Test For Presence Of Bile Salts In Urine

Table of Contents

• Aim
• Theory
• Materials Required
• Procedure
• Observation and Conclusion

To perform a test which detects the presence of bile salts in the given sample of urine.

What is Bile?

Bile is a fluid, that typically appears yellowish-green in colour. It consists of organic molecules such as bile acids, bilirubin and cholesterol, and water. The functions of Bile include:

• Fat digestion and absorption.
• The elimination of bile salts, which are carried out by secreting into bile.

Refer more: Digestion and Absorption.

How are bile salts formed?

Bile is generated by the liver and is stored by the gall bladder. Whenever food is ingested, bile is released into the duodenum. Bile salts formation is initiated with the disintegration of red blood cells. Rupturing of the damaged and old red blood cells is brought about as they pass through the liver or spleen.

Iron is removed and haemoglobin is disintegrated by the macrophages from the haeme element. This portion of the haeme, which is free from iron is transformed into a green pigment known as biliverdin and subsequently into a yellow-orange pigment known as bilirubin.

The bilirubin in the liver is extracted as a bile pigment, which later moves into the small intestine and further into the large intestine.

Let’s look into the different types of tests performed to detect the presence of bile salts in the given urine sample.

1. Smith’s Test

• Test tube.
• Dropper.
• Urine sample.
• Smith’s reagent.
• Measuring cylinder.

• Take a clean and dried test tube.
• Add 1ml of Smith’s reagent into the test tube using a measuring cylinder.
• With the help of the dropper take a few drops of the collected urine sample from the bottle.
• Now hold the test tube in an inclined position and slowly add the urine sample using a dropper on the sides or walls of the test tube.
• Observe and make a note of the changes.

The presence of bile salt in the given urine sample is indicated by the formation of a green coloured ring at the intersection of both layers.

2. Pettenkofer’s Test

Material Required

• Test tube
• Spatula
• Dropper
• Sucrose
• Urine sample
• Measuring cylinder
• Concentrated H₂SO₄

Procedure

• Take a clean and dried test tube.
• Add accurately 2ml of urine sample into the test tube using a measuring cylinder.
• With the help of a spatula, add some sucrose into the tube holding the urine sample.
• With the help of a measuring cylinder, accurately measure 2ml of concentrated H₂SO₄.
• Now hold the test tube in an inclined position and slowly pour the measured concentrated H₂SO₄ through the sides of the test tube.
• Observe the changes taking place in the test tube.

Observation And Conclusion

The presence of bile salt in the given urine sample is indicated by the formation of a red ring between both layers.

For more information on bile salts in urine and other related biological concepts and experiments, visit us at BYJU’S Biology.

Related Links: