Why do I need to have my blood drawn when I go to the hospital for a physical examination?

In daily life, when we feel unwell or want to prevent diseases, we often choose to go to the hospital for a physical examination. During the physical examination, blood tests are often an indispensable part. Many people are nervous or confused about blood tests and don’t understand why they need to draw blood for physical examinations. This article will explain in detail from multiple perspectives why blood tests are needed when going to the hospital for a physical examination and the importance of blood tests.

1. Purpose of blood test

Blood tests are one of the most commonly used examination methods in hospitals. Their purpose is to assess the health of the human body by testing various components and indicators in the blood, helping doctors diagnose diseases, determine the severity of the disease, and monitor the effectiveness of treatment. Blood plays a vital role in the human body. It is responsible for transporting nutrients, oxygen, hormones, and metabolic waste, and is also involved in immune responses and coagulation processes. Therefore, changes in blood components can reflect the functions and health of multiple systems in the human body.

2. Blood test items

There are many items in the blood test, covering blood routine, biochemical indicators, immunological indicators, blood coagulation function, etc. Let's take a look at these test items and their significance one by one.

1. Blood routine test

Routine blood test is one of the most basic blood tests, mainly detecting the number and morphology of red blood cells, white blood cells and platelets in the blood. Red blood cells are responsible for transporting oxygen, and a decrease in their number may indicate anemia; white blood cells are an important part of the immune system, and changes in their number and classification can reflect infection, inflammation or immune response; platelets are involved in the coagulation process, and too much or too little of them may affect the coagulation function.

2. Biochemical indicators

Biochemical indicators detect the content of various chemical substances in the blood, such as blood sugar, blood lipids, liver function indicators, etc. Blood sugar levels reflect the body's ability to metabolize sugars. Too high or too low may indicate diabetes or other metabolic diseases; blood lipid levels are closely related to the risk of cardiovascular disease; liver function indicators such as transaminase and bilirubin can reflect the health status and degree of damage of the liver.

3. Immunological indicators

Immunological indicators detect the number and functional status of immune cells in the blood, such as white blood cell count, lymphocyte subset analysis, etc. These indicators can reflect the health of the human immune system and are of great significance for preventing infectious diseases and autoimmune diseases.

4. Blood coagulation function

Blood coagulation function tests the ability of blood to form blood clots in blood vessels. This test helps doctors understand whether the patient's coagulation system is normal, which is of great significance for preventing thrombotic diseases such as myocardial infarction and stroke.

3. The significance of blood test

1. Assess your health status

Blood tests can comprehensively evaluate the health of the human body, including the blood system, immune system, metabolic system, etc. By testing various components and indicators in the blood, doctors can understand the overall health of the patient and provide a basis for formulating personalized health management plans.

2. Diagnose diseases

Many diseases do not have obvious symptoms in the early stages of the disease, but the blood composition has already changed. By taking blood tests, doctors can detect these changes in time and diagnose potential diseases. For example, a routine blood test can detect anemia, infection and other problems; a biochemical index test can diagnose diseases such as diabetes and hyperlipidemia; and an immunological index test can detect autoimmune diseases.

3. Determine the severity of the disease

For a disease that has been diagnosed, blood tests can also help doctors determine the severity of the disease. For example, for an anemic patient, a blood test can help doctors understand the degree and type of anemia; for a diabetic patient, a blood sugar test can help doctors understand their blood sugar control status and adjust their treatment plan.

4. Monitoring treatment effects

During the treatment process, blood tests are also an important means of monitoring the treatment effect. By regularly testing relevant indicators in the blood, doctors can understand the patient's treatment effect and adjust the treatment plan in time. For example, for cancer patients, blood tests for tumor markers can help understand the changes in their condition and the treatment effect; for patients with cardiovascular diseases, blood lipid tests can help understand whether their blood lipid levels are under control.

4. Precautions for blood test

Although blood tests are of great significance to physical health, you should also pay attention to the following points when conducting blood tests:

1. Fasting examination

Some blood tests require fasting, such as blood sugar, blood lipid and other biochemical index tests. Therefore, before these tests, patients need to follow the doctor's advice and fast for a period of time in advance.

2. Avoid strenuous exercise

Before blood is drawn, patients should avoid strenuous exercise to avoid affecting the composition and indicators in the blood. If strenuous exercise is required, they should rest for a while after exercise before blood is drawn.

3. Stay relaxed

When drawing blood, patients need to stay relaxed to avoid tension or fear that may cause blood vessel constriction and increase the difficulty of drawing blood. They can relieve tension by taking deep breaths and relaxing their muscles.

4. Pay attention to the care after blood drawing

After blood is drawn, patients need to pay attention to the care of the blood drawing site. Avoid pressing or rubbing the blood drawing site to avoid bleeding or infection. At the same time, pay attention to keeping the blood drawing site clean and dry.

5. Misunderstandings about blood tests

During the blood test, patients may have some misunderstandings. Here are some common misunderstandings and explanations:

1. Myth 1: Drawing blood can harm your body

In fact, the amount of blood drawn for blood tests is very limited, usually ranging from a few milliliters to tens of milliliters. This amount of blood is tolerable for the human body and will not cause harm to the body. On the contrary, blood tests can help us detect diseases in a timely manner and take appropriate treatment measures to protect our health.

2. Myth 2: The more frequent the blood tests, the better

Although blood tests are important for physical health, it does not mean that the more frequent the better. Frequent blood tests will not only increase the financial burden and psychological pressure of patients, but may also cause unnecessary damage to the body. Therefore, when conducting blood tests, the frequency of the tests should be reasonably arranged according to the doctor's advice and actual conditions.

3. Myth 3: Blood tests can replace other tests

Although blood tests can reflect the health status of multiple systems in the human body, they cannot replace other examination methods. For example, for certain diseases such as tumors and cardiovascular diseases, in addition to blood tests, other examination methods such as imaging examinations and pathological examinations are also needed to confirm the diagnosis.

In short, blood tests are one of the commonly used examination methods in hospitals. Their purpose is to evaluate the health status of the human body by detecting various components and indicators in the blood. Blood tests can comprehensively evaluate health status, diagnose diseases, determine the severity of illnesses, and monitor treatment effects. When conducting blood tests, patients need to pay attention to fasting examinations, avoid strenuous exercise, stay relaxed, and pay attention to post-blood care. At the same time, misunderstandings and misconceptions about blood tests should be avoided. Through scientific and reasonable blood tests, we can detect diseases in time and take appropriate treatment measures to protect our health. Therefore, when the doctor requires a blood test, we should actively cooperate and follow the doctor's instructions for the examination.

Author: Ou Chaozhu Laboratory of Yingli Central Hospital, Leizhou City