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 Basic Metabolic Panel (BMP)? The basic metabolic panel (BMP) is a blood test that gives doctors information about the body's fluid balance, levels of electrolytes like sodium and potassium, and how well the kidneys are working. Why Are Basic Metabolic Panels Done? A BMP is done to learn information about the levels of: Glucose, a type of sugar used by the body for energy. High glucose levels may point to diabetes. Electrolytes: Calcium, which plays an important role in how muscles and nerves work. Sodium, potassium, carbon dioxide, and chloride, which help control the body's fluid levels and its acid-base balance. Normal levels of these electrolytes help keep cells in the body working as they should. Blood urea nitrogen (BUN) and creatinine, which are waste products filtered out of the blood by the kidneys. These levels show how well the kidneys are working. How Should We Prepare for a BMP? Your child may be asked to stop eating and drinking for 8 to 12 hours before a BMP. 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 BMP 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 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 BMP? 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. Encourage your child to relax by taking slow deep breaths or singing a favorite song. How Long Does a BMP 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 BMP? 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 BMP 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 BMPs? A basic metabolic panel 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 BMP, speak with your doctor or the health professional doing the blood draw. Back to Articles Related Articles Definition: Hypoglycemia Hypoglycemia occurs when the level of glucose in the blood is lower than it should be. Read More Diabetes Center Our Diabetes Center provides information and advice for teens about treating and living with diabetes. Read More Diabetes Center Does your child have type 1 or type 2 diabetes? Learn how to manage the disease and keep your child healthy. 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 Hypoglycemia When blood glucose levels drop too low, it's called hypoglycemia. Very low blood sugar levels can cause severe symptoms that require immediate treatment. 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 Calcium Milk and other calcium-rich foods help build strong, healthy bones. But most kids and teens don't get enough calcium. Here's how to make sure that yours do. Read More Diabetes Center Diabetes means a problem with insulin, an important hormone in the body. Find out how children with diabetes can stay healthy and do the normal stuff kids like to do. Read More Urine Test: Microalbumin-to-Creatinine Ratio The microalbumin-to-creatinine ratio test is most commonly used to screen for kidney problems in teens with diabetes. It may also be used to monitor kidney function in kids and teens who have a kidney disease. 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Doctors may order this test if they suspect kidney damage, cysts, tumors, kidney stones, or complications from urinary tract infections. Read More Blood Test: Basic Metabolic Panel A basic metabolic panel (BMP) is a group of blood tests that provide doctors with clues about how the body is working. Find out why doctors do this and what's involved for teens. Read More Basic Blood Chemistry Tests Doctors order basic blood chemistry tests to assess a wide range of conditions and the function of organs. 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.