Pre-operative Testing

There are many reasons why children need surgery. No matter what type of surgery or procedure a child will be receiving, we are dedicated to ensuring that our surgeons, nurses and other pediatric-trained specialists have all of the information they need to make the surgical experience a success.

Before surgery, the patient’s caregiver will receive a phone call from a preoperative (“pre-op”) nurse. The nurse will ask the caregiver questions about the child’s health history, home medications and treatments. The nurse will also let the caregiver know what time to arrive and where to park. It is very important that caregivers return any missed called as soon as possible.

Many patients at may need important tests prior to their surgery to make sure we provide the best and safest possible care. Necessary tests and services are determined by the patient’s physician and surgeon based upon the child’s condition, health history and planned surgery and anesthetic. Caregivers with questions about the types of tests needed before surgery should contact the child’s surgeon’s office.

Common tests can include:

Blood Test

Blood tests are used to determine a variety of health concerns and are the most commonly administered preoperative assessments. The most common types of blood tests include a complete blood count (CBC), a blood chemistry panel or basic metabolic panel (BMP), coagulation study and a blood type and screen test. Learn more about CHOC’s laboratory services.

  • The CBC can help detect blood diseases and disorders, such as anemia, infections, clotting problems, blood cancers and immune system disorders.
  • A BMP is a group of tests that measures different chemicals in the blood and gives doctors information about the patient’s muscles (including the heart), bones and organs, such as the kidneys and liver.
  • A coagulation study determines how quickly the patient’s blood clots. This study is important because during some surgeries it is important that the blood not clot as quickly as normal.
  • Blood typing is a laboratory test that identifies a patient’s blood type and allows us to ensure that a patient receives the right type of blood should he or she need a transfusion during surgery.


X-rays are made by using low levels of external radiation to produce images of the body, organs and other internal structures of the body. The rays pass through body structures onto specially treated plates (similar to camera film) and a “negative” type picture is made. The more solid a structure is, the whiter it appears on the film. For this reason, bones appear very white on an x-ray film. The less dense tissue such as muscle, blood, skin, and fat appears darker. The most commonly ordered preoperative x-ray is a chest x-ray. These x-rays are used to make sure there are no problems or issues with the heart and lungs. Learn more about X-rays.


Magnetic resonance imaging, also known as an “MRI,” is a test that uses powerful magnets instead of X-rays to take pictures of body tissues using radio waves. These radio waves are not harmful to tissues, and the procedure is painless. If an MRI is needed before surgery, it is often completed the same day of surgery right before the patient goes to the operating room. Sometimes, children may require sedation for this procedure because they must remain absolutely still. Learn more about MRI.


An electrocardiogram, also known as “EKG” evaluates the conduction system of the heart. Small electrode patches are placed on the chest, wrist and ankles and are connected to a machine that traces the electrical activity of the heart. Learn more about electrocardiograms.