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#1 2024-03-07 19:00:15

Jai Ganesh
Registered: 2005-06-28
Posts: 46,412

Blood Test

Blood Test


Blood tests are common medical tests. You may have a blood test as part of a routine physical examination or because you have certain symptoms.

There are many different blood tests. Some tests focus on your blood cells and platelets. Some evaluate substances in your blood such as electrolytes, proteins and hormones. Others measure certain minerals in your blood.

Regardless of why you’re having a blood test, it’s important to remember that blood tests help healthcare providers diagnose health issues. But blood test results aren’t diagnoses. An abnormal blood test result may not mean you have a serious medical condition.


A blood test is a laboratory analysis performed on a blood sample that is usually extracted from a vein in the arm using a hypodermic needle, or via fingerprick. Multiple tests for specific blood components, such as a glucose test or a cholesterol test, are often grouped together into one test panel called a blood panel or blood work. Blood tests are often used in health care to determine physiological and biochemical states, such as disease, mineral content, pharmaceutical drug effectiveness, and organ function. Typical clinical blood panels include a basic metabolic panel or a complete blood count. Blood tests are also used in drug tests to detect drug abuse.


A venipuncture is useful as it is a minimally invasive way to obtain cells and extracellular fluid (plasma) from the body for analysis. Blood flows throughout the body, acting as a medium that provides oxygen and nutrients to tissues and carries waste products back to the excretory systems for disposal. Consequently, the state of the bloodstream affects or is affected by, many medical conditions. For these reasons, blood tests are the most commonly performed medical tests.

If only a few drops of blood are needed, a fingerstick is performed instead of a venipuncture.

In dwelling arterial, central venous and peripheral venous lines can also be used to draw blood.

Phlebotomists, laboratory practitioners and nurses are those in charge of extracting blood from a patient. However, in special circumstances, and/or emergency situations, paramedics and physicians extract the blood. Also, respiratory therapists are trained to extract arterial blood to examine arterial blood gases.

Types of tests:

Biochemical analysis

A basic metabolic panel measures sodium, potassium, chloride, bicarbonate, blood urea nitrogen (BUN), magnesium, creatinine, glucose, and sometimes calcium. Tests that focus on cholesterol levels can determine LDL and HDL cholesterol levels, as well as triglyceride levels.

Some tests, such as those that measure glucose or a lipid profile, require fasting (or no food consumption) eight to twelve hours prior to the drawing of the blood sample.

For the majority of tests, blood is usually obtained from the patient's vein. Other specialized tests, such as the arterial blood gas test, require blood extracted from an artery. Blood gas analysis of arterial blood is primarily used to monitor carbon dioxide and oxygen levels related to pulmonary function, but is also used to measure blood pH and bicarbonate levels for certain metabolic conditions.

While the regular glucose test is taken at a certain point in time, the glucose tolerance test involves repeated testing to determine the rate at which glucose is processed by the body.

Blood tests are also used to identify autoimmune diseases and Immunoglobulin E-mediated food allergies (see also Radioallergosorbent test).


Blood testing is the lab analysis of the blood found in your body. Blood testing is usually prescribed if you need to keep track of the progress of a specific treatment, manage health conditions such as high cholesterol, diabetes, illness, or routine checkup. Blood testing is widespread and is usually done by the doctor themselves or at your local diagnostic centre. Knowing the different blood test names and meanings can help you better understand their uses and benefits.

Why do blood tests matter?

A blood test is carried out for a wide variety of reasons:

* To find out how well vital organs such as your heart, liver, kidneys, or thyroid are working
* To help diagnose lifestyle diseases like diabetes, cancer, coronary heart disease, or AIDS/HIV
* To understand whether the prescribed medicine is working
* To diagnose clotting or bleeding disorders
* To identify health issues at an early stage
* To monitor chronic diseases and health conditions

The blood test reports help your doctor get a basic idea of your overall health and prescribe specialised tests to get an accurate diagnosis.

Types of blood tests

The list of blood tests can be very long. Here are some of the common ones that you need to know about.

Complete blood count (CBC)

This routine blood test checks ten different components of the blood, including red blood cells, white blood cells, platelets, haemoglobin, and hematocrit. Any abnormalities in the normal levels of these components can indicate

* nutritional deficiencies,
* anaemia,
* blood cancer,
* infections,
* problems with the immune system, or
* clotting problems.

You may have to undergo a few follow-up tests to get a more precise diagnosis of your issues.

