Is fasting required for blood tests?

Generally speaking, you do not need to fast for a blood test and you can do it at any time. Drinking water has relatively little effect on blood tests. However, you need to understand that sometimes other examinations may be needed, which require fasting. So when you are unsure, if other examinations are needed, it is best to fast first to avoid affecting the entire examination process. Avoid affecting time and affecting inspection efficiency.

What is a blood test?

A routine blood test is a basic physical examination item in pre-pregnancy check-ups. Its significance lies in that it can detect early signs of many systemic diseases, diagnose whether anemia is present, whether there is a blood system disease, and reflect the hematopoietic function of the bone marrow.

In the results of routine blood tests, infectious diseases usually cause changes in the number and classification of white blood cells: in anemia, the test values ​​of hemoglobin or red blood cells will decrease; a decrease in platelets will lead to easy bleeding or difficulty in stopping bleeding, while an increase in platelets will increase the possibility of thrombosis; in addition, some tumors and reflex diseases can also cause changes in some values ​​of routine blood tests.

Therefore, a routine blood test can help identify potential health problems early on. Once discovered, they need to be cured before pregnancy can take place in order to achieve the goal of eugenics.

Routine blood test

1. Determine whether there is other bacterial infection. If the total white blood cell count and neutrophil count in the peripheral blood of a hepatitis B patient are elevated, attention should be paid to whether there is a concurrent bacterial infection.

2. Determine whether there is hypersplenism. Patients with severe hepatitis B and cirrhosis usually have hypersplenism. If the total white blood cell count and platelet count in the peripheral blood of HBV-infected patients are significantly reduced, hypersplenism should be considered and attention should be paid to checking for cirrhosis.

3. Determine whether antiviral treatment is needed. Current antiviral drugs all have varying degrees of bone marrow suppression, among which interferon has a particularly significant inhibitory effect on the bone marrow. Therefore, blood routine tests should be performed regularly before and during antiviral treatment.

4. Determine whether aplastic anemia exists. If a person infected with hepatitis B virus has an unexplained decrease in complete blood count, aplastic anemia should be considered.

Things to note when doing a blood test

1. Clean the part where blood is to be collected, which is usually the earlobe, middle finger or ring finger tip. Wait until the part where blood is to be collected is dry before collecting blood. On cold days, you can rub the area to warm it up before drawing blood.

2. You should be on an empty stomach before a routine blood test, but fasting is not as simple as skipping breakfast. You should avoid eating greasy food the night before the examination, and you should fast after 8 o'clock. If you still have a midnight snack at 12 o'clock, you will not be able to ensure that you are on an empty stomach when your blood is drawn. On the morning of the physical examination, it is recommended to drink only boiled water.

3. On the day of the physical examination, it is best to wear clothes with loose sleeves to facilitate rolling up the sleeves when drawing blood from the vein; clothes should be clean to prevent pinhole infection.

4. After blood collection, straighten your forearm and use your other hand to press the hemostatic cotton ball tightly for at least 5 minutes. Do not bend your elbow to stop the bleeding, and do not twist the cotton ball to avoid subcutaneous bruising. If there is bruising around the stye, you can apply hot compress after 24 hours. To avoid infection, do not let the needle hole get wet for 24 hours.