lood tests help doctors check for certain diseases and conditions. They also help check the function of your organs and show how well treatments are working. About 50 percent of the information in the average medical chart comes from laboratory data. Diagnostic test results, including blood tests, inform approximately 70 percent of medical decisions.
“Many patients consider having a blood test to be a simple procedure, but don’t understand what takes place behind the scenes between when the blood is drawn and when the doctor makes a diagnosis,” said Dr. Sunidhi Shreya, Postgraduate Resident, Dept. of Microbiology, MAMC, New Delhi. “Laboratory blood tests are a vital part of the diagnostic process, helping physicians make the correct diagnosis and determine the appropriate course of treatment.”
Regular blood testing is one of the most important ways to keep track of your overall physical well-being. Some of the most common blood tests are:
A complete blood count (CBC)
Blood chemistry tests
Blood enzyme tests
Blood tests to assess heart disease risk
A COMPLETE BLOOD COUNT (CBC) : The complete blood count (CBC) is a group of tests that evaluate the cells that circulate in blood, including red blood cells (RBCs), white blood cells (WBCs), and platelets (PLTs). The CBC is one of the most common blood tests. It’s often done as part of a routine check-up. This test measures many different parts of your blood, as discussed in the following paragraphs.
Red Blood Cells : Red blood cells, also called erythrocytes, are produced in the bone marrow and released into the bloodstream when they mature. Red blood cells carry oxygen from your lungs to the rest of your body. Abnormal red blood cell levels may be a sign of anemia, dehydration (too little fluid in the body), bleeding, or another disorder.
White Blood Cells : White blood cells, also called leukocytes, are cells that exist in the blood, the lymphatic system, and tissues and are an important part of the body’s natural defence (immune) system. Abnormal white blood cell levels may be a sign of infection, blood cancer, or an immune system disorder.
Platelets : Platelets, also called thrombocytes, are actually tiny cell fragments that circulate in blood and are essential for normal blood clotting. They stick together to seal cuts or breaks on blood vessel walls and stop bleeding. The process of spreading across the surface of a damaged blood vessel to stop bleeding is called adhesion.
Haemoglobin : Haemoglobin is an iron-rich protein in red blood cells that carries oxygen. The oxygen-carrying pigment and predominant protein in the red blood cells. Haemoglobin forms an unstable, reversible bond with oxygen. If you have diabetes, excess glucose in your blood can attach to haemoglobin and raise the level of haemoglobin A1c.
Haematocrit : A haematocrit test is a type of blood test. Your blood is made up of red blood cells, white blood cells, and platelets. These cells and platelets are suspended in a liquid called plasma. A haematocrit test measures how much of your blood is made up of red blood cells. Abnormal haematocrit levels also may be a sign of a blood or bone marrow disorder.
Mean Corpuscular Volume : MCV stands for mean corpuscular volume. There are three main types of corpuscles (blood cells) in your blood–red blood cells, white blood cells, and platelets. An MCV blood test measures the average size of your red blood cells, also known as erythrocytes. Abnormal MCV levels may be a sign of anemia or thalassemia.
BLOOD CHEMISTRY TESTS : A test done on a sample of blood to measure the amount of certain substances in the body. These substances include electrolytes (such as sodium, potassium, and chloride), fats, proteins, glucose (sugar), and enzymes. Blood chemistry tests give important information about how well a person’s kidneys, liver, and other organs are working.
BLOOD ENZYME TESTS : Enzyme markers are blood tests that analyse specific enzyme activity in the body. There are many blood enzyme tests. This section focuses on blood enzyme tests used to check for heart attack. These include troponin and creatine (KRE-ah-teen) kinase (CK) tests.
Troponin : A troponin test measures the levels of troponin T or troponin I proteins in the blood. These proteins are released when the heart muscle has been damaged, such as occurs with a heart attack. When muscle or heart cells are injured, troponin leaks out, and its levels in your blood rise.
Creatine Kinase :A creatine kinase (CK) test may be used to detect inflammation of muscles (myositis) or muscle damage due to muscle disorders (myopathies) such as muscular dystrophy or to help diagnose rhabdomyolysis if a person has signs and symptoms.
BLOOD TESTS TO ASSESS HEART DISEASE : A lipoprotein panel is a blood test that can help show whether you’re at risk for coronary heart disease (CHD). This test looks at substances in your blood that carry cholesterol. A lipoprotein panel gives information about;
High-density lipoprotein (HDL), or “good” cholesterol
Low-density lipoprotein (LDL), or “bad” cholesterol.