A C-reactive protein (CRP) blood test is used to identify inflammation or infection in the body.
C-reactive protein is released into the blood by the liver shortly after the start of an infection or inflammation. CRP is an early indicator of these problems and its levels can rise quickly.
Doctors may order the C-reactive protein test if symptoms suggest any kind of inflammation, particularly related to inflammatory bowel disease (IBD), arthritis flare-ups, or an autoimmune disorder such as rheumatoid arthritis or lupus.
It may also be used to detect infections in vulnerable patients, such as those who've just had surgery or newborn babies. The CRP test also may help determine whether treatment for any of these conditions is working, because CRP levels drop quickly as inflammation subsides.
No special preparations are needed for this test. Make sure to tell your doctor about any medications your child is taking because certain drugs might alter the test results.
On the day of the test, having your child wear a T-shirt or short-sleeved shirt can make things easier for your child and the technician who will be drawing the blood.
A health professional will usually draw the blood from a vein. For an infant, the blood may be obtained by puncturing the heel with a small needle (lancet). If the blood is being drawn from a vein, the skin surface is cleaned with antiseptic, and an elastic band (tourniquet) is placed around the upper arm to apply pressure and cause the veins to swell with blood. A needle is inserted into a vein (usually in the arm inside of the elbow or on the back of the hand) and blood is withdrawn and collected in a vial or syringe.
After the procedure, the elastic band is removed. Once the blood has been collected, the needle is removed and the area is covered with cotton or a bandage to stop the bleeding. Collecting blood for this test will only take a few minutes.
Either method (heel or vein withdrawal) of collecting a sample of blood is only temporarily uncomfortable and can feel like a quick pinprick. Afterward, there may be some mild bruising, which should go away in a few days.
The blood sample will be processed by a machine. The results are commonly available after a few hours or the next day.
Generally, an elevated CRP level indicates an infection or inflammation somewhere in the body. But the CRP alone can't tell doctors where the problem is or what's causing it, so further testing may be necessary.
The C-reactive protein test is considered a safe procedure. However, as with many medical tests, some problems can occur with having blood drawn, such as:
Having a blood test is relatively painless. Still, many kids are afraid of needles. Explaining the test in terms your child can understand might help ease some of the fear.
Allow your child to ask the technician any questions he or she might have. Tell your child to try to relax and stay still during the procedure, as tensing muscles and moving can make it harder and more painful to draw blood. It also may help if your child looks away when the needle is being inserted into the skin.
If you have questions about the C-reactive protein test, speak with your doctor.
Reviewed by: Yamini Durani, MD
Date reviewed: July 2014
|American Medical Association (AMA) The AMA has made a commitment to medicine by making doctors more accessible to their patients. Contact the AMA at: American Medical Association|
515 N. State St.
Chicago, IL 60610
|American Academy of Pediatrics (AAP) The AAP is committed to the health and well-being of infants, adolescents, and young adults. The website offers news articles and tips on health for families.|
|Arthritis Foundation The mission of this group is to support research to find the cure for and prevention of arthritis and to improve the quality of life for those affected by arthritis.|
|Lupus Foundation of America The mission of the Lupus Foundation of America is to educate and support those affected by lupus and find a cure. Call (800) 558-0121 for information.|
|North American Society for Pediatric Gastroenterology, Hepatology and Nutrition (NASPGHAN) NASPGHAN works to help children and adolescents with digestive disorders.|
|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.|
|Inflammatory Bowel Disease Inflammatory bowel disease (IBD) refers to two chronic diseases that cause intestinal inflammation: ulcerative colitis and Crohn's disease. Although they have features in common, there are some important differences.|
|Blood Test: Erythrocyte Sedimentation Rate (ESR) An erythrocyte sedimentation rate test (ESR) detects inflammation that may be caused by infection, some cancers, and certain autoimmune diseases.|
|Arthritis Kids can get a kind of arthritis that causes joint pain. Find out more in this article for kids.|
|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.|
|Life With Lupus Some people have an autoimmune disorder called lupus. Find out more in this article for kids.|
|Living With Lupus Lupus is known as an autoimmune disease in which a person's immune system mistakenly works against the body's own tissues.|
|Lupus Lupus is a disease that affects the immune system. Learn how lupus is treated, signs and symptoms, how to support a friend who has it, and 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.|
|Helping Kids Deal With Injections and Blood Tests Blood tests and insulin injections can be a challenge for kids with diabetes and their parents. Here are some strategies for coping with these necessary procedures.|
|Juvenile Idiopathic Arthritis Juvenile idiopathic arthritis (also called juvenile rheumatoid arthritis) affects some 50,000 kids in the United States. Learn more.|
|Juvenile Idiopathic Arthritis (JIA) Learn about juvenile idiopathic arthritis, a specific kind of arthritis that usually occurs in kids and teens under age 17.|
|Blood Test: Alanine Aminotransferase (ALT, or SGPT) An alanine aminotransferase (ALT) blood test is often part of an initial screening for liver disease.|
|Blood Test: Bilirubin Doctors may order bilirubin blood tests for infants or older kids if they see signs of the skin taking on the yellow discoloration known as jaundice.|
|Blood Test: Erythrocyte Sedimentation Rate This test measures the speed at which red blood cells fall to the bottom of an upright glass test tube. Find out why doctors do it and what's involved for teens.|
What to expect when coming to Akron Children's
For healthcare providers and nurses
Residency & Fellowships, Medical Students, Nursing and Allied Health
For prospective employees and career-seekers
Our online community that provides inspirational stories and helpful information.