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May 2024

All you need to know about blood tests

Posted By Suborna Fermi Posted on May 31, 2024

Blood tests are one of the most preferred diagnostic tests healthcare providers use to detect disease and monitor overall health. Generally, a blood test is needed as part of your routine checkup or recommended when you are having certain symptoms.

What are blood tests?

Blood tests are the most common medical tests. You may require a blood test as a part of your routine health checkup, or when experiencing certain symptoms.

There are various types of blood tests. Certain tests help examine the levels of different blood components, while certain tests examine different substances, such as hormones and proteins in the blood.

When do you need a blood test?

Your blood contains various information about what is going on in your body. Therefore, your doctor may recommend a blood test in the following cases:

  • During your routine health examination: During a physical health checkup, your doctor may order certain blood tests to check on your health. Doctors generally recommend a complete blood count, a basic metabolic panel, or a comprehensive metabolic panel.
  • If you are at risk of disease: Your doctor may recommend taking a specific blood test if you are at risk of developing a certain disease. This is generally required if you have a known genetic mutation that can cause a disease.
  • To monitor your existing medical condition: If you are getting treatment for a specific condition, your doctor may order certain tests to check how you are responding to the treatment.
  • If you are having symptoms: If you are experiencing certain symptoms then your doctor may recommend taking certain specific tests to confirm a suspected diagnosis.
  • Before surgery: Doctors generally recommend blood tests before surgery to check for issues that may increase risks during surgery.
  • If you are pregnant: During pregnancy, a healthcare provider may run a range of blood tests to check if you are at risk of pregnancy complications.
  • If you wish to improve your health: Having certain blood tests can help you understand your health better, and allow you to make changes to improve your health. For example, a lipid panel test helps examine the levels of HDL and LDL in your blood, which allows you to make changes in your diet and lifestyle to improve your heart health.

Apart from the routine blood tests, one should get a lipid profile test at the age of 20 years. People with a lower risk of a heart attack may get a lipid profile test once every 5 years. People with a higher risk of having a heart attack may require a lipid test more frequently.

People over 40 years old need to check their blood sugar levels once a year. On the other hand, people who are overweight or obese need to check their blood sugar levels more frequently. In addition to that, people over age 45 need to be screened for colorectal cancer regularly.

5 most common blood tests that you should know about:

1. Complete blood count

A complete blood count is a widespread yet crucial test that examines the levels of different components in your blood. Hemoglobin, white blood cells, red blood cells, and platelets are a few major blood components this test measures.

Abnormal range of these components may indicate:

  • Infection
  • Clotting disorder
  • Nutritional deficiency
  • Anemia
  • Immune system disorder
  • Blood cancer

Your doctor may recommend additional tests depending on your test results.

2. Basic metabolic panel

A basic metabolic panel examines the levels of eight different components in the blood, such as glucose, sodium, potassium, calcium, chloride, bicarbonate, blood urea nitrogen, and creatinine. You might be required to fast for 10-12 hours before the test.

Abnormal range of the mentioned components may indicate:

  • Diabetes
  • Kidney disease
  • Electrolytes imbalance

Your doctor may order additional tests to confirm a diagnosis.

3. Comprehensive metabolic panel

A comprehensive metabolic panel examines the levels of all the measurements of a basic metabolic panel and certain additional components related to liver function. The levels of albumin, alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, total protein and bilirubin are measured in this test.

High levels of alkaline phosphatase may indicate:

  • Hepatitis
  • Cirrhosis
  • Bile duct blockage
  • Gallstones
  • Gallbladder inflammation
  • Mononucleosis
  • Paget’s disease

High levels of alanine aminotransferase may indicate:

  • Hepatitis
  • Cirrhosis
  • Liver damage
  • Liver cancer

High levels of aspartate aminotransferase may indicate:

  • Hepatitis
  • Cirrhosis
  • Heart disease
  • Mononucleosis
  • (Mono) pancreatitis

High levels of bilirubin may indicate:

  • Hepatitis
  • Bile duct blockage
  • Hemolysis
  • Gilbert's syndrome
  • Adverse medicinal reaction

Low levels of alkaline phosphatase may indicate:

  • Malnutrition
  • Bone metabolism disorder
  • Zinc deficiency

Usually, lower levels of alanine aminotransferase, aspartate aminotransferase, and bilirubin do not cause medical concern.

4. Lipid profile test

A lipid panel evaluates cholesterol levels, such as high-density lipoprotein or “good” cholesterol and low-density lipoprotein or “bad” cholesterol. High-density lipoprotein is considered “good” cholesterol because it eliminates toxic substances from your blood and helps the liver break them into wastes. On the other hand, low-density lipoprotein is considered “bad” cholesterol as it causes plaque buildup in the arteries that increase the risk of heart disease.

You are required to fast for about 8-10 hours before the test. The normal range may vary depending on the age. High levels of low-density lipoprotein and lower levels of high-density lipoprotein may indicate that you are at risk of developing heart disease.

5. Thyroid profile test

A thyroid panel or profile test measures the levels of triiodothyronine (T3), thyroxine (T4), and thyroid stimulating hormone (TSH) in your blood to analyze how well your thyroid gland is working. The thyroid hormones help regulate body temperature and metabolism.

Abnormal range of thyroid hormones may indicate:

  • Thyroid growth disorders
  • Low protein levels
  • Abnormal levels of estrogen and testosterone

6. Cardiac risk markers

Enzymes are a type of protein that is essential to conducting certain chemical processes, including breaking down foods and clotting blood. These enzymes are essential for various body functions. A cardiac risk markers test helps evaluate the levels of certain enzymes in the body to check your heart health.

7. Sexually transmitted infection test

Sexually transmitted infections can be diagnosed with the help of a simple blood test. Your doctor may recommend taking a urine test along with an STI test. Abnormal test results may indicate:

  • HIV
  • Herpes
  • Syphilis
  • Hepatitis C

However, in certain cases, getting a test for sexually transmitted infection may not give accurate test results. For example, in the case of HIV infection, a blood test can detect the virus one month after the contraction.

8. DHEA-sulfate serum test

A DHEA-sulfate serum test evaluates the level of dehydroepiandrosterone (DHEA) hormone in your blood. In males, this hormone helps develop traits like body hair growth. Therefore, low levels of this hormone in males are abnormal. High levels of this hormone in females may contribute to develop male traits, and low levels are considered normal.

Abnormal levels of this hormone may indicate:

  • Adrenal dysfunction
  • Hypopituitarism
  • Addison’s disease
  • Premature puberty in females
  • Use of steroid medication

Before going for any type of blood test, ask your healthcare providers whether you need to fast.

Blood tests are a great medical process to evaluate your overall health. They are ideal for detecting a disease and to monitor your existing condition. Some people require routine blood tests once a year, while others need to get tested more frequently. Consult your doctor to understand whether you need any tests to make sure you are at your optimal health.