Basic metabolic panel (BMP)

This test checks for the following eight components in the blood:

* Glucose
* Calcium
* Sodium
* Potassium
* Bicarbonate
* Chloride
* Blood urea nitrogen
* Creatinine

You may be asked to avoid eating anything for at least 8 hours before the sample is taken, depending on the parameters you need to measure and the doctor's instructions. Abnormal results in this test may be a result of

* diabetes,
* kidney disease, or
* hormone imbalance.

Comprehensive metabolic panel (CMP)

In this test, all the parameters checked in the BMP are measured along with a few others, like

* total protein,
* albumin,
* alkaline phosphatase,
* alanine aminotransferase,
* aspartate amino transferase, and
* bilirubin.

Abnormalities in these tests can indicate many health issues depending on whether the levels of components are higher or lower than the normal range.

Lipid panel

Lipid test is used to check the levels of two types of cholesterol in the body:

* High-density lipoprotein (HDL): It is also known as good cholesterol because it helps the liver remove harmful toxins from the body by breaking them down into waste.
* Low-density lipoprotein (LDL): It is also called bad cholesterol as it can cause plaque which clogs the blood vessels and increase the risks of heart disease.

Thyroid panel

The thyroid panel blood test, or the thyroid function test, is used to identify how well your thyroid functions when reacting to or producing hormones like

* Thyroxine,
* Triiodothyronine, and
* Thyroid-stimulating hormone.

Abnormal levels of hormones in the body can indicate conditions such as

* thyroid growth disorders,
* low protein levels, and
* abnormal levels of estrogen or testosterone.

Cardiac biomarkers

An enzyme is a protein which helps the body carry out chemical processes like breaking down food or clotting blood. Some of the standard blood tests for enzymes include

* Creatine kinase
* Troponin
* Creatine kinase-MB

Abnormal levels of enzymes indicate a wide range of issues that may need further testing.

Sexually transmitted infection (STI) tests

Most STIs are diagnosed with the help of a blood test or a blood and urine test combined. Some of the common STIs that can be identified using a blood test are

* Gonorrhea
* herpes
* syphilis
* chlamydia

In some cases, blood tests have their limitations. For example, a test for HIV will be able to detect the virus only after a month of the infection.

Coagulation panel

A coagulation test is used to measure how long it takes for your blood to clot as well as how effectively it clots. Clotting is important for wound healing; however, if a clot forms in an artery or vein, it can block the blood flow to vital organs and cause health issues.

The results of these tests help doctors diagnose

* haemophilia (the condition in which you bleed excessively),
* liver conditions,
* Vitamin K deficiency,
* leukaemia, and
* thrombosis.

Electrolyte panel

This blood test helps measure the levels of different minerals in your body. Any imbalance in these levels may indicate problems with vital organs like the kidneys, lungs, or heart. Along with all the parameters in the BMP and CMP, this test also checks the magnesium and anion gap levels.

Allergy testing

An allergy blood test can identify increased levels of immunoglobulin E (IgE). It can help detect allergies for such as pollen, pets, various food items, and other substances.

Autoimmune diseases

An autoimmune disease is a result of your immune system accidentally attacking your body instead of protecting it from parasites, cancer, and viruses. Autoimmune tests include the following:

* C-reactive protein tests
* peripheral blood smears
* erythrocyte sedimentation rate
* CE complement blood tests
* antinuclear antibody tests

After preliminary testing, blood tests can also be used to identify specialised issues such as cancer, heart disease, and endocrine system disorders.


A blood test can give you an overall idea of your health. It can be used to identify diseases or illnesses at an early stage. It also helps your healthcare provider understand how well your body is responding to treatment. Most people get routine blood tests at least once a year to stay on top of their health. You can talk to your doctor about some routine tests to ensure you are in optimal health or opt for medical testing packages available at Metropolis Labs.

Additional Information

Blood tests are very common. They help doctors check for certain diseases and conditions. They also help check the function of your organs and show how well treatments are working.

Complete blood count (CBC)

The complete blood count (CBC) is one of the most common blood tests. It is often done as part of a routine checkup. This test measures many different parts of your blood, including red blood cells, white blood cells, and platelets.

