Diagnostic accuracy of the Picterus jaundice Pro app for neonatal jaundice: a single-center study from Turkiye

Neonatal jaundice is common and may lead to severe complications if not identified early. Although transcutaneous bilirubinometry (TcB) is widely used for noninvasive screening, its cost limits accessibility. Smartphone-based applications such as Picterus^® Jaundice Pro (Picterus JP) may provide a low-cost alternative. We aimed to evaluate the correlation and agreement between Picterus JP and standard TcB measurements in newborns in Turkiye. This prospective observational study was conducted at a single tertiary center between December 2025 and January 2026. Newborns aged ≤ 7 days with gestational age ≥ 35 weeks were included. Paired TcB (Dräger JM-105) and Picterus JP measurements were obtained from the sternal area under standardized conditions. Correlation was assessed using Spearman's rank correlation. The agreement was evaluated using the Bland-Altman analysis and the concordance correlation coefficient (CCC). Clinically relevant disagreement was defined as an absolute difference ≥ 2 mg/dL. A total of 215 measurements from 165 newborns were analyzed. Median TcB and Picterus JP values were 6.7 mg/dL (IQR 4.85-8.9) and 7.0 mg/dL (IQR 5.3-9.9), respectively. Picterus JP showed a strong correlation with TcB (ρ = 0.78, p < 0.001). The mean bias (TcB-Picterus) was - 0.94 mg/dL, with 95% limits of agreement from - 5.35 to 3.47 mg/dL. The CCC was 0.73. Clinically acceptable agreement was highest at lower TcB levels and declined significantly at TcB ≥ 11 mg/dL. Picterus JP demonstrates good performance as a screening tool at low-to-moderate bilirubin levels but should not replace serum bilirubin measurement near treatment thresholds.