What diagnostic test is primarily used for confirming pneumonia?

The primary diagnostic test for confirming pneumonia is a chest x-ray showing lung infiltrates. This imaging technique is highly effective in visualizing the presence of consolidation, which typically indicates pneumonia in the lungs. The chest x-ray can reveal areas where the lung appears cloudy or opaque, signaling the accumulation of fluid or inflammatory cells, which is characteristic of pneumonia.

While a CT scan of the thorax can provide more detailed images and better anatomical clarity, it is not routinely used as the first-line diagnostic tool for pneumonia. It is more commonly reserved for complex cases or when other complications are suspected.

A complete blood count (CBC) is useful for assessing the patient's overall health, identifying signs of infection, and determining the presence of an inflammatory response. However, it does not specifically confirm pneumonia.

Bronchoscopy allows for direct visualization of the airways and can be used to obtain samples for microbiological testing, especially in complicated cases or when the diagnosis is uncertain. However, it is an invasive procedure and not a primary diagnostic method for pneumonia.

Thus, the chest x-ray remains the standard and most widely utilized initial test for the diagnosis of pneumonia due to its accessibility, speed, and effectiveness in detecting lung infiltrates.