Blood test

The possible cause of many physical symptoms and conditions can often be identified through blood tests. Blood tests also help determine how effectively a medication is working. To obtain this information, blood must first be drawn.

Where can you have blood drawn?

A blood test is requested by your GP or a medical specialist. The person drawing the blood will know how much blood is required and how many tubes are needed. The laboratory technician who examines the blood later will also know what to analyze. The requesting doctor will specify whether you need to fast and whether you should temporarily stop taking any medications. If fasting is required, you should avoid eating or drinking for 8 hours before the test.

Blood is drawn at designated phlebotomy points, which are often located at GP practices or hospitals. Many other phlebotomy locations are also available in the area. Some locations offer early morning or evening appointments, which can be convenient if you need to fast or prefer to go after work. In some cases, an appointment is necessary, and this can often be scheduled online. Ask for a location near you.

How does blood collection work?

The phlebotomist verifies that the person named on the request form matches the individual present for the blood draw. The phlebotomist prepares the appropriate tubes and labels them with a sticker containing the patient’s details. If you are afraid of needles, inform the staff immediately so they can accommodate your needs. You will always be seated during the procedure.

A tight band, called a tourniquet, is placed around your upper arm. This, combined with clenching your fist, causes the vein to swell slightly, making it easier to locate and access. The puncture site is then disinfected with alcohol, and a hollow needle is inserted into the vein, usually in the elbow crease. This may cause brief discomfort, but it is short-lived. The tubes slowly fill with blood, and if multiple tubes are needed, they are changed as necessary.

The tubes contain an anticoagulant to keep the blood liquid, which is essential for accurate testing. Once enough blood is collected, the needle is removed. Pressure is applied to the puncture site with a swab to stop the bleeding, and a plaster is applied. Occasionally, a bruise may develop afterward, but this is harmless and typically fades within a few days.

The tubes are gently shaken to mix the blood with the anticoagulant, either by hand or with a special device. The blood is then sent to the laboratory for analysis.

What can be detected in a blood test?

Blood contains various components, including blood cells, nutrients, building materials, and waste products. Analyzing the blood’s composition provides important information about your health, organ function, and the effectiveness of treatments.
Examples of what can be measured in a blood test include:

• Inflammation markers (indicating inflammation somewhere in the body).
• Iron levels.
• Blood sugar levels.
• Proteins.
• Waste products.
• Medication levels.
• Hormone levels.
• Antibodies against specific diseases.
• Bacteria and viruses.
• Toxins, such as alcohol and drugs.

The result

The results of the blood test are usually available within a few days and can be obtained from your GP or viewed online. Your doctor will discuss the results with you. To determine whether any values are abnormal, the doctor compares your results to reference values.

Reference values are established by measuring a large group of healthy individuals and calculating an average. If your values fall above or below this range, they are considered abnormal. For example, a normal value might be between 5 and 10; values outside this range would be flagged as abnormal.

The doctor combines the blood test results with any other tests and your reported symptoms. Based on this information, the doctor will decide on the next steps, which may include a referral to a specialist, a change in medication, or no change at all. This decision is always made in consultation with you.