Neonatal%20jaundice Diagnosis

• Jaundice that appears in a newborn <24 hour old is most likely nonphysiologic and needs further evaluation
  • Visible jaundice of the feet may be an indication to check bilirubin level

• Visual estimation of bilirubin level is often inaccurate and unreliable

• Bilirubin levels should be plotted against nomogram appropriate for age of gestation and weight

Transcutaneous Bilirubinometry (TcB)

• A noninvasive way to measure serum bilirubin using handheld devices
• May be used as an initial screening test to detect possible development of hyperbilirubinemia
• Said to be equivalent to total serum bilirubin and may decrease the need for more invasive TSB measurements; however, more studies may be needed to validate tests that measure TcB

Total Serum Bilirubin (TSB)

• Measured if jaundice appears excessive for an infant’s age, when TcB level is >200 µmol/L (12 mg/dL), or if there is any doubt about the degree of jaundice
• Often the only test needed for infants who present with moderate jaundice on the 2nd or 3rd day of life and who do not have features suggesting pathologic jaundice

Laboratory Tests for Determining Cause of Jaundice

• Lab tests that will be requested will depend on the indications found in an infant
• Hematology: Hemoglobin and hematocrit, direct Coomb’s test, peripheral blood film, reticulocyte count, blood type and Rh determination in infant and mother
• Screening for G6PD deficiency in infants from high-risk populations
• Total and conjugated bilirubin to identify cholestasis
• Liver function tests: alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), alkaline phosphatase
  • A GGT/ALT ratio >2 is highly suggestive of biliary atresia

• Sepsis evaluation in infants who appear ill
  • Urinalysis, urine culture
  • Tests for parasitic and viral infections

• Measurement of end tidal carbon dioxide in breath as an index of bilirubin production
• Serum albumin to help evaluate risk of bilirubin toxicity
• Thyroid function tests

Imaging of the Liver and Biliary Tract

• Ultrasonography
  • Used for screening for biliary obstruction
  • Early screening for biliary atresia is important as prognosis worsens with later detection
• Radionuclide imaging
• Cholangiography
• Magnetic resonance cholangiopancreatography

Clinical Assessment of Severity

• Jaundice appears in a cephalo-caudal direction
• For clinical assessment, the Kramer’s Rule may be used to estimate the range of indirect bilirubin levels

Area	Level	Indirect Bilirubin
		µmol/L	mg/dl
Head and neck	1	68-133	4-8
Upper trunk	2	85-204	5-12
Lower trunk and thighs	3	136-272	8-16
Arms and lower legs	4	187-306	11-18
Palms and soles	5	≥306	≥18

Reference: Ministry of Health Malaysia. Clinical practice guidelines: management of neonatal jaundice (second edition). 2015.