Acquired Immune Deficiency Syndrome (AIDS): Precautions for
Clinical and Laboratory Staffs
The etiology of the underlying immune deficiencies seen in AIDS
cases is unknown. One hypothesis consistent with current
is that a transmissible agent may be involved. If so, transmission
the agent would appear most commonly to require intimate, direct
contact involving mucosal surfaces, such as sexual contact among
homosexual males, or through parenteral spread, such as occurs
intravenous drug abusers and possibly hemophilia patients using
VIII products. Airborne spread and interpersonal spread through
casual contact do not seem likely. These patterns resemble the
distribution of disease and modes of spread of hepatitis B virus,
hepatitis B virus infections occur very frequently among AIDS
There is presently no evidence of AIDS transmission to hospital
personnel from contact with affected patients or clinical
Because of concern about a possible transmissible agent, however,
interim suggestions are appropriate to guide patient-care and
laboratory personnel, including those whose work involves
animals. At present, it appears prudent for hospital personnel to
the same precautions when caring for patients with AIDS as those
for patients with hepatitis B virus infection, in which blood and
fluids likely to have been contaminated with blood are considered
infective. Specifically, patient-care and laboratory personnel
take precautions to avoid direct contact of skin and mucous
with blood, blood products, excretions, secretions, and tissues of
persons judged likely to have AIDS. The following precautions do
specifically address outpatient care, dental care, surgery,
or hemodialysis of AIDS patients. In general, procedures
for patients known to be infected with hepatitis B virus are
and blood and organs of AIDS patients should not be donated.
The precautions that follow are advised for persons and
from persons with: opportunistic infections that are not
with underlying immunosuppressive disease or therapy; Kaposi's
(patients under 60 years of age); chronic generalized
unexplained weight loss and/or prolonged unexplained fever in
who belong to groups with apparently increased risks of AIDS
(homosexual males, intravenous drug abusers, Haitian entrants,
hemophiliacs); and possible AIDS (hospitalized for evaluation).
Hospitals and laboratories should adapt the following suggested
precautions to their individual circumstances; these
are not meant to restrict hospitals from implementing additional
The following precautions are advised in providing care to
Extraordinary care must be taken to avoid accidental
from sharp instruments contaminated with potentially
infectious material and to avoid contact of open skin
with material from AIDS patients.
Gloves should be worn when handling blood specimens,
blood-soiled items, body fluids, excretions, and
as well as surfaces, materials, and objects exposed to
Gowns should be worn when clothing may be soiled with body
fluids, blood, secretions, or excretions.
Hands should be washed after removing gowns and gloves and
before leaving the rooms of known or suspected AIDS
patients. Hands should also be washed thoroughly and
immediately if they become contaminated with blood.
Blood and other specimens should be labeled prominently
a special warning, such as "Blood Precautions" or "AIDS
Precautions." If the outside of the specimen container is
visibly contaminated with blood, it should be cleaned with
disinfectant (such as a 1:10 dilution of 5.25% sodium
hypochlorite (household bleach) with water). All blood
specimens should be placed in a second container, such as
impervious bag, for transport. The container or bag
be examined carefully for leaks or cracks.
Blood spills should be cleaned up promptly with a
disinfectant solution, such as sodium hypochlorite (see
Articles soiled with blood should be placed in an
bag prominently labeled "AIDS Precautions" or "Blood
Precautions" before being sent for reprocessing or
Alternatively, such contaminated items may be placed in
plastic bags of a particular color designated solely for
disposal of infectious wastes by the hospital. Disposable
items should be incinerated or disposed of in accord with
hospital's policies for disposal of infectious wastes.
Reusable items should be reprocessed in accord with
policies for hepatitis B virus-contaminated items. Lensed
instruments should be sterilized after use on AIDS
Needles should not be bent after use, but should be
placed in a puncture-resistant container used solely for
disposal. Needles should not be reinserted into their
original sheaths before being discarded into the
since this is a common cause of needle injury.
