particularly case-finding and case-management including TB treatment programme. It also needs a few hours to teach a very basic bacteriology of TB and role of TB laboratory in NTP. Long enough time must be allocated to the detailed laboratory procedures and their theoretical backgrounds and to the supervised or independent practices in sputum smear microscopy. Inservice training may be provided on demand and also refresher training if necessary.
Technical staff of the intermediate or central laboratory must be fully educated professional technicians who are polyvalent and possess license. The should be trained in an entire mycobacteriology technology with special emphasis on the procedures in current use of routine services and provided the necessary foundation of specialization in TB bacteriology. It takes at least six weeks to train them properly.
? LABORATORY SAFETY
Most of the workers who acquired tuberculosis in the laboratory became infected by inhaling airborne tubercle bacilli released during laboratory manipulation. Many microbiological techniques generate aerosols. For example, when loop contaminated with specimen or liquids containing live tubercle bacilli is flamed, when specimens are homogenized or blended at high speed or centrifuged, when contaminated liquids are spattered or squirted through small orifices such as pipetting or during sputum collection, dangerous aerosols are generated sometimes massively. Preventive measures have to be facilitated not to produce or relcase aerosols and also protective measures not to inhale aerosols. The laboratory workers should protect themselves and colleagues from infection, prevent false result due to cross-contamination, and identify which procedures generate aerosols.
A considerable measure of protection against airborne infection is given by the controlled airflow in the containment laboratory and by safety equipment and supplies, but none is a substitute for good technique. General safety recommendation for laboratory staff is as follows.
A. Laboratory arrangement.
The laboratory should be divided into(1) office area where only paper works is to be done. (2) room for reading cultures and recording the results, and (3) containment area where decontamination of specimens and inoculation of live organisms onto medium takes place.
B. Safe equipment and procedures.
(1) Mouth pipetting is forbidden. Pipetting devices must be used.
(2) Plastic disposable equipment should be used if possible (loops/pipettes).
(3) Syringes and needles should be avoided.
(4) Centrifuges should be equipped with aerosol-free carrier.
(5) Used pipettes and disposable equipment should be placed in a suitable disinfectant, exposed overnight and subsequently autoclaved.
(6) Discarded specimens and cultures should be placed in metal or polpropylene containers which do not leak, and then autoclaved.
(7) Suitable protective clothing should be worn in the laboratory and remove before the wearer leaves the laboratory.
(8) Gloves should be worn when handling the patient's specimens.
(9) Hands should be washed after every interruption of the work.
(10) Eating, drinking, smoking and licking labels in the laboratory must be forbidden.
C. Health supervision.
(1) Tuberculin skin tests, if negative, they should be vaccinated with BCG.
(2) Annual medical (including chest radiograpy) examination.
(3) Training in safe and correct laboratory procedures.
(4) Regular monitoring of equipment checking whether they function properly.
(5) Should record all laboratory accidents and report them to the safety officer.
