In this section
Blood tests to evaluate heart disease
Children with congenital (present at birth) heart disease may have blood tests done to help the physician evaluate their illness, or to help monitor their health after surgery. These tests may include the following:
- Complete blood count - a measurement of size, number, and maturity of different blood cells in a specific volume of blood. Red blood cells are important because they carry oxygen through the bloodstream to the organs and cells of the body. Having too few red blood cells can make a child feel tired, and having too many red blood cells may also indicate a problem. For example, children with cyanotic congenital heart disease may have high numbers of red blood cells in the bloodstream, in an effort by the body to provide enough oxygen to the organs. White blood cells multiply when inflammation or infection is present.
- Electrolytes - minerals in the bloodstream such as sodium, potassium, calcium, and magnesium (that are important for the proper function of organs) may be measured. Electrolytes may be out of balance when a child is taking diuretics.
- Total protein and albumin - these tests can help evaluate a child's nutritional status.
- Prothrombin time (PT), partial thromboplastin time (PTT), and international normalized ratio (INR) - tests done to evaluate the effectiveness of anticoagulant drugs (also known as blood thinners) taken for various heart problems, including artificial valve replacement and irregular heart rhythms.
- Blood gas - a blood sample taken from an artery that measures the amounts of oxygen and carbon dioxide in the bloodstream, as well as the acidity or pH of the blood.
- Pulse oximetry - an oximeter is a small machine that measures the amount of oxygen in the blood. To obtain this measurement, a small sensor (similar to an adhesive bandage) is taped onto a finger or toe. When the machine is on, a small red light can be seen in the sensor. The sensor is painless and the red light does not get hot.
Depending on the results of the blood tests, additional tests or procedures may be scheduled to gather further diagnostic information.
We believe patient families have a right to know what level of care we provide. Review our quality and outcomes reports.
Among the nation's best
U.S. News & World Report has once again ranked the Herma Heart Institute at Children's Wisconsin among the top programs in the nation for pediatric cardiology and heart surgery. This ranking reflects the excellent outcomes and care we provide for even the most complex heart conditions. Families travel from across the country, and even around the world, to receive care from our specialists who are experienced in treating congenital heart disease from before birth and into adulthood.Read the Report