Once you and your doctor / healthcare professional are used to your
normal state, you will be able to use the BronkoTest Action Plan to help you recognise changes in your symptoms and sputum and to determine what treatment is appropriate.

Exacerbations of COPD are a major cause of poor health, and require
an increase in usual treatment and/or the introduction of new treatments such as a course of steroids or antibiotics (Refs. 1 & 17).

Antibiotic treatment is widely used but often not needed because it is
difficult to be sure when there is an infection with bacteria. Because doctors are cautious and do not want to miss an opportunity to help patients by treating a bacterial infection, antibiotics are often given when they are neither needed nor helpful. When antibiotics are prescribed needlessly, it is becoming more and more common for them to be ineffective when they are needed for later infections. For this reason, a means of determining when a chest infection is caused by bacteria is very valuable.

When faced with an infection caused by bacteria, the body normally responds by using its own natural defences. Antibiotics are needed when these defences fail, and antibiotics can also add to the body's defences to speed recovery from bacterial infections. In the lung it is relatively easy to detect when the natural defence response to bacteria is overrun by assessing the colour of the sputum (phlegm). When there is uncontrolled bacterial infection in the lungs, neutrophils (usually known as white blood cells) get called into the lung in increasing numbers to fight the infection. If you cough up sputum (phlegm), these cells and the bacteria can be seen under a microscope. However that often doesn't help the doctor/healthcare professional decide whether an infection is present because it is difficult to carry out these tests in the clinic. Moreover, smaller but misleading amounts of the cells and bacteria can be present even when there is no infection that needs treating.

A simpler way to find a lung infection due to bacteria is to look at the colour of the sputum. This works because the white blood cells contain a protein called myeloperoxidase which is only seen in white blood cells and which is intensely green in colour. They contain a protein called myeloperoxidase which is only present in white blood cells and is green in colour. Thus as more white blood cells accumulate in the sputum in response to bacteria, their green colour becomes more obvious.

This colour change in sputum indicates how likely it is that bacteria are
present (Fig. 1), as well as how many bacteria are present (Ref. 4).

Sputum colour, or change in sputum colour from usual, can be used to identify who requires antibiotics for treatment of exacerbations (chest colds). If the antibiotic treatment is right, the bacteria are killed. The need for white blood cells then decreases, so they no longer move to the lungs and the colour of the sputum clears. This can be easily detected and monitored by patients (Ref 16).