The principle is quite simple: a thin cotton swab, similar to a cotton swab, is inserted into the patient's throat and gently rubbed - with horizontal, vertical and circular movements - first on the tonsils and then on the mucosa of the posterior pharynx (i.e. the areas in which the microorganisms responsible for pharyngitis generally lurk). This gesture is performed with extreme care, to avoid contact with the other mucous membranes of the oral cavity.
In this way, the throat swab remains impregnated with cells, mucus and exudate and, subsequently, it is analyzed in the laboratory or put in contact with special antibody reagents for a semi-instant diagnosis.
In the classic procedure, which takes two or three days before providing results, the throat swab is sent to the laboratory for culture. In practice, the collected cells are reproduced in a culture medium containing the elements necessary for the growth of microorganisms. ; once a sufficiently large cell population has been obtained, the colonies are used for diagnostic and therapeutic purposes, evaluating their sensitivity to various types of antibiotics (antibiogram).
Thanks to this information the doctor can choose the most effective drug, which ensures the complete eradication of the pathogen avoiding the selection of microorganisms resistant to antibiotics. If, for example, the throat swab shows that pharyngitis has viral origins (as happens in most part of acute episodes) it is absolutely useless, and in many respects harmful, to take antibiotics.
, viruses or fungi.(inflammation of the tonsils) of which an infectious origin is suspected.
This investigation is suggested after observation during the visit or on the basis of the symptoms reported by the patient, especially when the sore throat:
- It tends to recur with a certain frequency;
- It does not resolve spontaneously within a week, as usually occurs for colds typical of the winter period which recognize a viral origin, such as colds, flu and parainfluenza syndromes;
- It is associated with persistent high fever (a sign that suggests a bacterium is involved).