* Red blood cell levels that are higher or lower than normal could be a sign of dehydration, anemia, or bleeding. Red blood cells carry oxygen from your lungs to the rest of your body.
* White blood cell levels that are higher or lower than normal could be a sign of infection, blood cancer, or an immune system disorder. White blood cells are part of your immune system, which fights infections and diseases.
* Platelet levels that are higher or lower than normal may be a sign of a clotting disorder or a bleeding disorder. Platelets are blood cell fragments that help your blood clot. They stick together to seal cuts or breaks on blood vessel walls and stop bleeding.
* Hemoglobin levels that are lower than normal may be a sign of anemia, sickle cell disease, or thalassemia. Hemoglobin is an iron-rich protein in red blood cells that carries oxygen.
* Hematocrit levels that are too high might mean you’re dehydrated. Low hematocrit levels may be a sign of anemia. Hematocrit is a measure of how much space red blood cells take up in your blood.
* Mean corpuscular volume (MCV) levels that are lower than normal may be a sign of anemia or thalassemia. MCV is a measure of the average size of your red blood cells.

Blood chemistry tests/basic metabolic panel

The basic metabolic panel (BMP) is a group of tests that measures different naturally occurring chemicals in the blood. These tests usually are done on the fluid (plasma) part of blood. The tests can give providers information about your organs, such as the heart, kidneys, and liver.

The BMP includes blood glucose, calcium, and electrolyte tests, as well as blood tests that measure kidney function. Some of these tests require you to fast (not eat any food) before the test, and others don't. Your provider will tell you how to prepare for the test(s) you're having.

Blood enzyme tests

Blood enzyme tests may be used to check for heart attack. Enzymes are chemicals that help control chemical reactions in your body. There are many types of blood enzyme tests. The ones for heart attack include troponin and creatine kinase (CK) tests.

Blood levels of troponin go up when a person has muscle damage, including damage to the heart muscle. In addition, an enzyme called CK-MB is released into the blood when the heart muscle is damaged. High levels of CK-MB in the blood can mean that you've had a heart attack.

Lipoprotein panel

A lipoprotein panel, also called a lipid panel or lipid profile, measures the levels of LDL and HDL cholesterol and triglycerides in your blood. Cholesterol and triglyceride levels that are higher or lower than normal may be signs of higher risk of coronary heart disease.

A lipoprotein panel gives information about your:

* Total cholesterol
* LDL ("bad") cholesterol, which is the main source of cholesterol buildup and blockages in the arteries
* HDL ("good") cholesterol, which helps decrease cholesterol blockages in the arteries
* Triglycerides, which are a type of fat in your blood

Most people will need to fast for 9 to 12 hours before a lipoprotein panel.

Blood clotting tests

Blood clotting tests are sometimes called a coagulation panel. These tests check proteins in your blood that affect the blood clotting process. Levels that are higher or lower than normal might suggest that you're at risk of bleeding or developing clots in your blood vessels.

Blood clotting tests also are used to monitor people who are taking medicines to lower the risk of blood clots. Warfarin and heparin are two examples of such medicines.

Bone marrow tests

Bone marrow tests check whether your bone marrow is healthy and making normal amounts of blood cells. The two bone marrow tests are aspiration and biopsy.

* Aspiration collects a small amount of bone marrow fluid through a larger needle.
* Biopsy tests are often done at the same time as the aspiration test. A biopsy test collects a small amount of bone marrow tissue through a larger needle.

These tests can help find the cause of low or high blood cell counts. They also play an important role in checking how well treatments for certain types of cancers, such as leukemia or lymphoma, are working.

Before this procedure, be sure to tell your provider about current medicines you are taking, known allergies to medicines, if you are pregnant, or if you have a bleeding disorder.

Bone marrow tests can be done in a hospital or doctor’s office or clinic. You may be awake for your test and may be given medicine to relax you during the test. You may also be under anesthesia for this test, if recommended by your care team. You will lie on your side or stomach or back, depending on where your provider obtains the samples from. Your provider will clean and numb the top ridge of the hipbone or rib bone, where the needle will be inserted. You may feel a brief, sharp pain when the needle is inserted and when the bone marrow is aspirated. The bone marrow samples will be studied in a laboratory.

After your test, you will have a small bandage on the site where the needle was inserted. Most people go home the same day. You will need a ride home if you received medicines to relax you during the test. You may have mild discomfort but likely won’t have any pain after the test. Your doctor may have you take an over-the-counter pain medicine. Call your provider if you are in serious pain or if you develop symptoms including:

* Fever
* Redness
* Swelling
* Discharge at the needle injection site.


It appears to me that if one wants to make progress in mathematics, one should study the masters and not the pupils. - Niels Henrik Abel.

Nothing is better than reading and gaining more and more knowledge - Stephen William Hawking.


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