Comparison of Transcutaneous and Total Serum Bilirubin Measurements in Neonates With Jaundice: A Prospective Study From Nepal

Background: Neonatal jaundice is very common (≈ 60% of term and 80% of preterm newborns) and, if severe, can lead to bilirubin neurotoxicity. The gold-standard total serum bilirubin (TSB) measurement is invasive and time-consuming. Transcutaneous bilirubinometry (TcB) is a quick, noninvasive alternative using a skin bilirubinometer. Leading guidelines recommend universal predischarge jaundice screening using TSB or TcB. However, TcB is underused in Nepal, and its accuracy – especially in preterm neonates – needs validation. This study compares TcB and TSB in jaundiced neonates. Methods: In a single-center prospective study (Oct 2023–Sep 2024) at Paropakar Maternity and Women’s Hospital (Kathmandu, Nepal), 66 neonates with clinical jaundice were enrolled. TcB was measured at the mid-sternum and forehead using a calibrated JM-103 bilirubinometer (Konica Minolta). Venous blood was drawn (within 30 min of TcB) for TSB (BR-5200 spectrophotometer). Mean TcB values (average of three readings per site) were compared with TSB. Statistical analysis included Pearson correlation, Bland–Altman agreement, and ROC curves (SPSS v20). A p-value < 0.05 was considered significant. Results: Among the 66 neonates, 66.7% were male. Most were term (66.7%) and appropriate-for-gestational-age (63.6%). The mean birth weight was 2656.5 ± 795.9 g. Mean TcB values exceeded TSB by ~ 1–2 mg/dL across categories, a statistically significant difference in all groups except large-for-gestational-age (LGA) neonates. Crucially, TcB and TSB were highly correlated. Pearson r was 0.931 (p < 0.001) in term neonates and 0.896 (p < 0.001) in preterm neonates. Among small-for-gestational-age neonates, r was 0.948 (p < 0.001). TcB measured at the sternum versus forehead did not differ in mean value (no significant site effect). Both sites correlated well with TSB (r = 0.923 for sternum vs 0.894 for forehead, p < 0.001 each). Bland–Altman analysis showed a mean TcB–TSB bias of + 1.5 mg/dL (95% limits − 6.8 to + 9.9). ROC analysis for detecting significant hyperbilirubinemia yielded AUC ≈ 0.63 for both TcB and TSB in preterm and term subgroups; TcB thresholds achieved high sensitivity (~ 85%) but low specificity (≈ 45%). Conclusions: Transcutaneous and serum bilirubin levels were strongly, positively correlated across all subgroups (term, preterm, SGA), indicating that TcB is a reliable noninvasive screening tool for neonatal jaundice. Sternum readings correlated slightly better than forehead. Given its rapid, painless measurement, TcB can be used to screen and monitor jaundice, reducing unnecessary blood draws. However, TcB tends to overestimate TSB by about 1.5 mg/dL, and elevated TcB readings near treatment thresholds should be confirmed by TSB. Practically, universal TcB screening (24–48 h postnatal) as endorsed by WHO and AAP could be implemented, with follow-up TSB as needed. Larger multicenter studies and cost-benefit analyses are recommended to confirm these findings in broader settings.