Gastro-Intestinal Infections

Please note that it is very important to include any clinical information on the form when submitting these samples to ensure that the correct investigations are performed. This includes any recent history of foreign travel.
In cases of acute gastroenteritis acquired in the community, please submit a stool sample for bacteriological investigation. If parasitic infection is suspected, a higher diagnostic yield is obtained when three separate samples, collected over a 10-day period, are sent.
Testing for Clostridium difficile infection is routinely performed on the following samples:
· Any in-patient >2yrs of age where the sample appearance is equivalent to Bristol Stool Chart 5 to 7
· Where requested by the sender within appropriate criteria
· Where clinical information suggests long-term or extensive antibiotic usage
· Samples from patients aged >65 where the sample ‘takes the shape of the container’
· Samples from outbreaks of diarrhoea (e.g. on wards or in nursing homes) where the causative agent has not yet been identified
Repeat testing from positive patients will not be performed within 28 days, nor within 7 days from patients who have tested negative (patients testing negative in the Critcal Care Unit can be retested at 4 days). Testing for C difficile in not appropriate on infants under the age of 2 years. Formed stool samples will not be tested as this is not indicative of C difficile associated diarrhoea.
In children 5 years old and under, samples may be submitted for viral examination (Rotavirus and Adenovirus are performed routinely).
If Amoebic dysentery is suspected in a patient passing liquid faeces, the laboratory must be informed and a ‘hot’ stool sample delivered within 30 minutes of being passed, as the characteristic trophozoites are labile.
For Threadworm (Enterobius vermicularis) investigation, please submit a ‘sellotape’ slide. The tape is used to collect a sample from a patient's peri-anal area first thing in the morning, which is then stuck to a glass slide and sent to the laboratory. A patient leaflet on how to take a sellotape slide can be found in the Information for Patients section.