Emphysema (cont.)

Medical Author:
Medical Editor:

Exams and tests

Oximetry

Oximetry is a non-invasive test, in which a sensor is taped or clipped onto a finger or earlobe to measure the percentage of red blood cells that have oxygen. This value is usually greater than 92%. Results less than 90% may signal the need for supplemental oxygen for home use.

Blood Tests

A complete blood cell count (CBC) may be performed to check for an increase in the number of red blood cells. In response to lower blood oxygen concentrations, the body manufactures more red blood cells to try to deliver as much oxygen as possible to cells.

Alpha-1 antitrypsin levels may be measured to look for the genetic form of emphysema.

An arterial blood gas test will measure the amount of oxygen and carbon dioxide in the blood and combined with other measurements can help the healthcare provider decide whether the body has been able to adapt to the lower oxygen concentrations in the body. In some laboratories, the arterial blood gas result will include a carbon monoxide percentage, most often found in the body because of smoking. For each hemoglobin molecule that has carbon monoxide attached, there is one less available that can carry oxygen.

The arterial blood gas can also give parameters to establish the diagnosis of chronic respiratory failure. The diagnosis of chronic respiratory can be made when the measured oxygen level drops below 60 mmHg (millimeters of mercury) and the carbon dioxide level rises above 50 mm Hg, the diagnosis of chronic respiratory failure can be made.

Radiology

A plain chest X-ray may show lungs that have become too inflated and have lost normal lung markings, consistent with destruction of alveoli and lung tissue.

A CT scan can reveal more detail regarding the amount of lung destruction but is not a normal part of the evaluation of patients with emphysema.

Pulmonary Function Tests

Pulmonary function tests or spirometry can measure the air flow into and out of the lungs and be used to predict the severity of emphysema. By blowing into a machine, the amount of air that is moved and how quickly it moves can be calculated and provides information about lung damage. Results are compared to a "normal" person of the same age, sex, and size.

Some measurements include:

  • FVC (forced vital capacity): the amount of air that can be forcibly exhaled after the largest breath possible.
  • FEV1 (forced expiratory volume in 1 second): the amount of air that is forcibly exhaled in 1 second. Even though total air exhalation may be less affected, as the lung loses its elasticity, it takes longer for the air to get out and FEV1 becomes a good marker for disease severity.
  • FEV (forced expiratory volume): can be measured throughout the exhalation cycle often at 25%, 50%, and 75% to help measure function of different sized bronchi and bronchioles.
  • PEF (peak expiratory flow): maximal speed of air during exhalation.
  • DLCO (diffusion capacity): measures how much carbon monoxide can be inhaled and absorbed into the bloodstream within a period of time. A small amount of tracer carbon monoxide is inhaled and then quickly exhaled. The amount of carbon monoxide in the exhaled air is measured and determines how well the lungs work in absorbing the gas. This helps determine and measure lung function.
Medically Reviewed by a Doctor on 11/14/2013

Patient Comments

Viewers share their comments

Emphysema - Describe Your Experience Question: Please describe your experience with emphysema.
Emphysema - Symptoms Question: What were the symptoms of your emphysema?
Emphysema - Causes and Risks Question: If known, what was the cause of your emphysema?
Emphysema - Diagnosis Question: What kinds of tests and exams did you have that led to a diagnosis of emphysema?
Emphysema - Treatment Question: Please describe the treatments, therapies, and medications you've received for emphysema.
Emphysema - Smoking Question: Are/were you a smoker prior to your emphysema diagnosis? If you've stopped, what worked for you?
Emphysema - Rehabilitation Question: Please share suggestions and tips for exercising and rehabilitating to control your emphysema.

STAY INFORMED

Get the Latest health and medical information delivered direct to your inbox!