Common tests in the NICU

Why do babies have tests in the neonatal intensive care unit (NICU)?

Your baby’s healthcare providers in the NICU give your baby medical tests to find out about your baby’s health conditions. Test results help providers know what treatment your baby needs. For example, providers may do a blood test to check your baby for anemia. Anemia is when your baby doesn’t have enough healthy red blood cells to carry oxygen to the rest of their body. Or providers may take an X-ray to check your baby for a lung infection. Your baby’s provider tells you what tests your baby needs and tells you the test results.

Before providers can do certain tests, they need your consent. This means they’ll ask you to read and sign a consent form. When you sign the form, you give them permission to do the test. Sign the form only when you understand what the test is and why your baby needs it. Ask your baby’s providers any questions you have about the test before you sign the form.  

What tests could your baby have in the NICU?

blood test — Tests your baby’s blood for certain health conditions. Blood tests are the most common tests done in the NICU. Test results give providers important information about your baby’s health. They also help providers find possible problems before they become serious.

CAT scan or CT scan — Also called computed tomography scan. A test that takes pictures of the inside of the body. It’s like an X-ray, but it gives a clearer, three-dimensional (3D) view. Your baby goes to the radiology department for the test. Medicine may be given to your baby to help keep them still during the test.

echocardiogram — Also called an echo or a cardiac ultrasound. An ultrasound is used to take pictures of and study the heart. Providers use this test to help find heart problems, including heart defects. A heart defect is a problem with the heart that’s present at birth.

EEG — Also called, electroencephalogram. A test that measures activity in the brain. This is used to detect seizures.

EKG or ECG— Also called electrocardiogram.  A test that records the heart’s electrical activity. An EKG can show how fast your baby’s heart is beating and if the rhythm of the heartbeat is regular.

hearing test — Also called brainstem auditory evoked response test or BAER. This test checks your baby’s hearing. A provider places a tiny earphone in your baby’s ear and puts small sensors on their head. The provider plays sounds through the earphones, and the sensors send information to a machine that measures your baby’s response to the sounds. All babies get this test as part of newborn screening.

MRI— Also called magnetic resonance imaging. A medical test that makes a detailed picture of the inside of your body.

newborn screening test — Checks for serious but rare and mostly treatable conditions at birth. It includes blood, hearing, and heart screening.

ROP exam— Also called retinopathy of prematurity exam or eye exam. Providers use this test most often for babies born before 30 weeks of pregnancy or babies who weigh less than 3 1/3 pounds. An eye doctor (ophthalmologist) checks to see if the blood vessels in your baby’s eyes are developing the right way. If the doctor sees signs of problems, they check your baby’s eyes over time to see if the condition gets better or if it needs treatment.

ultrasound — A test that uses sound waves to take pictures of the inside of the body.

urine test — Tests a baby’s urine for certain health conditions. Urine test results can tell providers a lot about your baby’s overall condition. For example, test results can tell providers if your baby’s getting enough fluid, how your baby’s kidneys are working, and if your baby has an infection. Your baby’s provider inserts a thin tube called a urinary catheter in the opening where urine passes out of your baby’s body to collect the urine.

X-ray — A test that uses small amounts of radiation to take pictures of the inside of the body.

Last reviewed: April 2025