The test is ordered in patients with symptoms of pneumonia
or other respiratory diseases, such as bronchitis.
Sputum collection is done early in the morning. The patient must have eaten at least two hours before the test. It is also essential to brush teeth and rinse mouth well prior to the test. It may be brought up by coughing (expectorated) or it may be or induced with the help of sterile saline or glycerin aerosol. The coughed up sputum is collected into a sterile cup provided by the laboratory.
Two forms of sputum tests are done simultaneously. A small sample of the sputum is taken and a smear is made on a glass slide. It is then stained using Gram stain to identify the bacteria. If the smear shows more number of normal cells then the sample collection has to be repeated and the experiment repeated for correct results. If plenty of WBCs are detected then an infection is indicated and the sample may be considered for culturing.
A sample of the sputum is then grown on a culture dish using appropriate media. This allows the pathogenic bacteria to grow allowing its further identification.
Antimicrobial susceptibility testing also needs carried out to test the susceptibility of the bacteria to antibiotics
. This is necessary to assess the response of these bacteria to certain antibiotics and to ensure the best possible treatment.Physiology : Sputum
or phlegm is the thick mucus that is produced by the lungs. Sputum samples are collected from patients to detect the presence of disease -causing pathogens such as bacteria, virus or fungi.
Sputum samples are studies in patients to detect the presence of bacteria
that may be causing bacterial pneumonia. This condition can be detected as changes in the lungs on X-ray films.
Symptoms of bacterial pneumonia include cough
, breathing difficulty
, muscle and chest pain
, and sometimes even confusion.Normal Range :
If the following bacteria are detected it indicates the possibility of bacterial pneumonia:
• Staphylococcus aureus
• Haemophilus influenzae
• Moraxella catarrhalis
• Klebsiella pneumoniae
• Streptococcus pyogenes
If there is an absence of pathogenic bacteria, the clinical symptoms could be a result of viral infection.