Delta bilirubin

When levels of conjugated bilirubin remain high in plasma, a fraction can bind covalently to albumin (delta bilirubin). Because it is bound covalently to albumin, this fraction has a longer half-life in plasma than does conventional conjugated bilirubin. Thus, it remains elevated during the recovery phase of obstructive jaundice after the remainder of the conjugated bilirubin has declined to normal levels this explains why some patients continue to appear jaundiced after conjugated bilirubin levels have returned to normal. 

Jaundice does not necessarily accompany cholestasis. In severe and prolonged cholestasis, particularly if obstructive, jaundice is generally always in evidence. In cholestasis, the third fraction, known as delta bilirubin, can largely be detected by means of the diazo method. This fraction is firmly bound to albumin and can therefore only be dissociated and excreted slowly. For this reason, jaundice occurring together with cholestasis tends to subside at a significantly slower rate than the increased bile acid level in the serum. In this case, jaundice is due to a reflux of bilirubin from the canaliculus into the blood or a bidirectional transport of bilirubin via the sinusoidal membrane. Sometimes jaundice is caused by metabolic dysfunction of the liver cells. Bilirubin also acts as an antioxidant. 

E73 Wu, T.W., Lauff, J.J., Kasper, M.E. and Ambrose, R.T. (1981). Delta bilirubin Preliminary physico-chemical characterization and its implications in bilirubin determinations. J. Clin. Chem. Clin. Biochem. 19, 881-882. 

E90 Powers, D., Lauff, J., Kasper, M., Ketchum, D., Connelly, L., Rand, R., Brett, E. and Hicks, J. (1982). Delta-bilirubin in pediatric patients Correlations with age and disease. Clin. Chem. 28, 1552, Abstr. 18. 

E278 Nakamura, H., Kosaka, A. and Kidani, Y. (1986). Measurement of delta-bilirubin in serum with multi-layered films. Anal. Sci. 2, 203-204. 

E316 Cantanese, G., Caquias, E., Kalir, T. and Clejan, S. (1987). Significance and diagnostic utility of delta bilirubin with special reference to alcoholic and drug induced hepatitis. Proc. Chn. Chem. 87, 30, Abstr. 32. 

E472 Ostrea, E.M., Ongtengco, E.A., Tolia, V.A. and Apostol, E. (1988). The occurrence and significance of the bilirubin species, including delta bilirubin, in jaundiced infants. J. Pediatr. Gastroenterol. Nutr. 7, 511-516. 

E672 Rosenthal, P. and Keefe, M.T. (1990). Delta bilirubin in clinical practice Comparison of Kodak Ektachem estimates and reference manual measurements. Clin. Chem. 36, 1200, Abstr. 1158. 

Igea, J., Nuno, J., Lopez-Hervas, R et al. Evaluation of delta bilirubin in the followup of hepatic transplantation. Transplant. Proc. 1999, 31(6), 2469. 

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