Sputum is matter that is expectorated from the respiratory tract, such as mucus or phlegm, mixed with saliva, which can then be spat from the mouth. It is usually associated with air passages in diseased lungs, bronchi, or upper respiratory tract. It can be found to contain blood if in a chronic cough possibly from bad cases of tuberculosis.
A sputum sample is the name given to the mucus that is coughed up from the lower airways. It is usually used for microbiological investigations of respiratory infections.
Microbiological sputum samples are usually used to look for infections by Moraxella catarrhalis, Mycobacterium tuberculosis, Streptococcus pneumoniae and Haemophilus influenzae. Other pathogens can also be found.
Purulent Sputum is that containing, or consisting of, pus.
Sputum can be: