What can be detected in a stool sample in The UK?

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Your poo tells a lot about your internal health.

The food you eat will affect your health. At the same time, the faeces and urine coming out of your body reflect your health. Whenever you have abdominal and intestinal complaints, the doctor will ask you to go through a faecal (or stool) examination. Why a stool test is done? What could be found in your stools? These things might interest you. Let me help you know.

Why go for stool sampling?

If you go to the doctor to complain of diarrhoea, bloating, constipation, mucus or blood in the stools or abnormal odour and colour of the poo, it is highly likely that he will suggest you undergo a stool test. The stool testing is used for;

  • The diagnosis of conditions e.g., ulcerative colitis, Crohn's disease, parasites (live parasites and eggs), bowel cancer screening etc.

  • It is also suggested before the expected surgical procedures.

  • It could be useful as a part of regular health monitoring.

How stool testing is done?

The stool samples are collected in an empty plastic food container. These containers are sterile and specially designed for the purpose. After the collection, these containers are placed in a sealed plastic bag and dispatched to the laboratory.

In the laboratory, the plastic wrap is opened up and the sample is subjected to three types of tests.

Macroscopic examination

It will find out any abnormal colour, odour, consistency and presence of blood and mucus. Some parasites (e.g., roundworms) could be seen with the naked eye. However, you will not be able to identify smaller parasites and their eggs and you will need microscopic stool tests.

Microscopic examination chemical analysis

The consumption of raw or undercooked poultry and unhygienic habits will result in parasitic infections.

The microscopic examination will help you to see;

  • Identify the eggs and smaller parasites.

  • The cancerous cells are associated with colorectal cancer. Some tests can detect the DNA of the germs present in the stools.

Chemical analysis

The body and different organs release various biomarkers (molecules) in response to any stress. These biomarkers are also found in the faeces and their presence is an important indicator of internal health.

  • The presence of calprotectin in the faeces is an indication of inflammatory conditions. If detected, it is quantified as its quantity is related to the severity of inflammatory conditions e.g., IBD.

  • The presence of fats. The problems in fat digestion will result in abnormal fat accumulation in the faeces. If so, further tests will be recommended to know the reason.

  • The presence of the elastase enzyme is an indication of pancreatic health.

Microbiological examination

The bacterial cultures could be recommended to check for any bacterial infections e.g., bacterial diarrhoea. For this, the samples are dispatched to the microbiology lab.

These tests could detect the presence of different common pathogenic bacteria e.g.,

  • Escherichia coli

  • Campylobacter

  • Shigella

  • Salmonella etc.

If viral diarrhoea is suspected, the presence of viruses in the stool sample can be detected by other tests e.g., polymerase chain reaction (PCR).

Bottom-line

Most common pathogenic bacteria and protein biomarkers are excreted in the faeces. The stool sample testing should therefore be a part of regular health screening.

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