A creatinine blood test is a blood examination that is done to check the level of creatinine in the kidneys. Creatinine is the waste product of creatine, which supplies energy to the skeletal muscles. The blood test is done to see if the kidneys of a person are functioning normally or to check the status of a person’s kidney that has developed a disease. A creatinine blood test also is performed to ensure that a person who takes medicines that can damage the kidneys is spared from such damage.
Doctors sometimes order another blood test called the blood urea nitrogen (BUN) test to be done together with the creatinine blood test to check if the BUN-to creatinine ratio is higher or lower than the normal values, which usually range from 10-to-1 up to 20-to-1. A ratio higher than normal might be a result of a decrease in blood flow to the kidneys because of congestive heart failure or dehydration. A ratio that is lower than normal, on the other hand, might be caused by malnutrition or disease of the liver brought about by a decrease in the production of urea inside the body.
The conducting of a creatinine blood test requires a blood sample that is extracted from a vein in the arm of a person by a health professional, usually a medical technologist. The medical technologist will wrap an elastic band tightly around the upper arm of the person to stop blood flow and cause the veins below the band to bulge. This will facilitate the insertion of a needle that will draw blood to the barrel of the syringe when the plunger is pulled. After removing the needle from the patient's arm, the medical technologist will transfer the blood sample to a vial and take it to the laboratory for analysis.
A person who will undergo creatinine blood test is required to fast for at least eight hours before the test. This means that nothing can be orally taken from the time the fasting commences until the blood test is completed. A person should not fast for more than 12 hours; this will result in the cancellation of the test because over-fasting will produce unreliable test results. Over-fasting also might result in hypoglycemia — a condition in which the blood glucose becomes too low to provide the energy needed to do an activity. People taking the test, therefore, should avoid over-fasting to prevent delay in the test.
Doctors urge each person to have an annual check-up to maintain healthy kidneys and other vital organs. Some diseases can cause total kidney failure, which could lead to death. This can be avoided through proper health care. A friendly reminder from doctors: Prevention is better than cure — always.