Work

The Effect of Conjugated Bilirubin on the Measurement of Unbound Bilirubin

Year: 2025

Type: article

Abstract: AIM: Unbound bilirubin (Bf) is a stronger predictor of neurotoxicity in newborns than that of total serum bilirubin (TSB). Standard Bf assays rely on peroxidase methods (e.g., Arrows analyser), whereas UBCheck employs a near-infrared fluorescence sensor. Because conjugated bilirubin (CBR) levels are often elevated in infants, they may alter Bf measurement accuracy, particularly with peroxidase-based methods. This study compared CBR effects on Bf measurement results from the UBCheck and Arrows assays and evaluated whether they reflected albumin displacement, assay interference, or both. METHODS: Bilirubin-albumin complexes were spiked with CBR (0.1-5 mg/dL). Bf was measured with both assays using a three-stage paired-sample protocol to assess displacement and interference. RESULTS: At CBR ≤ 0.2 mg/dL, both assays yielded comparable Bf values. At 0.5-3 mg/dL, Arrows showed 12%-120% Bf increases, while UBCheck remained stable. At 4 mg/dL, UBCheck rose 20%, and Arrows increased by 220%. High CBR acted as both interferent and displacer. CONCLUSIONS: In the presence of neonatal CBR concentrations, UBCheck provides reliable Bf measurements, whereas Arrows substantially overestimates Bf, limiting its clinical utility.

Source: Acta Paediatrica

DOI: 10.1111/apa.70357

Authors: Alan Kleinfeld, Andrew Huber, William Oh, Thomas Hegyi

Institutions: Fluoresprobe Sciences (United States), Brown University, Rutgers, The State University of New Jersey

Language: English

Topic: Neonatal Health and Biochemistry

Subfield: Pediatrics, Perinatology and Child Health

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: hybrid

Estimated APC paid: $4,480