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 look for 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 an ESR Test?
An ESR test measures how quickly red blood cells settle to the bottle of a test
tube. Inflammation (swelling and irritation) or infection can lead to extra proteins
in the blood, which can make the red blood cells settle faster. When this happens,
the ESR is higher.
Why Are ESR Tests Done?
An ESR test may be done if someone has signs of inflammation or infection. ESR
tests are used to follow activity levels of conditions such as inflammatory
bowel disease (IBD), arthritis,
and lupus. ESR tests are
also used to follow how well treatment for inflammation or infection is working.
How Should I Prepare for an ESR Test?
You should be able to eat and drink normally unless 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.
How Is an ESR 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
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 backward, doing some
breathing exercises, thinking of a place that makes you happy, or listening to your
favorite music.
How Long Does an ESR 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 an ESR 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 ESR 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 ESR Tests?
An ESR 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 ESR test, speak with your doctor or the health
professional doing the blood draw.
