Bilirubin (Newborn): Nursing Guide
Newborn bilirubin testing — total serum bilirubin (TSB) and transcutaneous bilirubin (TcB) — drives phototherapy, repeat testing, and discharge follow-up for infants 35 weeks or more gestation. Nurses prevent kernicterus by screening at 24–48 hours (or before earlier discharge), plotting results on hour-specific nomograms, confirming TcB with TSB when thresholds are approached, and escalating rising values with neurotoxicity risk factors.
Contents
Quick Facts
Key Takeaway
The main nursing priority with newborn bilirubin is age-in-hours interpretation on a validated nomogram — not a single “normal” number.
Specimen & Collection Details
Nurse quick-reference for collection prep that affects result quality.
Turnaround and screening rules vary by institution; follow local institutional policy
Verify local microtainer or serum tube requirements for TSB; protect specimen from light per laboratory policy
Capillary or venous blood (total serum bilirubin); transcutaneous bilirubin (TcB) at bedside
Small-volume capillary or venous sample per institutional neonatal phlebotomy protocol
Universal TcB or TSB between 24 and 48 hours after birth, or before discharge if earlier; sooner if jaundice is visible in the first 24 hours per AAP 2022 guidance
No special preparation is usually required, but nurses should follow local policy and the ordering clinician’s instructions
Label with date, time, and age in hours; transport TSB promptly; protect from light and hemolysis per laboratory policy
TcB: immediate; TSB: varies by site — often hours; STAT when exchange transfusion threshold is approached per protocol
Neonatal clinical chemistry / nursery point-of-care bilirubin
What is Bilirubin (Newborn)?
Bilirubin (Newborn) measures bilirubin in newborn infants to detect and manage hyperbilirubinemia. Total serum bilirubin (TSB) is a laboratory blood test that quantifies circulating bilirubin and is used to guide phototherapy and escalation decisions. Transcutaneous bilirubin (TcB) is a non-invasive bedside measurement of skin bilirubin that can reduce blood draws when used as a screening test linked to confirmatory TSB per guideline protocols.
Overview
Nurses in well-baby nurseries, postpartum units, and pediatric clinics use bilirubin testing to identify infants whose jaundice may progress to hazardous levels. The 2022 American Academy of Pediatrics (AAP) clinical practice guideline for infants 35 or more weeks’ gestation recommends visual jaundice assessment at least every 12 hours until discharge and objective measurement of TcB or TSB for all infants between 24 and 48 hours of age — or before discharge if that occurs earlier.
standard clinical references and national clinical guidelines emphasize that jaundice is common in newborns but can rarely lead to serious brain injury when follow-up is missed. Nurses support safe care by documenting age in hours at draw, gestational age, feeding pattern, hemolysis risk, and neurotoxicity risk factors alongside each result.
Before measurement, confirm gestational age, exact age in hours since birth, feeding and weight change, visible jaundice zone using jaundice assessment, and risk factors such as early jaundice, bruising, exclusive breastfeeding with inadequate intake, or isoimmune hemolysis concern. After results, plot TSB on the hour-specific nomogram used by your unit, obtain confirmatory TSB when TcB is within 3 mg/dL of the phototherapy threshold or ≥15 mg/dL per AAP recommendations, and order or follow up direct antiglobulin (DAT) testing when hemolysis is suspected per protocol.
Kernicterus Prevention and Bilirubin Escalation Safety
Most newborn jaundice resolves safely, but hazardous hyperbilirubinemia remains preventable when nurses measure bilirubin at the right age, plot results on hour-specific nomograms, confirm TcB with TSB when guidelines require it, and ensure follow-up after predischarge screening. Missing a high-risk zone on the nomogram is a common systems failure — not just a laboratory issue.
