Micro - Specimen Collection & Handling
Instructions for Completion of the Request Form and Sample Labelling
- Confirm the identity of the patient.
- The patient's name must be on all specimen containers
- A request form must accompany all specimens to the laboratory.
The form should show clearly the patient's details including:
- Three unique patient identifiers: First name, Surname, Date of birth, Hospital/Clinic number, Medical Record Number (MRN)
- Type of specimen and anatomical site, where appropriate (eg swabs)
- Date and Time of sample collection
- Tests required
- All relevant clinical data including: antibiotic treatment, foreign travel, pregnancy, underlying conditions the patient may have (eg diabetes, cystic fibrosis) and other conditions that may affect the patient's immune system
- Risk status if applicable (legal requirement) eg high risk specimen
- If either the request form is not completed correctly or the sample is not adequately labelled a request may be rejected as processing the samples may result in misidentification of the patient constituting a clinical risk.
- Whenever possible samples should be collected before the administration of antibiotics.
- Instrument, containers, and other equipment coming in direct contact specimens must be sterile.
- The material to be cultured must not come in contact with chemicals or germicides eg disinfectants for genital cleansing prior to the collection of urine cultures.
Procedure for "High-Risk" Specimens (Hazard Group 3)
- High risk specimens are those that could, potentially, contain Hazard group 3 pathogens. For a list of organism categories refer to the Advisory Committee on Dangerous Pathogens (ACDP) Approved List of Biological Agents (http://www.hse.gov.uk/pubns/misc208.pdf)
- High-risk specimens must be labelled with the appropriate biohazard sticker and placed in a sealed outer risk container during transport to the laboratory.
- The accompanying request form must also carry the biohazard label, as well as sufficient clinical data to enable laboratory staff to know what special precautions are necessary in the laboratory.
Specimen problems and Sample rejection
Specimens arriving to the laboratory that are correctly labelled and sealed will be dealt with promptly and without delay. Unlabelled specimens will not normally be processed. Please ensure that all lids are secured before transporting the specimen as leaking samples cannot be processed and will need to be retaken.
Requesting additional examinations on Specimens already sent
Where possible the laboratory will perform additional investigations on specimens that have already been received. Additional tests should be requested as soon as possible after the specimen is sent.
Microbiology specimens do not store well. Besides, some of the procedures used in the initial investigation may use the entire sample or render it unsuitable for further investigations.
The types of specimen required by the laboratory are listed in the table below. It is important that we receive the correct specimen type in the correct container. Specimens for bacteriological investigation should be collected into a sterile laboratory specified container. This ensures that contaminating organisms do not interfere with the interpretation of the test and that the container is free of substances that may affect the culture results.
Key Factors That May Affect Test Performance/ Results
- Delay in transport: This may affect the viability of pathogens and allow overgrowth of normal flora or contaminating organisms. The morphological appearance of cells may also be affected.
- Excessive temperature: In general, bacteriology samples should be kept under cool conditions. As the temperature increases bacterial activity may also increase leading to misleadingly high counts of pathogens or overgrowth of normal or contaminating flora. Also, high temperatures may kill the target organism. Some organisms do not tolerate cooling well and so there is no substitute for rapid transport. The use of boric acid containers should be considered whenever the transport of urines to the laboratory is delayed.
- Inappropriate specimens, site or transport medium: If the specimen is taken from the wrong site or it is the wrong type of specimen (eg swab instead of pus) or it is put in the wrong transport medium (eg viral instead of bacterial transport medium, dry swabs) then the optimal recovery of the target organism(s) will not be possible.
- Insufficient Clinical Data: It is essential that the appropriate clinical information is supplied. This will include the specific anatomical site and the sample type, history of any foreign travel, any contact with animals and occupation if relevant. Failure to provide relevant information may result in the most appropriate investigation not being performed.
Transportation of Specimens
- Specimens should be collected into sterile, leak-proof containers.
- The specimen should be sealed in a specimen bag and the attached request form completed with full patient information, clinical history and specimen details as appropriate.
- The specimen should be transported to the laboratory as soon as possible after collection to allow the most accurate interpretation of results.