**Question:** Which is not seen in urine in obstructive jaundice:

A. Bilirubin
B. Urobilinogen
C. Blood
D. Glucose

**Core Concept:** Obstructive jaundice is a clinical condition resulting from blockage in the biliary tract, leading to impaired bile flow and accumulation of bilirubin in the bloodstream. Bilirubin is a waste product of heme degradation, which is typically excreted in bile and urine.

**Why the Correct Answer is Right:** In obstructive jaundice, the blockage in the biliary tract prevents bilirubin from being excreted into the bile and ultimately, urine. As a result, bilirubin levels increase in the blood and skin, causing the characteristic yellow discoloration of skin and sclera (jaundice). Since bilirubin is not excreted in urine, it should not be present in the urine of a patient with obstructive jaundice.

**Why Each Wrong Option is Incorrect:**

Option A (Bilirubin): As mentioned above, bilirubin is a waste product resulting from heme degradation and is typically excreted in bile and urine. Therefore, bilirubin is present in the urine of a patient with obstructive jaundice, making this option incorrect.

Option B (Urobilinogen): Urobilinogen is a breakdown product of bilirubin excreted in urine. In obstructive jaundice, the blockage in the biliary tract prevents the excretion of urobilinogen into urine. Thus, urobilinogen should be absent in the urine of a patient with obstructive jaundice, making this option incorrect.

Option C (Blood): Blood is not a component of urine. Blood is a plasma protein, and its presence in urine would indicate hematuria (blood in urine), which is a separate clinical entity and not related to obstructive jaundice. Thus, blood is not relevant to this question and does not affect the answer.

Option D (Glucose): In obstructive jaundice, glucose is present in urine due to the impaired renal glucose reabsorption in the nephrons. However, the question asks about the absence of a specific component in urine, not its presence. Therefore, glucose is not directly relevant to this question and does not affect the answer.

**Clinical Pearl:** Obstructive jaundice is a common clinical manifestation of biliary obstruction, often caused by gallstones or tumors. Its presence can lead to complications like cholangitis, liver abscesses, and liver failure if not promptly managed. Diagnosis of obstructive jaundice involves clinical history, examination, and investigations like serum bilirubin levels, liver function tests, and imaging studies like ultrasound, MRCP, or ERCP. Treatment involves addressing the underlying cause and managing complications.