Theory & Procedure, Detection of Albumin in Urine | Additional Study Material for NEET PDF Download

Objective:

Our objective is to detect the presence of albumin in urine.

The Theory:

Let’s understand what albumin is and its role in our body.

Albumin is a protein produced by the liver and is mainly found in the blood. Its main functions are the ability to maintain intravascular oncotic pressure, meaning it keeps the fluid pressure stable within the blood vessels.  It is also a carrier protein for steroids, fatty acids, and thyroid hormones in the blood.

What is albuminuria?

A healthy kidney does not let albumin pass into the urine. A trace of protein which is less than 250 mg is found in normal urine daily.  Under pathological conditions like albuminuria, level of albumin found in urine will be way above the normal level. Albuminuria indicates some damage to the kidney, as it is starting to pass some albumin into the urine. In kidney disturbance and in high blood pressure, albumin level in urine is significantly high.

We can test the presence of albumin in urine using Heller’s test and Sulphosalicylic acid test. Heller’s test causes the precipitation of albumin and forms a white ring in the solution. When heated or treated with sulphosalicylic acid, albumin undergoes coagulation and forms a white turbidity (cloudiness) in the solution.

Learning outcomes:

• Students understand the characteristics of albumin.
• Students understand term “albuminuria”.
• Students understand the tests to detect the presence of albumin in urine sample.
• Students will be able to do the experiment more accurately in the real lab once they understand the steps through the animation and simulation.

Sulphosalicylic Acid Test

Materials Required:

Procedure

• Take 2 ml urine sample in a measuring cylinder from the urine sample bottle.
• Take a test tube and pour the urine in the test tube.
• Using a dropper, take some sulphosalicylic acid.
• Add few drops of sulphosalicylic acid in the test tube containing urine. A whitish color appears in the solution.
• Using a test tube holder, hold the test tube firmly and heat it gently upon a burner.
• A whitish or cloudy turbid solution indicates the presence of albumin in the urine sample.

Heller’s Test

Materials Required:

Procedure

• Take 5 ml concentrated nitric acid in a measuring cylinder from the reagent bottle.
• Pour the concentrated nitric acid in a test tube from the measuring cylinder.
• Using a dropper, take some urine from the urine sample bottle.
• Now incline the test tube and add sample of urine by means of a dropper along the inner side of the test tube so that it forms a layer over the nitric acid.
• The presence of white ring at the junction of two layers indicates the presence of albumin in the urine.

Simulator Procedure (as performed through the Online Labs)

You can select the type of test from the ‘Select type of test’ drop down list.

Sulphosalicylic acid Test

• Drag the dropper containing the sulphosalicylic acid towards the test tube to pour the solution into it
• Click on the knob of the burner to turn it on.
• Drag the test tube towards the burner to heat it.
• Click on the information icon to see the inference.
• You can redo the experiment by clicking on the ‘Reset’ button.

Heller’s Test

• Drag the dropper containing the urine sample towards the test tube to pour the sample into it
• Click on the information icon to see the inference.
• You can redo the experiment by clicking on the ‘Reset’ button.