- TSB approaching exchange transfusion threshold or acute bilirubin encephalopathy signs
- Jaundice visible in the first 24 hours without prompt bilirubin measurement and workup
- Discharge without follow-up after predischarge bilirubin in high-risk or phototherapy zone
- Treating TcB alone when confirmatory TSB is required before phototherapy decisions
Document: gestational age, age in hours at draw, TSB/TcB values, nomogram zone, feeding and weight data, risk factors, prescriber notification, phototherapy orders, repeat bilirubin schedule, and outpatient follow-up plan.
What Newborn Bilirubin Can and Cannot Tell You
This test can help identify:
- Degree of hyperbilirubinemia when interpreted with age in hours on a nomogram
- Need for phototherapy, repeat testing interval, or higher level of care per AAP thresholds
- Response to phototherapy when serial TSB values are trended
- Need for hemolysis workup when paired with early jaundice, DAT, or rapid rise
This test cannot:
- Diagnose the exact cause of jaundice without clinical context and adjunct tests
- Replace visual jaundice assessment every 12 hours until discharge
- Use a single adult reference interval — thresholds are age-in-hours and risk-adjusted
- Rule out kernicterus risk when follow-up after a high-risk predischarge screen is missed
Pre-measurement Checks for TSB and TcB
Verify
Clarify before proceeding when:
- Age in hours is uncertain — confirm birth time before plotting nomogram
- Jaundice appears within first 24 hours — expedite TSB and prescriber review
- TcB is high but confirmatory TSB not yet ordered when protocol requires it
- Infant near discharge without predischarge bilirubin between 24–48 hours
- Phototherapy recently stopped — clarify repeat TSB timing for rebound
- Parent cannot keep follow-up — escalate care coordination before discharge
- Neurologic signs (lethargy, poor suck, arching) conflict with “mild” jaundice appearance
Reading Bilirubin With Age-in-Hours and Nomograms
Plot every TSB on the hour-specific nomogram your unit uses (often derived from Bhutani curves and updated AAP phototherapy tools). Integrate results with gestational age, neurotoxicity risk factors, feeding, weight trend, DAT, and serial values — one isolated result is insufficient for discharge planning.
| Clinical context | Pair with bilirubin | Nursing focus |
|---|---|---|
| Term infant, 36 h, exclusive breastfeeding | TSB near phototherapy line; 8% weight loss | Notify prescriber; support feeding; repeat TSB per nomogram; teach follow-up |
| Jaundice at 18 h | TSB rising; DAT positive concern | Expedite hemolysis labs; escalate per protocol; do not delay for routine timing |
| On phototherapy | TSB trend every 4–12 h per orders | Eye protection, thermoregulation, skin contact when safe; evaluate rebound after stop |
| Predischarge screen | High-intermediate or high zone on nomogram | Schedule outpatient TSB within guideline interval; document teach-back |
Reference ranges and critical values may vary by laboratory, institution, analyzer, age, sex, pregnancy status, and clinical context. Always interpret results using the reporting laboratory’s reference range and local escalation policy.
TcB, Heelstick, and Feeding at the Nursery Bedside
| Bedside point | Nursing note |
|---|---|
| Hours matter | Always chart age in hours — a “15 mg/dL” value means different actions at 24 h vs 72 h |
| TcB → TSB rule | Know your unit’s AAP-based cutoff for confirmatory TSB — NCLEX and real nurseries test this |
| Feeding link | Poor intake and weight loss amplify risk — coordinate lactation support while treating bilirubin |
| Light protection | Protect TSB tubes from light per lab policy to avoid specimen degradation |
| Follow-up trap | High-intermediate nomogram zone needs a timed outpatient TSB — verify appointment before sign-out |
| Early jaundice | Face-only jaundice at 12 h is different from abdomen at 48 h — measure, do not wait |
Universal Screening and Phototherapy Workflow
Diagnostic safety badge: Critical-result test — prompt review and escalation may be required when phototherapy or exchange thresholds are approached.
