Effect of storage and freezing on unbound bilirubin measurement

Abstract

Background-Unbound bilirubin (B f ) is a better predictor of bilirubin toxicity than total serum bilirubin (TSB) in the postnatal period. The Food and Drug Administration approved peroxidase test for B f analysis is not currently available in clinical laboratories. The samples are often stored at varying temperature and for varying duration before B f analysis.

Prevalencia de síndrome de Gilbert y sus determinantes genéticas en población chilena

“…De hecho, un estudio reciente demostró que sueros almacenados a -20°C muestran una disminución significativa en los valores de BT a partir de 2 semanas, comparados con determinaciones en muestras frescas. El almacenamiento a -80°C disminuye este artefacto 30 . En la ENS2009-2010, el lapso transcurrido entre la toma de muestra y la determinación de bilirrubina fue de 167 a 526 días.…”

Bilirubin Albumin Binding and Unbound Unconjugated Hyperbilirubinemia in Premature Infants

“…Each sample was centrifuged and analyzed immediately for UB or stored in a −80°C freezer for not more than a month before analysis of UB. (18) The validated modified peroxidase test was performed to measure UB using the Food and Drug Administration approved Arrows UB analyzer UA-1 (Arrows Co, Ltd; Osaka Japan) with two enzyme concentrations of pre-calibrated peroxidase (Arrows Reagent Kit, Arrows Company, Osaka, Japan). (19) The first order rate constant for the oxidation reaction or the peroxidase enzyme activity of 1 was confirmed using bilirubin standard (0.67 mg/mL) and albumin-free solution (i.e.…”

Unbound Unconjugated Hyperbilirubinemia Is Associated with Central Apnea in Premature Infants

“…Each sample was centrifuged and analyzed immediately for UB or stored in a −80° C freezer for not more than a month before analysis of UB. (9) TSB was measured in the chemistry laboratory using colorimetric method. UB was measured by the validated modified peroxidase method at two enzyme concentrations of pre-calibrated peroxidase (supplied by Arrows Co, Ltd; Osaka Japan) using the Food and Drug Administration approved Arrows UB analyzer UA-1 (Arrows Co, Ltd; Osaka Japan).…”