The collection of specimens is required for detailed observation and/or when microbiological, biochemical or other laboratory investigations are indicated.
Kyle, G. (2007) Bowel Care Part 3 - Obtaining a Stool Sample. Nursing Times; 103: 44, 24-25.
Gaye Kyle,RGN BA(Hons), MA, is senior lecturer, Faculty of Health and Human Science, Thames Valley University.
A stool specimen is collected so that a faecal culture can be undertaken in the pathology laboratory to isolate and identify organisms in the faeces that may cause gastrointestinal symptoms and disease.
Although many organisms are normally present in the faeces, some can act as pathogens, so stool samples are collected for diagnostic purposes in patients with diarrhoea and/or vomiting. Faecal culture can identify a range of organisms including Salmonella typhi, Yersinia enterocolitica and Campylobacter jejuni. Stool samples are also collected for use in screening for colorectal cancer.
A stool sample is the main diagnostic test for Clostridium difficile, and enables healthcare providers to obtain results in a matter of hours. This virulent infection is now under mandatory surveillance because of its ability to mutate and spread (Department of Health, 2006), and because it is becoming an increasing problem in infection control.
Clostridium difficile is a major cause of antibiotic-associated diarrhoea, especially among frail older people. Infections with C. difficile develop after cross-infection from another patient, either through healthcare staff or from a contaminated environment.
C. difficile causes significant morbidity and mortality - it was recently implicated in the deaths of 90 patients in an outbreak at Maidstone and Tunbridge Wells NHS Trust and was probably overall a contributing factor in approximately 270 deaths at the trust in a two-year period.
Obtaining stool specimens
Obtaining a stool specimen can provide important diagnostic information that can be used to decide how to manage the patient’s condition and the mode of treatment. However, successful laboratory investigations depend on the stool sample being collected correctly.
It is essential that a clean technique is used when collecting the stool specimen in order to avoid inadvertent contamination. Universal precautions must be used for infection prevention and control when handling all bodily fluids, and a stool sample is no exception to this rule. Handwashing with soap and water is vital in this procedure, as alcohol gel alone, for example, does not kill the spores of C. difficile (DH, 2007).
The national screening programme for colorectal cancer, which was introduced in May 2006, has set out how stool specimens should be obtained for screening. In this case the patients themselves undertake the procedure in the safety and privacy of the home. They are asked to smear samples from their bowel motion onto a special card and this is then posted back to the screening unit in an envelope that is provided.
By contrast, stool specimens collected by healthcare professionals are collected in sterile pots that have a spoon incorporated into the lid.
A disposable bedpan is required (unless the patient is using a commode to produce the sample) together with a stool specimen container (Fig 1). You will also require:
- Non-latex gloves;
- Specimen bag;
- Laboratory request form.
- Explain the procedure and the reason it is required clearly and privately to the patient. Obtain informed consent and document that it has been given.
- Where appropriate, offer the patient the choice of using either a commode at the bedside or a toilet.
- Ensure the bedside curtains are pulled tight or the toilet door is completely shut to protect the patient’s privacy.
- If the patient is using a commode ensure toilet paper is available and accessible to the patient, and that the patient also has access to handwashing facilities.
- If the patient is using the toilet, place a disposable clean bedpan (Fig 1) under the toilet seat to catch the specimen.
- Wash hands and put on gloves (Fig 2).
- When the patient has produced the sample, examine the stool for consistency, colour, blood or any other abnormality.
- Unscrew the top of the specimen container and collect the sample using the spoon provided (Fig 3). Fill the container about a third full. Secure the lid.
- Avoid specimen contamination.
- Dispose of remaining faecal matter according to local policy.
- Dispose of the bedpan (if used) according to local policy (Fig 4).
- Remove gloves and apron and dispose of them appropriately (Fig 5).
- Wash hands.
- Label the specimen container clearly and accurately (Fig 6).
- Place the specimen container in a specimen bag with the completed laboratory request form.
- If the specimen cannot be sent to the laboratory immediately, place it in the appropriate refrigerator. In some infections, however, especially those caused by parasites such as amoebiasis, the stool should remain fresh and warm. If you are in any doubt ask the laboratory for advice.
- Document all findings. Record the date and time that the specimen was obtained.
This procedure should be undertaken only after approved training, supervised practice and competency assessment, and carried out in accordance with local policies and protocols.