What are blood tests?
A blood test is a medical test that is used to find out numerous data about the organism, which helps specialists to verify the patient’s state of health. From a small amount of blood studied in the laboratory, multiple diseases, infections, coagulation problems, blood cancers and diseases of the immune system can be diagnosed.
What do blood tests consist of?
Blood has to be drawn from the inside of the elbow using a fine needle and a syringe. The blood sample is placed in a centrifuge in a laboratory and spun until the blood separates.
Why are blood tests performed?
Laboratory tests can be classified according to the data to be assessed:
- Cardiovascular tests (e.g., cholesterol and lipid tests).
- Liver function tests
- Renal function tests
- Thyroid function tests
- Reproductive function tests
- Vitamin tests
- Carbohydrate tolerance test
- White blood cell test
- Red blood cell test
Having a blood test done annually with a physician can help detect any disease or condition early, to aid in more successful treatment. Some laboratories also offer the possibility of home collection.
Clinical blood tests are often performed before surgery to assess the patient’s state of health.
Preparation for blood tests
Prior to blood tests, it is necessary to fast for 8 to 12 hours. Most blood tests are carried out in the morning, so it is easier to follow the fasting during the night.
The reason for fasting is that when we eat or drink, food is absorbed into the bloodstream, which can affect the test results, depending on the type of test. This does not mean that you cannot drink water, unless instructed to do so by your physician. Also, you should not chew gum, smoke or exercise before the test.
You can eat and drink immediately after the test. In fact, it is recommended that you bring a snack for after the test because you may feel dizzy.
What does it feel like to have a blood test?
Blood is usually drawn from the inside of the arm. A tourniquet is used on the upper arm to slow the blood flow and allow the vein to swell. The skin is cleansed and the needle is injected into the vein.
A syringe draws the blood and once the pressure is taken, it is applied to the area. A small piece of gauze may be used to cover the wound. The blood draw is not painful, but some people find it uncomfortable.
What do abnormal results mean?
Once the blood sample has been tested in a laboratory, the results can sometimes be viewed online or sent to the patient or physician. Most results will require interpretation by a professional and should be shared with the specialist. If any abnormalities are indicated, they may need to do additional testing, including further blood work, but also scans or biopsies.