Visit our foundation to give a gift.
View Locations Near Me
Main Campus – Hartford
Connecticut Children’s – Waterbury
Urgent Care – Farmington
Specialty Care Center – Danbury
Connecticut Children’s Surgery Center at Farmington
Specialty Care Center – Fairfield
Search All Locations
Find a doctor
Find A Doctor
Request an Appointment
Amenities and Services
Who’s Who on Care Team
Getting Ready for Surgery
What to Expect—Picture Stories
Pay a Bill
Understanding the Different Fees
Pricing Transparency and Estimates
Raytheon Technologies Family Resource Center
Family Advisory Council
Legal Advocacy: Benefits, Education, Housing
Electronic Health Records
Share Your Story
Pay a Bill
Login to MyChart
Clinical Support Services Referrals
About the Network
Join the Network
Graduate Medical Education
Continuing Medical Education
MOC/Practice Quality Improvement
Educating Practices in the Community (EPIC)
Learning & Performance
Meet our Physician Relations Team
Request Medical Records
Join our Referring Provider Advisory Board
View our Physician Callback Standards
Read & Subscribe to Medical News
Register for Email Updates
Update Your Practice Information
Refer a Patient
Find and Print Health Info
Health Information For Teens
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 find 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.
A phosphorus test measures the amount of phosphorus in the blood. Phosphorus is a mineral that helps in the formation of bones and teeth. It also helps make protein and energy, and helps keep muscles and nerves working the way they should.
A phosphorus test might be done if someone has a medical condition that makes high or low phosphorus levels more likely, such as a kidney problem.
You should be able to eat and drink normally unless you’re also getting other tests that require fasting beforehand. Tell your doctor about any medicines you take because some drugs might affect the test results.
It can help to wear a T shirt or other short-sleeve top on the day of the test to make things faster and easier for the technician who will be drawing the blood.
Usually, the blood is drawn from a vein in your arm — most often on the inside of the elbow, but sometimes on the back of the hand. To do that, a health professional will:
It’s best to try to relax and stay still during the procedure because tensing muscles can make it harder and more painful to draw blood. And if you don’t want to watch the needle being inserted or see the blood collecting, you don’t have to. Look the other way and maybe relax by focusing on saying the alphabet backwards, doing some breathing exercises, thinking of a place that makes you happy, or listening to your favorite music.
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.
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.
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.
A phosphorus test is a safe procedure with minimal risks. Some people might feel faint or lightheaded from the test. A few teens have a strong fear of needles. If you’re 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 if the discomfort gets worse or lasts longer.
If you have questions about the phosphorus test, speak with your doctor or the health professional doing the blood draw.
These videos show what’s involved in getting a blood test and what it’s like to be the person taking the blood sample.
The kidneys perform several functions that are essential to health, the most important of which are to filter blood and produce urine.
Sometimes, the kidneys can’t do their job properly. In teens, kidney disease is usually due to infections, structural issues, glomerulonephritis, or nephrotic syndrome.
A magnesium test looks at levels of the mineral magnesium in a person’s blood. Find out why doctors do this test and what’s involved for teens.
This common blood test helps doctors gather information about a person’s blood cells and how they’re working. Find out why doctors do this test and what’s involved for teens.
Find out about the mysterious, life-sustaining fluid called blood.
Our Diabetes Center provides information and advice for teens about treating and living with diabetes.
Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor.
© 1995-2020 KidsHealth®. All rights reserved.
Images provided by The Nemours Foundation, iStock, Getty Images, Veer, Shutterstock, and Clipart.com.