Check-before-test protocol
- Identity + GA + age in hours
- Visual jaundice zone and feeding/weight assessment
- TcB or TSB per screening window (24–48 h)
- Plot on nomogram; confirm TSB when indicated
- Follow-up appointment and parent teach-back before discharge
Critical teach-back questions
- “Can you tell me why we checked your baby’s bilirubin level today?”
- “What changes in feeding, skin color, or alertness should you report right away?”
- “When and where is your follow-up bilirubin or pediatric appointment?”
Care coordination: pediatrician, neonatology, lactation, laboratory, outpatient clinic, and social work when follow-up barriers exist — per institutional protocol.
Newborn Bilirubin Quick Safety Checklist
- What is this infant’s exact age in hours and gestational age?
- Was predischarge bilirubin measured between 24–48 hours (or before earlier discharge)?
- Does TSB require confirmation because TcB crossed protocol thresholds?
- Are feeding, weight loss, or DAT results changing the risk profile?
- Is outpatient follow-up scheduled and understood before discharge?
Why Bilirubin (Newborn) is Ordered
Newborn bilirubin is ordered to screen for hyperbilirubinemia, determine treatment thresholds, and plan safe discharge follow-up.
| Clinical Indication | What the Test Answers | Nursing Rationale |
|---|---|---|
| Universal predischarge screening (24–48 hours or before earlier discharge) | Does this infant need measured bilirubin before leaving the birth facility? | AAP recommends TcB or TSB for all infants in this window to link results to follow-up and reduce hazardous hyperbilirubinemia after discharge. |
| Visible jaundice in the first 24 hours after birth | Is jaundice appearing earlier than expected physiologic timing? | Early jaundice increases concern for hemolysis or pathologic causes — measure bilirubin promptly and expand workup as ordered. |
| Monitoring response to phototherapy or home phototherapy | Is bilirubin falling appropriately on therapy, or is rebound testing needed? | Serial TSB trends guide continued phototherapy, supplemental feeding, and readmission decisions per nomogram and prescriber orders. |
| Follow-up after nursery discharge with ongoing jaundice | Has outpatient jaundice worsened since predischarge screening? | Repeat TSB with age in hours supports timely re-initiation of phototherapy and prevention of readmission delays. |
Contraindications and Precautions
Bilirubin measurement has few true contraindications. Capillary heelstick and venipuncture require standard newborn blood-draw precautions; TcB may be unreliable on certain skin surfaces or after phototherapy unless device protocol allows remeasurement.
- TSB at or approaching exchange transfusion threshold for gestational age and risk profile — notify neonatology and initiate intensive phototherapy per protocol
- Jaundice in the first 24 hours, rapidly rising bilirubin, or clinical signs of acute bilirubin encephalopathy (lethargy, poor tone, high-pitched cry, arching)
- Missed follow-up after predischarge bilirubin in high-risk zone on nomogram — escalate care coordination immediately
- TcB does not replace TSB for treatment decisions when TcB is ≥15 mg/dL or within 3 mg/dL of the phototherapy threshold per AAP 2022 guidance
- Phototherapy, skin color, birth trauma, and device calibration can affect TcB — follow manufacturer and institutional validation policy
- Do not compare results without documenting exact age in hours and gestational age on the nomogram used by your facility
- TSB crossing phototherapy threshold for infant’s risk category on hour-specific nomogram
- Neurotoxicity risk factors present (e.g., gestational age under 38 weeks, isoimmune hemolysis, sepsis, albumin below 3.0 g/dL per AAP) with rising bilirubin
- Parent reports worsening jaundice, poor feeding, or decreased alertness after discharge
Patient Preparation
Most newborns need no fasting preparation. Focus on accurate timing, risk-factor documentation, and parent education about follow-up.
Pre-test checksReview medicines given to infant or birthing parent that may affect bilirubin (e.g., sulfonamides in infant newborn jaundice information). Document exclusive breastfeeding, supplementation, and any phototherapy already in progress. Do not withhold feeding unless specifically ordered.
