It is essential that in infectious diseases of the respiratory tract t
he collection of samples for a directed diagnostic investigation is si
te specific. The criteria of selection for diagnostic procedures have
to aim at the greatest possible efficacy in identifying the etiologic
agent, the significance of the result and the cost-benefit-ratio. In a
first communication three sampling methods are described, which can b
e used for a direct virologic and bacteriologic determination of etiol
ogic agents.