Common NICU Tests

Neonatal Intensive Care Unit (NICU): Tests

The following alphabetized list explains some of the tests and checkups infants might have in NICU hospitals. This information will help you better understand and support your preemie.

And, for more information to help familiarize yourself with the NICU, be sure to click on the related guides that cover staff, equipment, and common problems.

Behavioral exam. A formal assessment of behavior and development, which most infants have at least once during their stay in the NICU. Measurements are made by means of the Neonatal Behavioral Assessment Scale (NBAS), the Assessment of the Premature Infant's Behavior (APIB), or another tool. If possible, try to be present for this evaluation; it's fun to see all the things your baby can do and how he changes and matures over time.

Blood tests. Among the most frequent procedures done in the NICU. The sicker and more unstable the infant, the more often a blood test is done. Blood tests can tell if a baby is anemic or if bilirubin levels are too high, for example. They show whether a baby has low blood sugar (hypoglycemia) or salt or water imbalances, all of which can cause problems if not corrected. Blood tests also can determine whether your baby has an infection and, if so, which antibiotic should be used to treat it. Blood may be drawn from an intravenous or arterial line, from a vein, or from a prick on the baby's heel.

Blood-gas tests. Measurements of the oxygen and carbon dioxide present in your baby's blood. Blood gases are measured frequently in infants with lung and/or heart problems so they may be kept in good balance. Test results indicate whether the ventilator needs to be adjusted or whether additional testing or intervention is required. Blood gases are sampled from an arterial line placed in the wrist or ankle or through the umbilical cord. They can also be sampled from a skin puncture on the child's heel after the heel has been heated, a procedure that may be referred to as a "cap (capillary) gas." The levels of oxygen and carbon dioxide are referred to as pO2 and pCO2. If the infant is very sick, testing is required several times per hour.

Car seat safety. Before your baby goes home, doctors will have to ascertain whether he can be placed in a car seat without compromising his breathing. You'll be asked to bring in your car seat; the baby will be positioned in it and then hooked up to a breathing monitor and oxymeter. If his sitting position creates any problems with breathing, adjustments will have to be made before he goes home.

Computed tomography (CAT scan or CT scan). An advanced form of an X-ray that focuses a beam of energy on the tissue the doctor wants to examine and then uses computers to create a two-dimensional image. This scan is usually done of the brain, but can be used to visualize many body areas. For the test, your baby will be taken to the hospital's radiology department and possibly sedated so he doesn't move.

Echocardiogram. A specialized form of ultrasound examination, used to study the structure and function of the heart. (The term echo can refer to any ultrasound study but is most often used to refer to a heart study.)

Electroencephalogram (EEG). A brain wave test looking for seizures or other irregularities in brain functioning. Small wires are applied to the scalp (they don't hurt), and a recording is made of the brain's electrical activity over a period of time.

Electrocardiogram (ECG, EKG). A recording of the heart's electrical activity. Small wires on the chest and elsewhere on the body, and sometimes in the esophagus, pick up the impulses from different angles to see whether there are any irregularities in the heart rhythm or any unwanted shifts in voltage.

Gestational age evaluation. An assessment of your baby's maturity using physical features such as skin thickness and neurological signs, such as flexibility. These findings are compared with standards to determine how mature your infant is at the time of birth — how long he has been in the uterus. Maternal dates using the date of the start of the last menstrual period are sometimes unknown or inaccurate, so the baby's features help doctors evaluate how his development compares with that of other infants.

Hearing tests. Premature and sick babies are at increased risk of hearing problems. Before your baby goes home, he probably will have a hearing test: either a brainstem auditory evoked response test (BAER) done by an audiologist or an otoacoustic emission test (OAE) done by a nurse or technician. Small sensors taped to your baby's head will relay information to a machine that measures the electrical activity in his brain in response to sound. With a BAER test, tiny earphones are placed in the baby's ears, and sounds are delivered through a range of frequencies (pitches) and loudness levels (decibels). If your baby responds normally, he probably has normal hearing. Repeat testing may be needed at 9 to 12 months, or even sooner if your baby fails one of these tests, or if he is very small or ill at the time of the original testing.

Magnetic resonance imaging (MRI). An imaging technique that can, like a CT scan, produce a detailed picture of tissue that may be difficult to see on an X-ray or ultrasound. MRI may be used to visualize the brain or another part of the body. It gives a more detailed view than a CT scan for most conditions, but requires sedation to keep the baby very still during a noisy and somewhat prolonged procedure. An MRI uses no radiation, but instead employs powerful magnets and computers to create an image. Your baby will be moved to the radiology department for this test.

Newborn screening test. A test performed by pricking a baby's heel to obtain a few drops of blood on a filter paper. Also known as a PKU or NBS test, this procedure checks for serious hereditary disorders. Most states require screening for three to eight disorders. Testing may need repeating in a preterm infant if the first test was done very early, before feeding was established, or if it was done after a blood transfusion.

Temperature measurements. In a preemie, skin temperature, axillary (under-the-arm) temperature, and rectal temperature are likely to be close to one another because the baby is so small. Measurements of oral temperature and ear temperature are not accurate in small infants.

Ultrasound. A procedure using sound waves (rather than X-rays) to create an image of the baby's organs. A small, handheld device called a transducer is rubbed back and forth over the area that the doctor wants to see. An ultrasound examination is painless and can be done during NICU monitoring. An ultrasound (also called a sonogram) of the head is the usual test to diagnose bleeding in the brain. Other organs can be visualized as well. You may hear the pictures referred to as echoes, as in "head echo," "heart echo," or "kidney echo."

Urine tests. Like blood tests, urine tests can tell a great deal about your baby's overall condition. Urine tests can show how well the kidneys are functioning and whether your baby has an infection. Doctors can collect urine by placing a bag-collecting system over the genitals ("bagging"), placing a small tube into the bladder ("cathing"), or using a needle and syringe to draw urine directly out of the bladder (a bladder tap).

Weighing. Your baby will be weighed soon after delivery, and then at least once a day while he is in the NICU. Don't be alarmed if your baby loses some weight after birth or if his weight varies from day to day at first. This is normal, especially for very small babies. When a premature baby starts gaining weight at a steady rate, it is an encouraging sign. Each baby has a weight chart at bedside so doctors can compare his weight with what's expected for his adjusted age. Steady weight gain is an important precursor to hospital discharge. Weight is usually expressed in grams for NICU babies.

X-ray. A diagnostic tool that provides pictures of your baby's lungs and other internal organs. These pictures help the doctor plan treatment and monitor progress. Your baby may require several lung X-rays each day if he has serious breathing problems or if there are concerns about heart function. X-rays are usually done after every breathing tube placement or after any change in the baby's course of treatment.

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