Disposable syringes and needles are preferred. Only
needle-locking syringes or one-piece needle-syringe units
should be used to aspirate fluids from patients, so that
collected fluid can be safely discharged through the
if desired. If reusable syringes are employed, they
be decontaminated before reprocessing.
A private room is indicated for patients who are too ill
use good hygiene, such as those with profuse diarrhea,
incontinence, or altered behavior secondary to central
nervous system infections.
Precautions appropriate for particular infections that
concurrently occur in AIDS patients should be added to the above,
B. The following precautions are advised for persons
laboratory tests or studies on clinical specimens or other
potentially infectious materials (such as inoculated tissue
cultures, embryonated eggs, animal tissues, etc.) from known or
suspected AIDS cases:
Mechanical pipetting devices should be used for the
manipulation of all liquids in the laboratory. Mouth
pipetting should not be allowed.
Needles and syringes should be handled as stipulated in
Laboratory coats, gowns, or uniforms should be worn while
working with potentially infectious materials and should
discarded appropriately before leaving the laboratory.
Gloves should be worn to avoid skin contact with blood,
specimens containing blood, blood-soiled items, body
excretions, and secretions, as well as surfaces,
and objects exposed to them.
All procedures and manipulations of potentially infectious
material should be performed carefully to minimize the
creation of droplets and aerosols.
Biological safety cabinets (Class I or II) and other
containment devices (e.g., centrifuge safety cups) are
advised whenever procedures are conducted that have a high
potential for creating aerosols or infectious droplets.
These include centrifuging, blending, sonicating, vigorous
mixing, and harvesting infected tissues from animals or
embryonated eggs. Fluorescent activated cell sorters
generate droplets that could potentially result in
aerosols. Translucent plastic shielding between the
droplet-collecting area and the equipment operator should
used to reduce the presently uncertain magnitude of this
risk. Primary containment devices are also used in
materials that might contain concentrated infectious
or organisms in greater quantities than expected in
Laboratory work surfaces should be decontaminated with a
disinfectant, such as sodium hypochlorite solution (see A5
above), following any spill of potentially infectious
material and at the completion of work activities.
All potentially contaminated materials used in laboratory
tests should be decontaminated, preferably by autoclaving,
before disposal or reprocessing.
All personnel should wash their hands following completion
laboratory activities, removal of protective clothing, and
before leaving the laboratory.
C. The following additional precautions are advised for
involving experimental animals inoculated with tissues or other
potentially infectious materials from individuals with known or
Laboratory coats, gowns, or uniforms should be worn by
personnel entering rooms housing inoculated animals.
nonhuman primates, such as chimpanzees, are prone to throw
excreta and to spit at attendants; personnel attending
inoculated animals should wear molded surgical masks and
goggles or other equipment sufficient to prevent
infective droplets from reaching the mucosal surfaces of
their mouths, nares, and eyes. In addition, when handled,
other animals may disturb excreta in their bedding.
Therefore, the above precautions should be taken when
Personnel should wear gloves for all activities involving
direct contact with experimental animals and their bedding
and cages. Such manipulations should be performed
to minimize the creation of aerosols and droplets.
Necropsy of experimental animals should be conducted by
personnel wearing gowns and gloves. If procedures
aerosols are performed, masks and goggles should be worn.
Extraordinary care must be taken to avoid accidental
or cuts with sharp instruments contaminated with body
or tissues of experimental animals inoculated with
from AIDS patients.
Animal cages should be decontaminated, preferably by
autoclaving, before they are cleaned and washed.
Only needle-locking syringes or one-piece needle-syringe
units should be used to inject potentially infectious
into experimental animals.
The above precautions are intended to apply to both clinical
research laboratories. Biological safety cabinets and other safety
equipment may not be generally available in clinical laboratories.
Assistance should be sought from a microbiology laboratory, as
to assure containment facilities are adequate to permit laboratory
tests to be conducted safely.
Reported by Hospital Infections Program, Div of Viral Diseases, Div
Host Factors, Div of Hepatitis and Viral Enteritis, AIDS Activity,
Center for Infectious Diseases, Office of Biosafety, CDC; Div of
Safety, National Institutes of Health.
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