries to find missed cases (Oster et al., 2025).

7. Clinical judgment beyond the screen The CDC states that the screen should not replace a complete history and physical exam, which can sometimes find heart disease before oxygen drops (Jullien, 2021). Abnormal findings should be evaluated on their own merits whatever the screen showed, including:

• weak or absent femoral pulses
• a murmur
• fast breathing
• poor feeding
• a low oxygen reading at a later visit

Common Allegations in Litigation

Medical Causation

Showing that a screening error occurred is only part of the analysis. Experts also consider:

• Would correct screening have changed the timing of diagnosis? If a retest had been done properly, would it more likely than not have failed? Some babies with CCHD have normal oxygen at 24 hours.
• What lesion is involved? For defects without low oxygen, such as coarctation, a perfectly performed screen often would have passed.
• When did injury occur? Low oxygen, shock, and acidosis can damage the brain, kidneys, intestines, and heart. Injury may begin with ductal closure, which can happen before or after discharge. Records showing the baby's condition over time, including lactate, blood gases, organ-function tests, and brain imaging, help establish timing.
• What injury comes from the defect itself? Babies with CCHD have a higher baseline risk of developmental problems, and genetic syndromes, prematurity, surgical complications, and brain differences present before birth all contribute. Separating these from injury caused by delay requires careful, case-specific analysis.
• Probability vs possibility. Experts must usually state whether a different outcome was more likely than not, not just possible.

Population evidence shows that screening reduces deaths (Abouk et al., 2017). Population-level benefit does not, by itself, prove that earlier diagnosis would have changed the outcome for a particular child. Evidence on how screening affects illness severity at presentation and hospital stay is still developing (Ting et al., 2026).

Medical Records That Often Matter

• Prenatal ultrasound reports and images; any fetal echocardiogram
• Nursery flowsheets with raw saturation values, times, sites, and the recorded result
• Device logs, the hospital CCHD protocol, and staff training records in effect on the date of birth
• The state newborn screening report
• Physician newborn exams and discharge summary (pulses, murmur, breathing rate)
• Discharge instructions and family education records
• Outpatient visits, phone triage notes, and after-hours call logs
• Emergency department, transport, and NICU/cardiac ICU records
• Echocardiograms, catheterization and operative reports
• Brain imaging and long-term developmental follow-up

Common Misconceptions

• "A passed screen means the heart is normal." The screen misses about 1 in 4 cases of CCHD overall, and many more cases of coarctation (Plana et al., 2018; Oster et al., 2025).
• "Any missed CCHD after screening means the screen was done wrong." False negatives happen even with correct technique and interpretation.
• "A failed screen means heart disease." Many failures come from infection, lung disease, or pulmonary hypertension (Oster et al., 2025).
• "The screen replaces the physical exam." Professional guidance says it supplements, not replaces, the history and exam (Jullien, 2021).
• "Every delay in diagnosis changes the outcome." Whether delay caused harm depends on the lesion, timing, the baby's condition, and the course of the illness.

The Value of Pediatric Cardiology Expertise

Reviewing these cases requires knowledge of:

• newborn transitional circulation and how the ductus closes
• which defects the screen detects well and which it detects poorly
• how the screening algorithm has changed and how states adopted it
• echocardiography and the urgency of treatments such as prostaglandin and balloon septostomy
• the developmental outcomes of children with CCHD, so that injury from delay can be separated from risks of the defect itself

Key Takeaways for Attorneys

1. CCHD pulse oximetry screening has been universal in US states and territories since 2018.
2. The current algorithm requires 95% or higher in both the right hand and foot, a difference of 3% or less, and allows only one retest. Older algorithms differed.
3. Use the algorithm and hospital protocol in force on the date of birth.
4. Sensitivity is about 76% and specificity about 99.9%. A passed screen does not rule out CCHD.
5. The screen works best for defects that lower oxygen and is weak for coarctation and other left-sided blockages.
6. Many failed screens reflect infection or lung disease. These babies also need prompt evaluation.
7. Interpretation errors, especially calling 90–94% a "pass," and delays after a failed screen are frequent areas of review.
8. The screen does not replace the history, physical exam, and response to symptoms after discharge.
9. Causation requires showing that correct screening would more likely than not have led to an earlier diagnosis and a better outcome.
10. Raw values, device logs, protocols, and communication records are often decisive.

References

• Mahle et al. Pediatrics, 2012.
• Schwartz et al. Pediatrics, 2021.
• Martin et al. Pediatrics, 2020.
• Oster et al. Pediatrics, 2025.
• Wasserman et al. Journal of the American Society of Echocardiography, 2021.
• Donlon et al. Pediatric Cardiology, 2026.
• Ting et al. Pediatric Cardiology, 2026.
• Abouk et al. JAMA, 2017.
• Plana et al. Cochrane Database of Systematic Reviews, 2018.
• Williams et al. Pediatrics, 2021.
• Jullien. BMC Pediatrics, 2021.