Why would my child need a lab test?

A laboratory (lab) test is a procedure in which a health care provider takes a sample of blood, urine, or other body fluid or tissue. The tests can provide important information about your child's health. They may be used to diagnose, screen for, or monitor diseases and conditions. Lab tests can also be used to check the health of organs and body systems.

But lab tests can be scary, especially for children. Fortunately, children don't need to be tested as often as adults. But if your child does need testing, you can take steps to help them feel less scared and anxious. Preparing in advance may also help keep your child calm and less likely to resist the procedure.

How do I prepare my child for a lab test?

Here are some simple steps that may make your child feel more at ease before and during a lab test.

• Explain what will happen. Tell your child why the test is needed and how the sample will be collected. Use language and terms based on your child's age. Assure your child you will be with them or nearby the whole time. Let them know that adults sometimes get nervous about having lab tests, too.
• Be honest but reassuring. Don't tell your child the test won't hurt; it may actually be painful. Instead, say that the test may hurt or pinch a bit, but the pain will go away quickly.
• Practice the test at home. Younger children can practice doing the test on a stuffed animal or doll.
• Practice deep breathing and other comforting activities with your child. These may include thinking happy thoughts and counting slowly from one to ten.
• Schedule the test at the right time. Try to schedule the test for a time when your child is less likely to be tired or hungry. If your child is getting a blood test, eating beforehand will lessen the chance of lightheadedness. But if your child needs a test that requires fasting (not eating or drinking), it's best to schedule the test for first thing in the morning. You should also bring a snack for afterward.
• Offer plenty of water. If the test doesn't require limiting or avoiding fluids, encourage your child to drink lots of water the day before and the morning of the test. For a blood test, it can make it easier to draw blood because it puts more fluid in the veins. For a urine test, it can make it easier to urinate when the sample is needed.
• Offer a distraction. Bring along a favorite toy, game, or book to help distract your child before and during the test.
• Provide physical comfort. If the provider says it's OK, hold your child's hand or provide other physical contact during the test. If your baby needs a test, comfort them with gentle physical contact and use a calm, quiet voice. If you are allowed, hold your baby during the test. If not, stand where your baby can see your face.
• Plan a reward for afterward. Offer your child a treat or make a plan to do something fun together after the test. Thinking about a reward may help distract your child and encourage cooperation during the procedure.

Specific preparations and tips will depend on your child's age and personality, as well as the type of test being done.

What happens to my child during a lab test?

Common lab tests for children include blood tests, urine tests, swab tests, and throat cultures.

Blood tests are used to test for many different diseases and conditions.

During a blood test, a sample will be taken from a vein in the arm, a fingertip, or a heel.

• If done on a vein, a health care professional will take a sample, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial.
• A fingertip blood test is done by pricking your child's fingertip.
• Heel stick tests are used for newborn screenings, a test given shortly after birth to almost every baby born in the United States. These screenings are used to help diagnose a variety of serious health conditions. During a heel stick test, a provider will clean your baby's heel with alcohol and poke the heel with a small needle.

Encourage your child to look at you during a blood test rather than at the person drawing the blood. You should also provide physical comfort and distraction.

Urine tests are done to check for different diseases and for infections of the urinary tract. During a urine test, your child will need to provide a urine sample in a special cup. Unless your child has an infection or a rash, a urine test is not painful. But it can be stressful. The following tips may help:

• Talk to your child's provider to find out if a "clean catch" method will be needed. For a clean catch urine sample, your child will need to give a urine sample for the test. A health care professional may give them a cleansing wipe, a small container, and instructions for how to use the "clean catch" method to collect their urine sample. Explain to your child that it is important to follow these instructions so that germs from their skin, toilet paper, or hair don't get into the sample. Depending on your child's age, you may need to help them:
  • Wash their hands with soap and water and dry them.
  • Open the container without touching the inside.
  • Clean their genital area with a cleansing wipe.
    • For a penis, wipe the entire head (end) of the penis. If they have a foreskin, it will need to be pulled back first.
    • For a vagina, separate the labia (folds of skin around the vagina) and wipe the inner sides from front to back.
  • Ask them to urinate into the toilet for a few seconds and then stop the flow. They should start urinating again, this time into the container. Don't let the container touch their body.
  • Collect at least an ounce or two of urine into the container. The container should have markings to indicate how much urine is needed.
  • They should finish urinating into the toilet.
  • Put the cap on the container and return it as instructed.
• If a clean catch sample is needed, practice at home. Ask your child to let out a bit of urine in the toilet, stop the flow, and start again.
• Encourage your child to drink water before the appointment, but not go to the bathroom. This may make it easier for your child to urinate when it's time to collect the sample.
• Turn on the tap. The sound of running water can help your child begin to urinate.

Nasal swab tests help diagnose different types of respiratory infections. During a swab test, a provider will:

• Gently insert a cotton-tipped swab inside your child's nostril. For some swab tests, a provider may need to insert the swab deeper until it reaches the uppermost part of the nose and throat (the nasopharynx).
• Rotate the swab for 10-15 seconds.
• Remove the swab and insert it into your child's other nostril.
• Swab the second nostril using the same technique.
• Remove the swab.

Swab tests may tickle the throat or cause your child to cough. A swab of the nasopharynx may be uncomfortable and cause a gag reflex when the swab touches the throat. Let your child know beforehand that gagging may happen, but it will be over quickly. It may also help to tell your child that the swab is similar to the cotton swabs you have at home.

Throat cultures are done to check for bacterial infections of the throat, including strep throat. During a throat culture:

• Your child will be asked to tilt their head back and open their mouth as wide as possible.
• Your child's provider will use a tongue depressor to hold down your child's tongue.
• The provider will use a special swab to take a sample from the back of your child's throat and tonsils.

A throat swab isn't painful, but like some swab tests, it can cause gagging. Let your child know what to expect and that any discomfort shouldn't last very long. You may need to hold your child if they are younger to provide comfort and keep them from moving.

Is there anything else I should know about preparing my child for a lab test?

If you have questions or concerns about testing or if your child has special needs, talk to your child's provider. You can work together to discuss the best way to prepare and comfort your child throughout the testing process.

Learn more about laboratory tests, reference ranges, and understanding results.