There has been limited progress in the area of early detection of lung cancer. Routine chest x-rays, sputum cell analysis and examination of bronchial passages in high-risk individuals have not shown much success in detecting early-stage lung cancer and improving the chances of survival. Surgery and lung biopsy presents high risks and, therefore, lung cancer screening is not usually advised.

Currently, there is a large scale test being conducted regarding lung cancer screening. The National Lung Screening Trial (NLST) utilizes an x-ray test known as a spiral CT scan in smokers and former smokers in an attempt to detect early lung cancers. It is not yet known if this method will be effective in detecting cancer early enough to save lives. Research continues to evaluate other screening tests to determine their effectiveness in detecting early stage lung cancer and improved survival from the disease.

If lung cancer is suspected, there are number of tests that will be conducted to diagnose the disease. A physician will first obtain a medical history, including smoking habits, environmental factors and family history of smoking. A physical examination will be completed with emphasis on breathing function.

Other tests will be conducted to determine the location, type and stage of the lung cancer. Staging is the process of determining if and the extent that the cancer has spread in the body. Common tests for lung cancer include:

• Blood and urine tests. These tests are taken to determine chemical or hormonal imbalance that may indicate disease in the organs. For instance, abnormal calcium levels or alkaline phosphatase in the blood can be detected, indicating metastasis to the bones.
  
  
• Sputum sample. A sample of phlegm is taken and tested for microscopic examination. This test is used to detect squamous cell carcinoma.

Diagnostic imaging tests include:

• CAT scan. Images are taken of the body from different angles with specialized x-rays and computer technology. CAT scan can be used to locate tumors in the body, such as growths in the lungs.  In some cases, a contrast medium (dye) can be injected into the patient to help highlight abnormalities.
  
  
• Magnetic resonance imaging (MRI). Magnetic and radio waves are used to create detailed three-dimensional images of internal organs to locate tumors.

• X-rays. A chest x-ray is taken to show if there are masses in the organs and bones in the chest cavity. However, chest x-rays often miss early-stage lung cancer in comparison to CAT scans.
  
  
• Radionuclide scanning. This scan is used to view the spread of cancer to other organs such as the liver. A radioactive substance is swallowed or injected. The scanner images the radioactivity of the organs to show any tumor growth.
  
  
• Video-assisted thoracoscopic surgery (VATS). A thin, lighted tube is connected to a video camera and monitor. The space between the lungs and the chest wall is viewed for tumors. Biopsies can be taken of the tumor, the lymph nodes or fluid.
  
  
• Positron emission tomography (PET) scan. A radioactive sugar is injected into the bloodstream and is rapidly absorbed by the cancer cells making them detectable to a camera that creates an image of the tumors.This test is often used to determine if and where the cancer has metastasized.
   
• Bone scan. Radioactive material injected into the bloodstream collects in the bones and images are taken by scanner. The images detect cancer cells in the bones.

Other tests include:

• Bronchoscopy. A bronchoscope is placed through the mouth, down the esophagus and into the breathing passages to look for tumors or blockages. Samples of tissue may be taken in a biopsy for analysis. A biopsy is a definitive test to determine the presence and type of a cancer.
  
  
• Mediastinoscopy. After the patient undergoes general anesthesia, lighted instrument is placed through an incision in the neck and used to view the inside of the chest cavity. The mediastinum (center of the chest between the lungs) and nearby lymph nodes are viewed for tumors. A biopsy may also be taken.
  
  
• Anterior mediastinotomy (Chamberlain procedure). A lighted instrument is placed through a surgical incision in the chest and used to view the inside of the chest cavity. The mediastinum (center of the chest) and nearby lymph nodes are viewed for tumors. A biopsy may be taken during the procedure.
  
  
• Thoracentesis. After the skin is numbed, a needle is inserted between the ribs to remove fluid around the lungs to observe for cancer cells.