Performance — nursing procedure guide
This page is a Tests & Diagnostics guide for Bilirubin (Newborn). It emphasizes why the test is ordered, how to interpret results, when to escalate, and preparation factors that affect validity — not step-by-step performance technique (those live under Nursing Procedures when available).
Step-by-step technique, supplies, infection prevention, and immediate post-procedure monitoring for this test are covered in:
Use the Patient preparation, Results and interpretation, and Nursing responsibilities sections on this page for order verification, pre-analytic checks, result follow-up, critical-value escalation, and documentation.
Result follow-up at a glance
Nursing workflow on this page — from order to safe action on results:
Results and Interpretation
TSB is reported in mg/dL or µmol/L using the reporting laboratory’s units. Interpret each value using age in hours on the nomogram and phototherapy/exchange thresholds adopted by your institution from current guideline tools — not a single static reference interval.
Reference ranges, critical values, and protocols may vary by laboratory, institution, patient population, and testing method. Always follow local policy and the reporting laboratory’s reference range.
| Result | Range / Finding | Clinical Meaning | Nursing Action |
|---|---|---|---|
| Within reference interval | Age-in-hours specific on Bhutani-style nomograms — institution and guideline dependent | Bilirubin below phototherapy threshold for documented age in hours and risk category | Continue routine visual monitoring and scheduled follow-up per predischarge plan |
| Borderline / near reference limit | Approaching phototherapy threshold on nomogram for age in hours | May require repeat TSB within guideline-defined interval or enhanced feeding support | Notify prescriber; repeat bilirubin per nomogram; reinforce feeding and follow-up teaching |
| High / above reference interval | At or above phototherapy threshold for age, GA, and risk factors | Hyperbilirubinemia requiring phototherapy or higher level of care per AAP thresholds | Initiate phototherapy per order; repeat TSB per protocol; monitor feeding and neurologic status |
| Low / below reference interval | Not applicable for isolated low TSB in screening context | Low values are not the primary clinical concern — focus on trend and threshold crossing | Continue screening schedule; do not defer follow-up because current value is low |
Critical Results and Escalation
Numeric institution-wide critical TSB values are Turnaround and screening rules vary by institution; follow local institutional policy. Escalation uses gestational-age and risk-adjusted phototherapy and exchange transfusion thresholds on hour-specific nomograms per AAP 2022 guidance.
| Critical Finding | Threshold / Value | Immediate Action |
|---|---|---|
| TSB at exchange transfusion threshold | At or within approximately 2 mg/dL of exchange threshold for age and risk profile per institutional nomogram | STAT repeat TSB, intensive phototherapy, neonatology notification, prepare for exchange transfusion workup per protocol |
| Rapid rate of bilirubin rise | Rate of rise concerning for hemolysis per prescriber assessment (e.g., >0.3 mg/dL/h in first 24 hours or >0.2 mg/dL/h thereafter when clinically indicated) | Expand workup (CBC, DAT, reticulocyte count as ordered); escalate according to facility policy |
| Acute bilirubin encephalopathy signs | Lethargy, poor suck, hypotonia or hypertonia, high-pitched cry with elevated TSB | Activate local emergency response according to institutional protocol; urgent neonatology evaluation |
Escalate according to facility policy and the patient’s clinical condition when TSB approaches exchange threshold, when jaundice appears in the first 24 hours, when feeding or neurologic status deteriorates, or when outpatient follow-up is missed after a high-risk predischarge result.
Factors Affecting Results
Newborn bilirubin interpretation depends on age in hours, gestational age, feeding, hemolysis risk, assay method, and specimen quality.
