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Urine analysis

What's it all about?

Doctors can learn a lot about a patient from their urine. For example, they can discover whether the patient has kidney disease or diabetes.

Experience shows that when students are introduced to this activity, they are either alarmingly keen to produce urine samples, or desperately keen to avoid doing so. To avoid such worries, some simple chemistry is used to mimic the look and (amazingly) the smell of urine for some tests. It really does look convincing, especially when the technicians bring out brimming containers of warm, faintly yellow liquid! The tests are for colour, odour, pH, and the presence or absence of protein and glucose.

Student notes

There are four tests to do on each sample of urine:

Examination by eye and nose

Examine the urine carefully by eye and ... nose! Comment on the colour of the urine. Try to use words like yellow, amber, dark and pale. Examine the sample for its odour (smell). Also note whether the sample is clear or cloudy. Record your observations in your Urine Testing Chart.

pH testing

Now you need to find out the pH of the unheated urine. Dip a piece of universal indicator paper into the urine. Quickly take it out, and leave it for 30 seconds. Compare the paper colour with the pH colour chart, and note the pH number on your Urine Testing Chart.​​​​

Testing for protein

Next, find out if the sample contains protein. You are doing this because protein leaks into the urine if the kidneys are damaged. Divide the sample equally between two test tubes. Put one tube into the hot water bath, and leave the other at room temperature. After a few minutes, take the test tube out of the water bath, and compare the heated and unheated urine. If the heated sample is more cloudy, it contains protein. Note your result in your Urine Testing Chart. Flush away the heated urine, and keep the unheated sample.​​​​

Testing for glucose

The last test is to find out if the urine contains glucose, which may indicate that the patient has diabetes. Dip a glucose test strip into the unheated urine sample, and immediately take it out. Count to ten, then check the colour with the colour chart. Record the amount of glucose shown by the colour of the test strip.​​​​

Urine Testing Chart

Record your results for Sample X in the first table of your Urine Testing Chart (a simple version is shown below).

Urine Testing Chart
Name:
colour  
odour  
universal indicator colour  
pH  
unheated sample  
heated sample  
glucose test strip result  

Record your results for Samples A to D, and the villain’s sample, in the second table of your Urine Testing Chart (a simple version is shown below).

  Sample A Sample B Sample C Sample D villain
colour          
odour          
pH          
protein          
glucose          

Who was the villain, and why?

A dastardly crime has been committed in the vicinity of the toilets. The villain's urine and samples from four suspects have been collected. Your task is to find out who did it.

Carry out each test on Sample X to make sure you can carry out all the tests properly, then repeat them for Samples A to D and the villain’s sample.
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