A sputum culture may be performed, particularly if the sputum is green or has blood in it, to determine whether a bacterial infection is present and to identify the disease-causing organism so that an appropriate antibiotic can be selected.
Laboratory diagnostic tests may include staining sputum samples on a glass slide and looking at the stained specimen under a microscope to determine if white cells, red cells, or bacteria are present.
Tuberculosis is nearly always diagnosed by tuberculin skin tests, although one can also be diagnosed by chest x rays and analysis of sputum (matter from the respiratory tract) smears and cultures.
Identification of the specific type of bacteria may require culturing the sputum, a microbiological technique that identifies disease-causing bacterial organisms in infected material.
A small sample of sputum will be streaked on a special plate filled with medium that allows the specific organism to be grown in the laboratory under certain conditions.
Bluish skin (cyanosis), coughing, vomiting, and frothy pink sputum (material expelled from the respiratory tract by coughing) are often observed.
It is found in the buboes in ordinary cases, in the blood in the so-called " septicaemic " cases, and in the sputum of pneumonic cases.
In cases where the disease is odourless the larvae are attacked after the cells are sealed over, and just before they change to pupae, when they become slimy, sputum-like masses, difficult to remove from the cells.
- Phagocytic cells (in sputum) FIG.
Thus if a little diphtheritic sputum were coughed into a person's eye, or some blood containing anthrax bacilli were to touch a raw spot upon the hand, the removal of microbes in either case by washing with simple water might be regarded as a means of passive defence, whilst washing them away with an antiseptic lotion might be regarded as active defence, because the antiseptic would tend not only to remove but to destroy the microbes.