Blood tests can provide information about many substances found in blood, such as blood cells, hormones, minerals, and proteins.
Drawing blood poses little risk to a person, and test results can be obtained quickly.
Numerous tests can be conducted using a single blood sample.
Blood is the body fluid most commonly analyzed for disease screening and diagnosis. Blood tests can provide information about many substances found in blood, such as hormones, minerals, and proteins. Some of the more common blood tests examine red or white blood cells, proteins, hormones, and enzymes.
Typically, a technician, nurse, or physician draws blood from a vein using a syringe, a process called venipuncture. Venipuncture blood samples are commonly used to:
Screen for a disease;
Establish a diagnosis;
Establish a prognosis;
Rule out a clinical problem;
Monitor therapy; and
Determine an effective drug dosage.
In cardiology, the most frequently ordered blood tests include:
Cardiac enzymes, including creatine phosphokinase, myoglobin, and troponin;
Brain natriuretic peptide;
International normalized ratio;
Lipid levels; and
A physician may request that the patient avoid certain medications or refrain from eating or drinking prior to the test.
WHAT TO EXPECT
When blood is drawn, a tourniquet is wrapped around the arm. The patient makes a fist and a sterile, disposable needle is inserted into the vein. A syringe or attached vial is used to collect that blood. After the procedure is complete, a piece of gauze is placed over the insertion point and pressure is applied to stop the bleeding.
Patients can resume normal activities following the blood test.
Some patients may experience temporary bruising at the site of the puncture.