Diagnosis

Tests Done Before Surgery

Choose a preferred language

Many surgeons order routine lab tests before you are admitted to the hospital or before certain outpatient procedures. The tests help find possible problems that might complicate surgery if not found and treated early. Some of the most common tests done before surgery include:

  • Chest X-rays. X-rays can help diagnose causes of shortness of breath, chest pain, cough, and certain fevers. They can also help diagnose heart and lung problems.

  • Electrocardiogram (ECG). This test records the electrical activity of the heart. It shows abnormal rhythms (arrhythmias); finds heart muscle damage; and helps find the cause of chest pain, fluttering heartbeats (palpitations), and heart murmurs.

  • Urinalysis. This test can help diagnose kidney and bladder infections and diabetes. Certain types of urinalyses can also find illegal drugs in the body.

  • White blood count. This test can help diagnose certain fevers and infections. It can also find out if you're using medicines that affect white blood counts.

  • Pregnancy testing. This test can help find out if you're pregnant. Pregnancy changes the way surgical patients are managed. So knowing this information helps keep you and your baby safe.

You may also need one or more of these blood tests before surgery:

  • Glucose. This test measures your blood sugar levels.

  • Electrolytes. This test measures the amount of potassium, sodium, and other electrolytes in your blood. These chemicals help regulate heart rhythms and other body functions.

  • Renal function studies. This test measures blood urea nitrogen (BUN) and creatinine to see how well the kidneys are functioning.

  • Complete blood count (CBC). This test checks for a low number of red blood cells (anemia), a low platelet count, and infection.

  • Coagulation studies (PT/PTT). These tests find out how well your blood clots.

Talk with your health care provider if you have questions or concerns about any of the tests you're taking.

Featured in

Online Medical Reviewer: Jonas DeMuro MD

Online Medical Reviewer: Raymond Turley Jr PA-C

Online Medical Reviewer: Tara Novick BSN MSN

Date Last Reviewed: 01/01/2025

© 2000-2026 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.

Find a Provider

View Our Directory

Find a Location

View Our Practices
Related Articles
Read article
Surgery
Be Involved in Your Health Care: When You’re Having Surgery

It’s normal to feel worried or even a little scared if you are scheduled for surgery. Know that your doctors will do all they can to take good care of you. As a patient, you can help your health care team keep you safe. Being involved means speaking up, asking questions, and knowing your role.

Read article
Surgery
Types of Anesthesia and Your Anesthesia Care Provider

During surgery, you will be given some form of anesthesia - medicine administered for the relief of pain and sensation during surgery. The type and dosage of anesthesia is determined by the anesthesiologist.

Read article
Heart Health
After Minimally Invasive Heart Surgery: At Home

Learn how to care for yourself at home after you have minimally invasive heart surgery. Contact your health care provider if you have questions.

Read article
Digestive Health
After Gallbladder Surgery

Here's what you need to know about caring for yourself after gallbladder surgery.