Which abnormal finding on urinalysis is most firmly associated with liver issue?

The presence of elevated urine bilirubin is most firmly associated with liver issues. Bilirubin is a byproduct of the breakdown of red blood cells and normally is processed by the liver. When the liver is functioning properly, it conjugates bilirubin to make it water-soluble, allowing it to be excreted in bile. If there is liver dysfunction or bile duct obstruction, this process is impaired, leading to the accumulation of conjugated bilirubin in the blood and its subsequent excretion into the urine.

The presence of bilirubin in urine indicates that there is an issue with the liver or bile-excreting systems. Conditions such as hepatitis, cirrhosis, or obstruction of the bile duct can lead to an increase in urinary bilirubin, thereby serving as a strong indicator of liver-related pathology.

The other findings listed, such as glucose, RBC casts, and WBC casts, are more indicative of conditions affecting the kidneys or urinary tract rather than the liver. Glucose in urine typically points towards diabetes mellitus or renal glycosuria, while RBC casts are associated with glomerular damage, and WBC casts suggest infections or inflammation in the renal system. Thus, elevated urine bilirubin stands out as the most direct indicator of liver issues