E. Visitors
Visitors to patients who have S/KI TB should be given respirators to wear while in the isolation room,
and they should be given general instructions on how to use their respirators (CDC Guidelines MMWR,
October 28, 1994, Vol. 43, No.RR-13, p28)
F. Discontinuation of AFB Precautions
The following criteria must be used for discontinuing precautions for patients in the Medical Center
with S/KI TB:
1. The patient is found not to have tuberculosis or
2. The patient is on appropriate therapy, (It should be noted that appropriate therapy needs to
be defined at the local level based on community incidence of multi-drug resistant tuberculosis,
tuberculosis susceptibility testing of facility isolates, and the specific known susceptibilities of the patient's
organism) and
A positive clinical response to therapy and
Three consecutive negative AFB smears collected on separate days
IV. Engineering Controls
A. General Guidelines
The CDC guidelines are the minimum acceptable level, and should be increased where required to satisfy
other mandated criteria or engineering requirements. Where current VA criteria exceed the CDC
guidance, the use of VA criteria is recommended. However, if existing configuration or cost do not allow
compliance to more stringent VA criteria, then the CDC guidance is the minimum acceptable.
1. Six total air changes per hour are likely to reduce the concentration of bacteria in the room.
For the purposes of reducing the concentration of droplet nuclei, TB bedrooms and treatment rooms in
existing health care facilities should have an airfiow of greater than or equal to six air changes per hour.
Where feasible, this airflow rate should be increased to greater than or equal to 12 air changes per hour.
New construction or renovation of existing health care facilities should be designed so that TB bedrooms
achieve an airflow of greater than or equal to 12 air changes per hour.
2. Air from TB bedrooms and treatment rooms for S/KI TB patients should be exhausted to
the outside. The air should be exhausted in a manner and location so that it is not pulled into intake louvers
or windows without significant dilution. At a minimum, the exhaust shall be 25 feet from any air intake.
However, other factors, such as wind direction, wind velocity, stack effect, system sizes, and height of
buildings must be evaluated and location of intake and exhaust outlets adjusted as required. If, in some
instances, recirculation of air into the general ventilation system from such rooms is
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