- TcB overestimation on bruised skin, birth trauma sites, or darker skin tones without confirmatory TSB when treatment is considered
- Single TSB without plotted age in hours appearing “high” on adult reference ranges
- Assuming all jaundice is benign physiologic jaundice without timing and risk assessment
- Reassurance based on TcB alone when confirmatory TSB was required by protocol
- Normal predischarge value without scheduled follow-up when infant was in high-risk zone
- Missing jaundice below the visual threshold while bilirubin is rising toward phototherapy level
- Age in hours not documented — invalid nomogram comparison
- Hemolysis, lipemia, or light exposure of TSB specimen
- Recent phototherapy affecting TcB; exclusive breastfeeding with inadequate intake
TcB is a screening tool and does not replace TSB for treatment decisions when thresholds are approached per AAP guidance. Bilirubin level alone does not identify every cause of jaundice — hemolysis, sepsis, and biliary disorders may require CBC, DAT, and fractionated bilirubin. Always interpret with gestational age, feeding, exam, and trend.
Nursing Responsibilities
Nursing care spans visual screening, accurate TSB/TcB measurement, nomogram plotting, phototherapy support, parent teaching, and postdischarge follow-up coordination.
Before the TestDocumentation
Clear documentation supports safe handoff between nursery, laboratory, and outpatient follow-up.
“41-hour-old, 38w2d GA. TcB 14.8 mg/dL sternum; confirmatory TSB 15.6 mg/dL at 1142. Plotted on unit nomogram — above phototherapy threshold for age. Exclusive breastfeeding; 8% below birth weight. DAT pending. Dr. Patel notified; double phototherapy ordered. Repeat TSB in 4–6 h per protocol. Parent taught jaundice follow-up and poor feeding signs.”
- Gestational age and exact age in hours at measurement
- TSB and/or TcB values with units and nomogram zone
- Feeding method, weight change, jaundice zone, and risk factors
- Phototherapy orders, eye protection, and repeat bilirubin schedule
- Prescriber notification and discharge follow-up appointment
- Parent teaching on worsening jaundice and neurologic warning signs
Patient and Family Education
Teach parents using plain language while emphasizing follow-up timing.
Bilirubin (Newborn) NCLEX practice questions
Practice NCLEX-style clinical judgment focused on Bilirubin (Newborn) safety and nursing judgment. Use the case tabs (orders, results, assessment, nursing notes), then answer eight Next Gen–style items (including an ordered workflow step) and evaluate outcomes with the answer key.
Select a tab to view orders, results, assessment, and nursing note details for this case.
- Order: Universal bilirubin screening — term newborn nursery
- Indication: 40-hour-old infant; predischarge TcB/TSB per nursery protocol
- Timing: Born 38w4d; now 40 hours of age; screening due before discharge planning
- Related orders: TcB now; TSB if threshold approached; DAT and CBC if hemolysis concern; repeat TSB per nomogram
- Result: TcB 14.6 mg/dL (sternum); confirmatory TSB 15.4 mg/dL at 40 h life
- Trend / prior value: Above phototherapy threshold for age on unit nomogram; no prior TSB
- Pending tests: Maternal type O/Rh+; infant type A/Rh+; DAT result pending
- Vital signs: T 36.8°C, HR 138/min, RR 44/min, SpO₂ 98% room air
- Symptoms: Jaundice to abdomen; active suck but feeds every 3–4 h; 7% below birth weight
- Focused assessment: Alert, good tone, soft abdomen; not yet on phototherapy
- Preparation notes: TcB device calibrated this shift; parents anxious about heelstick
- Collection events: TSB heelstick 1030 — one attempt; specimen sent STAT
- Teaching gaps / safety concerns: TSB above phototherapy line with exclusive breastfeeding and weight loss; DAT pending; follow-up appointment not yet scheduled
Answer key & rationale
Frequently Asked Questions
FAQ
When should newborn bilirubin be measured?
The 2022 AAP guideline recommends measuring TcB or TSB for all infants 35 weeks or more gestation between 24 and 48 hours after birth, or before discharge if earlier, and sooner if jaundice appears in the first 24 hours.
