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Collection, Transport and Receipt of Infectious Materials

 

A large number of specimens are transported by various means between different hospitals and laboratories everyday. During transit, the containers or the packages enclosing them may be handled by many people. The containers may be involved in accidents and be damaged or broken. They may also be lost or stolen and opened by unauthorized persons. Although there are no reports of infections acquired this way, it follows that any infectious material being transported could present a hazard to any person in contact with it. Therefore, the collection, packaging, transport and unpacking should be strictly regulated. The postal and transport authorities of different countries have different regulations governing the transport of infectious materials.

Collection of Specimens

Containers - In most laboratories, disposable, screw-capped 25 ml bottles have replaced glass containers. Specimen containers must be sufficiently robust to withstand the stresses they are likely to meet and leakproof. Reusable containers (e.g. glass) must remain leakproof during their lifetime. They should be inspected before reassembly.

Blood - traditionally blood is collected with hypodermic syringes and needles and then expelled into plastic containers. There are problems with the stoppers of a lot of these containers which result in external contamination. Needle stick injuries are particularly likely to occur in resheathing the needle and this practice should either be discouraged or a safer method of resheathing be used, perhaps with the aid of certain newly developed devices. Vacuum collection tubes minimize several of the hazards and problems of taking blood and disposing safely of syringes and needles. These containers are robust, leakproof, and cannot be contaminated externally.

Faeces - faeces are probably the most hazardous material other than blood. The specimens are often collected by the patient who is rarely instructed on the proper method of collection. Patients tend to fill the container with faeces so that fermentation may lead up to a build-up of gas during transport. This may result in leakage or the cap coming off, moreover, when such as container is opened, a violent broadcast be result. The other possibility is that the outside of the container ma be contaminated. Patients should be told to defaecate on a pile of toilet paper in the lavatory pan and to remove a pea-sized portion with the spoon provided, to insert it carefully into the container and then to screw the cap on tightly.

Other Specimens - sputum specimens are probably less hazardous to handle because of the decreasing incidence of tuberculosis in developed countries. Apart from some viruses, the organisms present in sputum are rarely infectious. Nevertheless, the contamination of the outside of the container remains a problem. The risks from urine are minimal, although a small proportion of patients may excrete salmonella typhi, leptospires, hepatitis or HF viruses. It is debatable, therefore, whether any expensive precautions are needed in the case of urine. External contamination is a problem and there is a strong case for collecting urine from females in sterile large jars before transferring to a laboratory container. Other specimens such as pus and aspirated fluids are collected by professional staff which minimizes the risk of external contamination.

Labelling specimens and containers

Labels and stickers used should be self-adhesive for obvious reasons. There is much controversy about "Danger of Infection" and "High Risk" labels. These are often used for specimens where there is a special risk such as HBV or HIV. The problem is that these labels may give a false sense of security to the staff who should any specimens as potentially infectious with dangerous pathogens. Specimens labelled "Danger of Infection" should be placed in self-sealing plastic bags. Pins and staples should not be used as they may prick the hands of any persons handling the bag. Request forms should be separate from the specimen.  

Transport of Specimens

Transport within hospitals - the DHSS code of practice stipulates that leak-proof (bottoms and seams should not leak) trays or boxes should be provided for the transport of specimens from wards to the laboratory, and these should be able to withstand autoclaving or overnight exposure to disinfectant. Staff carrying the specimens should wear overalls and encouraged to hand wash frequently. The taking of specimens into canteens and kitchens should be forbidden.

Transport between hospitals - the HSAC (1991) requires that "special" secure transport boxes with secure lids. These must be capable of withstanding autoclaving and prolonged exposure to disinfectants. These boxes should be inspected daily for leakages and decontaminated and washed out at least weekly.

By inland post - the Post Office Guide (1986) stipulates that Hazard Group 4 agents must not be posted. Hazard Group 3 material must have a "Danger of Infection" label on the container (but not on the outside of the box). The container used must be robust and cocooned in enough absorbent packing material to retain the contents in the event of leakage or damage to the container. It is wise to place the container in a self-sealing plastic bag although this is not required by the Post Office. The material must be sent by first class mail.

By air mail or air freight - before any material is sent to another country by air mail, the sender and receiver must ascertain that it is acceptable to the authorities of that country. The material should be placed in a watertight "primary container" which is then packed in a watertight "secondary container" and the whole packed in an "outer container" All containers must be approved by the postal authorities. The following documentation are required; (1) An International Air Traffic Association’s Shippers Certificate for Restricted Articles, (2) Labels giving contents, description and quantity of infectious substance, (3) Green customs label, (4) Official address label.

Receipt of infectious material

There is clearly a difference between the hazards posed by packages sent to a specialist or reference laboratory and those to a routine diagnostic laboratory. The former are likely to contain cultures or concentrates of infectious agents whereas the bulk of the latter is not particularly infectious. It is advisable that cultures and such specialized materials are unpacked in the laboratory by professional staff. There is concern over the use of clerical staff for receiving and documenting specimens. It is not unusual to see food and drink being consumed by clerical staff near the specimens. The disturbing large number of untrained staff who acquire infection in the laboratory undoubtedly include clerical and reception staff. Therefore it is essential that clerical staff handling specimens should be given some form of training in the safe handling of specimens. Any specimen in a plastic bag which carries a Danger of Infection label should not be removed from that bag. The accession number can be put on the outside of that bag. Leaking or broken specimens should not be touched, nor should any others in the same box or tray. Provision should be made for a member of the professional staff to deal with them. These specimens should not be allowed to stray to other parts of the room.  

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Decontamination