NEW DIRECTIONS IN DIAGNOSTICS

Background. Infectious diseases are still a significant clinical probl em in children, and accurate identification of the causal pathogen pla ys an important role in clinical management, The availability of an et iologic diagnosis enables the clinician to make appropriate therapeuti c decisions and to avoid the indiscriminate use of antibiotics, The av ailability of a microbiologic diagnosis and the susceptibility profile of the pathogen allows the prompt initiation of suitable antibiotic t reatment, However, the usefulness of current culture and identificatio n methods is limited by the time needed and by their sensitivity and s pecificity, Also some microorganisms are difficult or impossible to gr ow in the laboratory. Objectives. To review the newer and more rapid d iagnostic techniques that are becoming available and consider their ap plication in the diagnosis of specific infections. Discussion. Immunoa ssays have many advantages and it is hoped that new optical immunoassa ys will overcome the problems of poor sensitivity, Nucleic acid amplif ication techniques have enormous potential in the diagnosis of infecti ous diseases because of their high specificity and sensitivity and the speed with which the results can be obtained, However, there are stil l a number of difficulties that must be overcome before these methods can be widely adopted for routine testing. These techniques may be par ticularly relevant for the rapid diagnosis of streptococcal pharyngiti s, where throat culture is slow and beset by a number of factors which reduce its accuracy. Polymerase chain reaction methods have been deve loped for many respiratory pathogens, including Mycoplasma pneumoniae, Chlamydia pneumoniae and Mycobacterium tuberculosis, and are likely t o play an increasingly important part in diagnosis, In bacterial menin gitis culture is still the gold standard and molecular techniques have not yet been developed to the point where they can be used in routine diagnosis, Nucleic acid techniques are likely to be very valuable in the diagnosis of streptococcal pharyngitis and viral central nervous s ystem infections in the near future.