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Definition
Three different types of blood tests are performed:
Hematologic (for anemia, etc.): white blood cell count, red blood cell count, hemoglobin, hematocrit, platelet count, blood profile
Biochemical (for liver, kidneys, pancreatic function, lipid, glucose metabolism, etc.): GOT, GPT, γ-GTP, total protein, albumin, creatinine, total cholesterol, HDL cholesterol, LDL cholesterol, neutral lipid, uric acid, glucose, ALP, LDH, total bilirubin, amylase, Ca, BUN
Serologic (for antibodies, internal secretions, infectious diseases, etc.): RF, TSH, HBs antigen, HCV antibody, ABO blood type, Rh(D) blood type, FT4, syphilis qualitative, TPHA test, CRP
Blood for all tests, including tumor marker tests, will be drawn at one time to avoid the need for multiple needle insertions.
How the test is performed
Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic. An elastic band is placed around the upper arm to apply pressure and cause the vein to swell with blood.
A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the band is removed to restore circulation. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.
In infants or young children, the area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. A bandage may be applied to the puncture site if there is any bleeding.
How to prepare for the test
No special preparation is usually needed.
How the test will feel
When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.
Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample may be more difficult from some people than from others.
What the risks are
- Excessive bleeding (rare)
- Fainting or feeling lightheaded
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
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