Is TcB the same as TSB?
No. TcB is a non-invasive screening measurement. TSB is the definitive blood test for treatment decisions. AAP guidance recommends TSB when TcB is ≥15 mg/dL or within 3 mg/dL of the phototherapy threshold.
What does a high TSB mean in a newborn?
It indicates hyperbilirubinemia — bilirubin high enough to require plotting on an age-in-hours nomogram and may require phototherapy, enhanced feeding, or further testing for hemolysis depending on threshold and risk factors.
Does breastfeeding cause dangerous jaundice?
breastfeeding jaundice can occur with inadequate intake in the first week. Nurses monitor feeding, weight, and bilirubin trends and support lactation while escalating when thresholds are crossed — not assuming all breastfed jaundice is benign.
When should nurses escalate newborn bilirubin results?
Escalate when TSB crosses phototherapy or exchange thresholds on the nomogram, when jaundice is early or rising rapidly, when neurologic signs appear, or when follow-up after a high-risk screen is missed — according to facility policy.
What risk factors lower the phototherapy threshold?
AAP neurotoxicity risk factors include gestational age under 38 weeks, albumin below 3.0 g/dL, isoimmune hemolytic disease, G6PD deficiency, sepsis, and significant clinical instability — thresholds are lower when any are present.
What related tests may accompany bilirubin screening?
When hemolysis or severe jaundice is suspected, clinicians may order CBC, direct antiglobulin test (DAT), reticulocyte count, and fractionated bilirubin — nurses coordinate collection per orders.
References
References
-
Kemper AR; Newman TB; Slaughter JL; et al. Clinical Practice Guideline Revision: Management of Hyperbilirubinemia in the Newborn Infant 35 or More Weeks of Gestation. Pediatrics. 2022;150(3):e2022058859.https://doi.org/10.1542/peds.2022-058859
-
U.S. National Library of Medicine. Jaundice in Newborns. MedlinePlus.https://medlineplus.gov/ency/article/001472.htm
-
National Institute for Health and Care Excellence. Jaundice in newborn babies under 28 days. NICE guideline NG98.https://www.nice.org.uk/guidance/ng98
-
Kaplan M; Wong RJ; Burgis JC; et al. Neonatal Jaundice and Breastfeeding. Pediatrics. 2023;151(6):e2023060627.https://doi.org/10.1542/peds.2023-060627
-
Bhutani VK; Johnson L; Sivieri EM. Predictive Ability of a Predischarge Hour-Specific Serum Bilirubin for Subsequent Significant Hyperbilirubinemia in Healthy Term and Near-Term Newborns. Pediatrics. 1999;103(1):6–14.https://doi.org/10.1542/peds.103.1.6
-
American Academy of Pediatrics. Hyperbilirubinemia and jaundice in the newborn infant 35 or more weeks of gestation. HealthyChildren.org.https://www.healthychildren.org/English/news/Pages/AAP-revises-clinical-guidelines-for-hyperbilirubinemia-in-newborns.aspx
-
Maisels MJ; Bhutani VK; Bogen D; et al. Hyperbilirubinemia in the Newborn Infant ≥35 Weeks’ Gestation: An Update With Clarifications. Pediatrics. 2009;124(4):1193–1198.https://doi.org/10.1542/peds.2009-0329
-
Neiger R. Neonatal Hyperbilirubinemia. StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024.https://www.ncbi.nlm.nih.gov/books/NBK470302/
Editorial Standards & Medical Review
About the author: Sid A. Abdala Balal, RN, writes evidence-based nursing education focused on diagnostic safety, clinical interpretation, and bedside nursing judgment.
Medical review: This guide is reviewed by Dr. Adam Sayedi, MD, for clinical accuracy, diagnostic safety, and alignment with current standards for Bilirubin (Newborn).
Policies: Medical Review Process · Editorial Policy · Correction Policy