unconjugated bilirubin


Also found in: Dictionary, Thesaurus, Encyclopedia.
Related to unconjugated bilirubin: indirect bilirubin

in·di·rect re·act·ing bil·i·ru·bin

the fraction of serum bilirubin which has not been conjugated with glucuronic acid in the liver cell; so called because it reacts with the Ehrlich diazo reagent only when alcohol is added; increased levels are found in hepatic disease and hemolytic conditions.

unconjugated bilirubin

the majority of bilirubin in plasma. See bilirubin.

bilirubin

an orange bile pigment produced by the breakdown of heme and reduction of biliverdin; it normally circulates in plasma and is taken up by liver cells and conjugated to form bilirubin diglucuronide, the water-soluble pigment excreted in the bile. Failure of the liver cells to excrete bile, or obstruction of the bile ducts, can cause an increased amount of bilirubin in the body fluids and thus lead to obstructive or regurgitation jaundice.
Another type of jaundice results from excessive destruction of erythrocytes (hemolytic or retention jaundice). The more rapid the destruction of red blood cells and the degradation of hemoglobin, the greater the amount of bilirubin in the body fluids.
Most bilirubin is excreted in the feces. A small amount is excreted in the urine as urobilinogen.

conjugated bilirubin
bilirubin that has been conjugated, mainly to glucuronic acid, in the liver and gives a direct result to the van den bergh test. High blood levels indicate obstructive or hepatocellular origin of the jaundice.
delta bilirubin
bilirubin diglucuronide
see conjugated bilirubin (above).
free bilirubin
see unconjugated bilirubin (below).
bilirubin toxicity
unconjugated bilirubin
bilirubin that has not been conjugated in the liver. It gives an indirect reaction to the van den bergh test. A high level of it in the blood is indicative of hemolysis or a lack of bilirubin clearance by the liver. Called also free bilirubin.
References in periodicals archive ?
The second type, conjugated bilirubin, is formed when hepatocytes process unconjugated bilirubin for excretion.
To prevent unconjugated bilirubin being deposited in tissues it is bound to albumin (a protein) and then transported in the blood to the liver where it is converted to its conjugated form by an enzyme called glucuronyltransferase (England, 2010; McIntosh and Stenson, 2008).
Indirect bilirubin is calculated by subtracting the direct value from the total value and provides an estimate of the unconjugated bilirubin in the serum.
There is only one case report describing high levels of unconjugated bilirubin in a pregnant patient with Crigler-Najjar syndrome as a cause of quadriplegia in the neonate.
These include concentration of unconjugated bilirubin high enough to exceed the bilirubin-binding capacity of albumin, due to severe hemolysis from Rh isoimmunization (18); bilirubin displacement from albumin by competing or affinity-altering molecules such as sulfisoxazole (19) or free fatty acids (20); and disruptions of the blood-brain barrier that allow bilirubin-protein complexes to enter the brain.
In addition, samples being collected for direct bilirubin analysis should be "promptly cooled to 4[degrees]C" and minimally kept at room temperature to prevent their degradation from artificially inflating the unconjugated bilirubin concentration.
ASSURANCE[TM] Interference Test Kit is made with human-sourced triglyceride-rich lipoproteins to evaluate lipemia interference; human hemolysate to evaluate hemolysis interference; human albumin and gamma-globulins to evaluate protein interference; as well as conjugated and unconjugated bilirubin to evaluate icterus interference.
In one of our previous publications we have concluded that raised serum bilirubin, unconjugated bilirubin, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were predictors of mortality in patients with mushroom poisoning.
Hyperbilirubinaemia typically results from the deposition of unconjugated bilirubin, manifested in skin and mucus membranes.
Assays were completed in batches on the Cobas Integra 400 (Roche) [[alpha]-1 antitrypsin (A1AT), [alpha]-1 acid glycoprotein (AGP), complement component 3 (C3), C4, ceruloplasmin, C-reactive protein (CRP), haptoglobin, IgG, IgA, IgM, soluble transferrin receptor (STfR), transferrin] and the VITROS 5,1 FS chemistry systems analyzer (Ortho Clinical Diagnostics) [albumin, alkaline phosphatase (ALP), alanine aminotransferase (ALT), amylase, aspartate aminotransferase (AST), unconjugated bilirubin, calcium, cholesterol, creatine kinase (CK), chloride, C[O.
Unconjugated bilirubin is produced by the breakdown of haem, which is found in red blood cells.