Is a Creatinine Blood Test?
A creatinine blood test measures the level of creatinine in the
blood. Creatinine is a waste product that forms when creatine breaks down.
Creatine is found in your muscle. Creatinine levels in the blood can provide
your doctor with information about how well your kidneys are working.
The kidneys are a pair of fist-sized organs located at the bottom
of the rib cage. One kidney is on each side of the spine. Each kidney has
millions of small blood-filtering units called nephrons. The nephrons constantly
filter blood through a very tiny cluster of blood vessels known as glomeruli. These
structures filter waste products, excess water, and other impurities out of the
blood. The toxins are stored in the bladder and then removed during
Creatinine is one of the substances that your kidneys normally
eliminate from the body. Doctors measure the level of creatinine in the blood
to check kidney function. High levels of creatinine may indicate that your
kidney is damaged and not working properly.
Creatinine blood tests are usually performed along with several
other laboratory tests, including a blood
urea nitrogen (BUN) test and a basic
metabolic panel (BMP) or comprehensive metabolic panel (CMP). These tests
are done during routine physical exams to help diagnose certain diseases and to
check for any problems with your kidney function.
Is a Creatinine Blood Test Done?
Your doctor may order a creatinine blood test to assess your
creatinine levels if you show signs of kidney disease. These symptoms include:
- fatigue and trouble sleeping
- a loss of appetite
- swelling in the face, wrists, ankles, or abdomen
- lower back pain near the kidneys
- changes in urine output and frequency
- high blood pressure
Kidney problems can be related to different diseases or
Aminoglycoside medications, such as gentamycin,
can also cause kidney damage in some people. If you’re taking this type of
medication, your doctor may order regular creatinine blood tests to make sure
your kidneys remain healthy.
Do I Prepare for a Creatinine Blood Test?
A creatinine blood test doesn’t require very much preparation. However,
it’s important to tell your doctor about any prescription or over-the-counter
medications you’re currently taking. Some drugs may increase your creatinine
levels without causing kidney damage and interfere with your test results. Let
your doctor know if you take:
- nonsteroidal anti-inflammatory drugs (NSAIDs),
such as aspirin or ibuprofen
- chemotherapy drugs
Your doctor may ask you to stop taking your medication or to
adjust your dosage before the test. They’ll also take this into consideration
when interpreting your test results.
Can I Expect During a Creatinine Blood Test?
The creatinine blood test is a simple test that requires the
removal of a small sample of blood.
A technician called a phlebotomist will ask you to pull up your
sleeves so that your arm is exposed. They’ll sterilize the injection site with
an antiseptic and then tie a band around your arm. This makes the veins swell
with blood, allowing them to find a vein more easily. Once they find a vein, they’ll
insert a needle into it to collect the blood. In most cases, a vein on the
inside of the elbow is used. You might feel a slight prick when the needle is
inserted, but the test itself isn’t painful. After the phlebotomist removes the
needle, they’ll put a bandage over the puncture wound.
A creatinine blood test is a low-risk procedure. However, there
are some minor risks, including:
- fainting at the sight of blood
- dizziness or vertigo
- soreness or redness at the puncture site
Once enough blood is drawn, the sample is sent to a laboratory
for analysis. Your doctor will give you the results within a few days of
Do My Creatinine Blood Test Results Mean?
Creatinine is measured in milligrams per deciliter of blood
(mg/dL). People who are more muscular tend to have higher creatinine levels.
Results may also vary depending on age and gender.
In general, however, normal creatinine levels range from 0.7 to
1.3 mg/dL in men and 0.6 to 1.1 mg/dL in women.
High serum creatinine levels in the blood indicate that the
kidneys aren’t functioning properly.
Your serum creatinine levels may be slightly elevated or higher
than normal due to:
- a blocked urinary tract
- a high-protein diet
- kidney problems, such as kidney damage or
- reduced blood flow to the kidneys due to shock,
congestive heart failure, or complications of diabetes
It’s uncommon to have low levels of creatinine, but this can
occur as a result of certain conditions that cause decreased muscle mass.
They’re usually not any cause for concern.
It’s important to note that normal and abnormal ranges can vary
among labs because some use unique measurements or test different samples. You
should always meet with your doctor to discuss your test results in more
detail. They’ll be able to tell you if more testing is necessary and if any
treatment will be required.