What Is a Blood Test? A blood test is when a sample of blood is taken from the body to be tested in a lab. Doctors order blood tests to check things such as the levels of glucose, hemoglobin, or white blood cells. This can help them detect problems like a disease or medical condition. Sometimes, blood tests can help them see how well an organ (such as the liver or kidneys) is working. What Is a Lead Test? A lead test measures how much lead is in the blood. Lead is a metal that is found in the environment and in many consumer products. Most people have a small amount of lead in their blood from these exposures. But higher levels of lead can lead to problems in children, such as learning disabilities, behavior problems, and anemia. Very high levels can cause serious problems, such as seizures or a coma. Why Are Lead Tests Done? A lead test may be done if a child is at risk for a high lead level. For example, kids who live in older homes or in communities with many older homes are at risk for high lead levels. How Should We Prepare for a Lead Test? Your child should be able to eat and drink normally unless also getting other tests that require fasting beforehand. Tell your doctor about any medicines your child takes because some drugs might affect the test results. Wearing a T-shirt or short-sleeved shirt for the test can make things easier for your child, and you also can bring along a toy or book as a distraction. How Is a Lead Test Done? Most blood tests take a small amount of blood from a vein. To do that, a health professional will: clean the skin put an elastic band (tourniquet) above the area to get the veins to swell with blood insert a needle into a vein (usually in the arm inside of the elbow or on the back of the hand) pull the blood sample into a vial or syringe take off the elastic band and remove the needle from the vein Lead is sometimes tested with a "fingerstick" test. The health professional will clean your child's finger, then prick the tip of it with a tiny needle (or lancet) to collect the blood. In babies, blood draws are sometimes done as a "heel stick collection." After cleaning the area, the health professional will prick your baby's heel with a tiny needle (or lancet) to collect a small sample of blood. Collecting a sample of blood is only temporarily uncomfortable and can feel like a quick pinprick. Can I Stay With My Child During a Lead Test? Parents usually can stay with their child during a blood test. Encourage your child to relax and stay still because tensing muscles can make it harder to draw blood. Your child might want to look away when the needle is inserted and the blood is collected. Help your child to relax by taking slow deep breaths or singing a favorite song. How Long Does a Lead Test Take? Most blood tests take just a few minutes. Occasionally, it can be hard to find a vein, so the health professional may need to try more than once. What Happens After a Lead Test? The health professional will remove the elastic band and the needle and cover the area with cotton or a bandage to stop the bleeding. Afterward, there may be some mild bruising, which should go away in a few days. When Are Lead Test Results Ready? Blood samples are processed by a machine, and it may take a few hours to a day for the results to be available. If the test results show signs of a problem, the doctor might order other tests to figure out what the problem is and how to treat it. Are There Any Risks From Lead Tests? A lead test is a safe procedure with minimal risks. Some kids might feel faint or lightheaded from the test. A few kids and teens have a strong fear of needles. If your child is anxious, talk with the doctor before the test about ways to make the procedure easier. A small bruise or mild soreness around the blood test site is common and can last for a few days. Get medical care for your child if the discomfort gets worse or lasts longer. If you have questions about the lead test, speak with your doctor or the health professional doing the blood draw. Back to Articles Related Articles Lead Poisoning Long-term exposure to lead can cause serious health problems, particularly in young kids, so it's important to find out whether your child might be at risk for lead exposure. Read More Can Lead Affect My Unborn Baby? Find out what the experts have to say. Read More Getting a Blood Test (Video) A blood test might sound scary, but it usually takes less than a minute. Watch what happens in this video for kids. Read More Blood Test (Video) These videos show what's involved in getting a blood test and what it's like to be the person taking the blood sample. Read More Auditory Processing Disorder Kids with APD can't understand what they hear in the same way other kids do. That's because their ears and brain don't fully coordinate. But early diagnosis and a variety of strategies can help them. Read More Pica Some young kids have the eating disorder pica, which is characterized by cravings to eat nonfood items. Read More Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor. © 1995-2021 KidsHealth®. All rights reserved. Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.