Since October 2016 the Microbiology laboratory has been accredited to the international standard ISO15189:2012, ‘Medical laboratories – Requirements for quality and competence’. Its schedule of accredited tests can be found at: www.ukas.com
Labelling of request forms and specimen containers
Where possible, samples should be requested electronically using the Hospital iCM system, or GP ICE system. This has the benefit of reduction in transcription errors, increases data legibility, saves paper and saves laboratory time in booking samples.
If paperless electronic ordering is not available then samples will be accepted if adherence to the following information is made.
The appropriate microbiological investigations that are performed on a specimen are selected on the basis of data included on the request form, and results are also interpreted in the light of this information. Consequently, in addition to the usual requirements for patient name, hospital and NHS number and date of birth, it is important to include adequate clinical information on each form. Please complete a fresh request form for each sample, as forms may be required to be sent to separate areas of the laboratory. Details to be included and the reason for their inclusion are given below:
• Patient’s address: In some cases, this is important epidemiological information (e.g. identification of clusters of infections in the community, contact tracing, etc.).
• Date of birth: Some microbiological tests performed on the specimen may be selected purely on grounds of age (e.g. examination for rotavirus in stool specimens of children)
• Nature of specimen: This must be specified. For example, straw-coloured fluid in a container could be urine, aspirate from a joint, peritoneal fluid or CSF .
• Relevant history/clinical information: The history may indicate which microbiological tests are relevant. Interpretation and appropriate further examination of the culture is often dependent on the given clinical history .
• Site, nature and duration of infection: Different parts of the body tend to have their own flora which may be commensal (harmless) at one site and pathogenic at another (e.g. Staphylococcus aureus may be carried asymptomatically in the nose but be the cause of an infected surgical wound). Please also indicate date of onset of infection and details of recent surgical operations
• Antibiotic therapy: Failure to include details of antibiotic therapy may result in a misleading report. The antibiotic may inhibit growth of the causative organism or select resistant strains which colonise the site. This information also ensures that appropriate susceptibility tests are performed on significant isolates.
• Date and Time of Collection: Different organisms survive for varying periods and some grow well at room temperature. If normal flora are present, their survival and subsequent multiplication may make results hard to interpret.
Rejection of specimens
Sample and request form information must be compatible and complete. Unlabelled specimens, specimens where information on the sample container and the request form do not match, or specimens received without an accompanying request form (unless it is an iCM or ICE sample) will not be examined. However, for unrepeatable specimens (e.g. CSFs, blood cultures), an attempt will be made to contact the sender in order to clarify the situation, and the samples may then be processed in the usual way. An entry shall be made on the report pertaining to the discrepancy.
Samples require a minimum number of 3 points of identification
The points of identification are:-
• NHS number
• Full Name
• Date of birth
• Hospital Number
If request does not contain the correct amount of details as described above the following report will be issued.
“There was insufficient information with this request to uniquely identify the patient; therefore the sample has not been examined.
“Please arrange a fully labelled repeat sample, if still clinically indicated”
Please ensure that GP/consultant name and name/bleep/telephone number of requester are stated.
These enable laboratory staff to communicate quickly with medical staff if there are any queries. The name of the consultant or GP also helps in monitoring requesting patterns and workload. The bleep number is particularly helpful for hospital inpatients.
These should be handed separately to transport staff, who will ensure that they are delivered appropriately to laboratory staff. This facility is for requests requiring results for the immediate management of the patient. Urgent requests are regularly audited.
Specimens for urgent analysis, which are delivered to the laboratory by Taxi or other transport, should be hand delivered to the appropriate laboratory and should not be left at the main reception. The IATA Dangerous Goods (DG) Regulations state that members of the public should be protected from the risks of potentially infectious substances. A code of practice for staff involved in specimen transport is available on request from the Pathology Directorate office.
If an urgent (telephoned) result is required this should be noted on the request form and the laboratory informed by telephone. The ‘red spot’ system does not apply to Microbiology samples. For urgent specimens outside normal working hours see On-Call Repertoire below.
Some specialist tests not performed by this department will be sent to approved reference laboratories. When this occurs, the initial report will state that a reference laboratory report is to follow. When the final report is issued, the reference laboratory will be identified. More information about the reference facilities used will be published on this website in due course.
Specimens associated with forensic legal investigations must be accompanied by a “Chain of Evidence” form. This form can be obtained from the Microbiology Department (Tel Ext: 43375).
On arrival at the laboratory explain the nature of the specimen and request the attendance of a senior member of staff. Out of hours contact the oncall Biomedical Scientist.
The best results are obtained when an appropriate, well taken specimen, in the proper container, is delivered to the laboratory promptly and relevant clinical information is provided on the request form.
General guidelines on specimen collection are:
• Do not send specimens in non-sterile containers
• Specimens should be obtained before antimicrobial agents have been administered
• An adequate quantity of material should be obtained for complete examination.
• Always send pus rather than a swab of the pus.
• The specimen taken should be representative of the disease process. For example material swabbed from the opening of a sinus tract is more likely to yield commensal skin flora than material obtained by curettage or biopsy of the base of the tract.
Care must be taken to avoid contamination of the specimen by micro-organisms normally found on the skin and mucus membranes. Sterile equipment and aseptic technique must be used for collecting specimens particularly for those from normally sterile sites.
For safe disposal of materials used in the collection of specimens (gloves/sharps etc) please refer to your local guidelines.
Material must be transported promptly to the laboratory. Fastidious organisms may not survive prolonged storage or may be overgrown by less fastidious organisms before culturing (ideally samples should reach the laboratory no later than 24 hrs after taking the specimen).
Please contact the laboratory if there is any doubt about the most appropriate specimen to take or concerning the availability of a test.