Lung Diseases

Tests

Tests can help doctors to choose the best treatments by finding what the problem is. Tests can look at the structure of the lungs (e.g. X-ray), how well the lungs are working (e.g. blood gases), or look straight for the problem (bacterial cultures).

Laboratory Tests:

• Blood gases – an arterial blood sample is collected to evaluate blood acidity, oxygen and carbon dioxide
• FBC (Full Blood Count) – to look for signs of infection or for anaemia (which causes shortness of breath)
• D-dimer – To look for signs of clotting which might suggest a pulmonary embolism
• Cystic Fibrosis Tests (CF Gene Mutation Testing, Sweat chloride, Immunoreactive trypsin (IRT)) – to look for the genetic changes causing cystic fibrosis, and to diagnose the condition
• Alpha-1 antitrypsin – to determine if a patient lacks alpha-1 antitrypsin
• Sputum culture and sensitivities – to grow infectious bacteria and test which antibiotics work against them
• AFB smear and culture – to diagnose tuberculosis and nontuberculous mycobacteria (NTM)
• Blood cultures –to diagnose bacteria and sometimes yeast infections that have spread into the blood
• Influenza tests – not needed normally as doctors can diagnose flu from your symptoms
• Lung Biopsy – a sample of tissue from the lung which can be examined under the microscope for diseases such as cancer
• Sputum cytology – to look for cells with abnormal changes that might show cancer
• Drug screen—to detect drugs in overdoses that lead to breathing difficulties

Lung Function Tests (Pulmonary Function Tests, PFT)

A few of the more common tests are listed below.For more complete information visit the website for John Hopkins Medicine, Pulmonary Function Laboratory 

• Spirometry – measures the amount and rate of air as a patient blows out through a tube.  It looks for narrowed or obstructed airways.
• Peak Flow Meter – measures the rate of exhalation.  It can be used at home by patients with asthma to help monitor their condition.
• Lung Volume – the quantity of air a person takes into their lungs and how much is left in the lungs after exhalation. Helps test the elasticity of the lungs, the movement of the rib cage, and the strength of the muscles associated with respiration.
• Diffusing Capacity Measurement – assesses the transfer of oxygen from the lung air sacs to the bloodstream by evaluating how much carbon monoxide is absorbed when a small quantity is inhaled (not enough to harm).

Imaging studies

• Chest x-ray – to look at lung structure and chest cavity
• CT (Computed Tomography) scan – a more detailed evaluation of lung structure
• MRI (Magnetic Resonance Imaging) – detailed pictures of organs and vessels in the chest
• Ultrasound – used to detect fluid between the pleural membranes
• Nuclear lung scanning –  used to help detect pulmonary embolism and rarely, to evaluate the effectiveness of lung cancer treatment
• PET (Positron Emission Tomography) scans – used to help diagnose lung cancer.

Other tests

• Electrocardiogram (ECG) – to look at heart rhythm, to determine if heart disease may be affecting breathing
• Sleep studies – usually performed at special sleep centres to determine whether a person is breathing normally during sleep