Blood tests are a very useful testing tool. Blood is a sticky red fluid with a salty taste, and is slightly alkaline in reaction. It is made up of liquid portion which is called as plasma and remaining portion is solid which is called as the blood cells.

The purpose of blood clotting is to plug down and set free an enzyme which reacts with other clotting substances in the blood. The result is a jelly like mass composed of a network of threads around the blood cells. The clot soon reduces its size and serum comes away from it. This serum is used in chemical tests and in the test to find out how the immune system fights diseases.

Blood samples are taken by doctors, seen through a microscope and find out the infectious diseases.

How Blood Test Carried Out?

Blood test is carried out on a small sample of blood, which is taken from a vein in your arm using a fine needle and a small syringe. Although some people dislike needles, the blood test causes minimal discomfort. The sample is then sent to a specialist laboratory, and the results are available within a few days.

Blood will be drawn either at this first visit for routine blood analysis or at a later visit for the Alpha-fetoprotein test. A nurse will take your blood by inserting a needle into a vein on the inside bends of your elbow.

To take finger prick blood test, the nurse initially take a ball of cotton dipped with spirit, cleans with the cotton and will prick the tip of the finger and then squeeze the finger to draw a drop of blood. This blood is placed on a glass slide for laboratory analysis.

If the blood is taken from an artery, it is usually taken from the wrist where there is an artery that is close to the skin. Sometimes artery will not be visible to take blood. It takes little trouble; lastly the artery can be visible. After taking blood from the artery it is necessary to keep a cotton ball on the place where the
injection was made for few minutes to stop bleeding.

How The Blood Is Examined By Doctors?

Blood is made up of liquid plasma and solids the blood cells. Plasma is a pale yellow fluid consisting of water ninety percent, salts including sodium chloride 0.9 percent, proteins including albumen which make the blood sticky, nutrients such as glucose, fats, amino acids and vitamins, waste products such as urea and carbondioxide, antibodies and antitoxins for resistance to disease germs, hormones produced by the endocrine glands, substances for blood clotting and for preventing clotting of blood. Plasma is very important for the life of the tissue cells, conveying to them water and nourishment, and carrying away their waste products. There are three main types of blood cells: red blood cells, white blood cells and blood platelets. To get the information of these cells, blood samples are taken.

These tests are listed below:

Red blood cells are the most numerous. They are formed in the bone marrow and wear out in about three months, so need replacing. They are very tiny discs with no nucleus, and are filled with hemoglobin which is made from iron and protein. Hemoglobin gives the blood its red color. The normal amount of hemoglobin is 14.5 to 15 grams of blood. Lack of iron to make hemoglobin is a common cause of anemia.

Doctors add some stains to the blood smear to test the blood for parasites in the case of sleeping sickness or for malaria. In case if blood poisoned the doctor take test whether any bad bacteria is present.

White blood cells help to fight infection and therefore, are an important part of the immune system. The risk of developing an infection is due to low white blood cell count increases. There are several kinds of white blood cells; Neutrophils are important white cells that help fight infections caused by bacteria and yeasts. Others, called lymphocytes, carry the immunologic memory to protect against viral and other infections, especially those for which people receive vaccinations.

Blood Platelets are produced in the bone marrow and help in the clotting of blood during injury. Platelets are very smaller than red and white blood cells. The risk of bleeding and bruising is due to low platelet count increases