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Preparing for a Blood Test: Things You Should Do to Get the Most Accurate Results

Medically Approved by Dr. Edward Salko

Table of Contents

This article is Medically Approved by Dr. Edward Salko

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Taking a blood test can be as simple as going to the laboratory or ordering the test online.

However, if you wish to have the most accurate results, you have to perform specific preparations.

As much as we would like to assume that blood tests are completely precise all the time, some conditions or mistakes could tamper with the analysis results.

In the field of laboratory diagnostics, medical errors are prevented as much as possible. And in the effort to keep the process accurate 100% of the time, the patient’s preparation prior to the blood test is reinforced.

Preparing for a blood test is all about conditioning. Our body produces chemicals that may disrupt the testing process. Hence, specific instructions prior to testing should be followed by all means. Otherwise, medical technicians may encounter problems analyzing your sample, or the result may be erroneous altogether.

If you are planning to take a blood test anytime soon, then you have landed on the right page.

In this article, we will go into the critical preparations you will need to do for specific blood tests. Let’s dive right in.

Do All Blood Tests Need a Special Preparation?

No, not all types of blood tests require special preparation. Most standard blood tests like CBC (Complete Blood Count) do not need strict preparation. You can take them without emptying your stomach or avoiding specific activities.

However, blood tests that do require special preparations need to be taken seriously. All instructions have to be followed as religiously as possible.

How Would I Know If a Blood Test Needs Special Preparations?

If you are wondering whether the blood test will require special preparations, the best thing you can do is ask your doctor.

Furthermore, the medical technologist or phlebotomist will provide you with the instructions prior to collecting the specimen.

Likewise, if you’re ordering a blood test online, the requirements are listed or expressed on the same page as the test kit.

For example, here at Personalabs, you can check the required preparations, such as fasting, under the “Special Notes” section.

Standard Preparation for Particular Blood Tests


Some blood tests will require time before and after analysis. This is true for several diagnostic screening that requires an unaltered chemical composition or immune reactions.

Here are the common preparations you may encounter for specific blood tests to give you a clearer picture.

What To Do?

1. Fasting

Fasting is a common requirement for a number of blood tests. It has to be performed, typically 8-12 hours, before the procedure.

Your doctor will instruct you to take the test with an empty stomach which means that you have to skip all types of food and beverages within the given timeframe. Nonetheless, you are allowed to drink water. 

Some blood tests require fasting because macromolecules found in food such as fats, proteins, carbohydrates, and minerals can significantly affect the levels of the markers or chemicals measured in the blood.

Here are some of the standard blood tests that need fasting:

  1. Blood Glucose Test
  2. Liver Enzyme Assay Test
  3. Renal Function Panel Blood Test
  4. Lipid Screening Blood Test
  5. Basic Metabolic Panel
  6. Lipoprotein Blood Test

2. Testing at specific times of the day 

Some tests generate the most optimum results if taken during the morning compared to any other time of the day. This is because our body secretes certain substances in larger quantities at specific times of the day.

These tests include hormones like FSH (follicle-stimulating hormone), estradiol, cortisol, growth hormone, and prolactin. 

However, you can still take the blood test any time of the day, but it is during the morning that accuracy peaks higher.  

3.  Conditioning your mind to relax

Staying calm during a blood test is vital to get the right results. 

When you are stressed out and anxious, you activate your “fight or flight response.” Your heart rate increases along with your blood pressure, and you release more cortisol. In some forms of blood tests, this could have an effect on the analysis of the sample.

Nonetheless, if you are frightened of blood tests, you’re definitely not alone. Many people fear medical procedures, especially those involving needles. 

Likewise, others are afraid of seeing blood firsthand. If you are apprehensive about taking blood tests due to these fears, you must find the right strategy to attain a relaxed state of mind. 

You can ask someone to accompany you. You can also listen to music, focus on your breathing, and ask for numbing creams if necessary. 

What To Avoid?

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1.   Specific foods and drinks

For some blood tests, specific foods and beverages can interfere with the results. Caffeine is a common substance that most blood tests limit or prohibit prior to the procedure. This can be linked with the fact that caffeinated drinks can be diuretic and could have a dehydrating effect.

2.   Certain medications

Drugs can have critical effects on the blood analysis results. Hence, patients are often requested to skip medications such as antidepressants, antipsychotics, antibacterial drugs, and contrast media before taking the test.

3.    Alcoholic drinks

Blood tests that require fasting are strict with avoiding alcohol intake prior to the procedure. Alcohol has a substantial impact on the levels of sugars and fats in the blood. If you neglect this requirement, you may end up with an erroneous blood test reading.

4.   Smoking

According to a study published at the ATVB (Arteriosclerosis, Thrombosis, and Vascular Biology) Journal, smoking can elevate white blood cells along with hemoglobin and hematocrit. Cigarettes are also known to raise blood pressure and glucose.

5.   Massage Therapy and Physiotherapy

A whole-body massage and other forms of physiotherapy can alter your blood pressure. Likewise, based on a study published in PubMed, they can elevate certain enzymes, hormones, and other hematological parameters.

6.   Stressful or Physical Activities

If you performed strenuous or stress-inducing activities prior to testing, physiological chemicals you secrete might go beyond or below your body’s average level. 

One example is the hormone cortisol. With cortisol, you will have to make sure that you are relaxed so the reading will be accurate to your condition.   

How to Get Blood Tests Online?

Ordering a blood test online is relatively easy.

Additionally, these tests come with instructions so you can perform the special preparations needed for accurate results.

If you’re looking for any blood test needed for laboratory diagnostics or treatment monitoring, then look no further, as Personalabs will readily help you in every step of the process. Simply create an account and explore lab tests without the hassle.

The Bottom Line

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Mistakes in blood tests nowadays are often linked to human error. Years of designing and refining blood testing procedures, kits, and panels secured the accuracy of the tools used in the process.

Besides, medical technologists and phlebotomists perform the collection and analysis of the samples meticulously.

While all these actions are done with care, the test results can be jeopardized if the patient fails to follow the instructions before the testing proper.

Therefore, you must always bear in mind what special preparations you need to make if you take a blood test. Check on the special notes and instructions so you can be appropriately guided.

Want to take the most convenient way of getting tested? Why not order your blood test at Peronalabs. All the information you need about the test, including the special preparations required, is provided to ensure accurate results.

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