Microbiological sputum testing investigates lower respiratory tract infections, including pneumonia.
More information
Common pathogens of acute pneumonia include Streptococcus pneumoniae, Staphylococcus aureus, Haemophilus influenzae, Pseudomonas aeruginosa, and various members of the Enterobacteriaceae family (Escherichia coli, Klebsiella, Enterobacter). Usually, the individual's history, physical examination, and plain chest radiograph are sufficient to diagnose pneumonia and initiate appropriate antimicrobial therapy.
The sensitivity and specificity of sputum cultures are generally considered low (< 50%). The specificity of cultures can be improved by appropriately collecting sputum from the lower respiratory tract and avoiding contamination from the mouth and pharynx.
This specific sputum microbiological test does not detect specific pathogens that cause lower respiratory tract infections and require special procedures. The microorganisms that are not tested are:
- Mycobacteria (Mycobacerium sp.)
- Legionella sp.
- Pneumonia mycoplasma (Mycoplasma pneumoniae)
- Pneumocystis (Pneumocystis jiroveci)
Pneumonia
Pneumonia can be classified as community-acquired or hospital-acquired (defined as pneumonia that occurs 48 hours or more after admission to the hospital). It can be primary when it appears in a person without any risk factors or secondary. Many conditions are associated with an increased risk of pneumonia. Common risk factors include chronic lung diseases such as chronic obstructive pulmonary disease (COPD), diabetes mellitus, heart or kidney failure, and immunosuppression (congenital or acquired). Reduced level of consciousness and lack of cough reflex are risk factors for aspiration pneumonia. Recent viral respiratory infections, especially influenza, are also risk factors. Specific clinical signs and laboratory markers can be used to assess the severity of pneumonia.
The etiology of pneumonia varies depending on whether it is community-acquired or hospital-acquired and the presence of certain risk factors. Many microorganisms that colonize the upper respiratory tract have been implicated as causes of pneumonia. Previous antibiotic therapy and hospitalization affect the flora, increasing the number of aerobic Gram-negative microorganisms. These factors affect the sensitivity and specificity of sputum culture as a diagnostic test, and the results should always be interpreted in light of the clinical information.
Important Note
Laboratory test results are the most critical parameter for diagnosing and monitoring all pathological conditions. Between 70 to 80% of diagnostic decisions are based on laboratory tests. Correctly interpreting laboratory results allows a doctor to distinguish "healthy" from "diseased."
Laboratory test results should not be interpreted from the numerical result of a single analysis. Test results should be analyzed based on each case and family history, clinical findings, and the results of other laboratory tests and information. Your physician should explain the importance of your test results.
At Diagnostiki Athinon, we answer any questions you may have about the test you perform in our laboratory and contact your doctor to ensure you receive the best possible medical care.
