Blood plasma is a fascinating component of our blood – and a key player in laboratory medicine. But what exactly is it and why is it so important for diagnoses and treatments?

Blood plasma makes up around 55 percent of our blood and is the liquid base in which the blood cells – red and white blood cells and platelets – float. It looks light yellow and consists of around 90 percent water. The rest is made up of important substances such as proteins, sugar, salts, hormones and vitamins. This mixture has many functions: It transports nutrients to the cells, helps with blood clotting, fights infections and keeps the body’s fluid balance in equilibrium. To examine blood plasma in the laboratory, blood is spun in a centrifuge – this separates the cells and the plasma remains.

In laboratory medicine, blood plasma is a kind of treasure chest full of information. Because it contains so many substances, doctors can use it to find out how your health is doing. For example, laboratories measure the proteins in plasma, such as albumin or globulins, to check whether the liver or kidneys are working properly. An albumin level that is too low could indicate liver disease, while certain globulins become conspicuous in the case of infections or autoimmune diseases. Blood sugar is also measured in the plasma – an important test for diabetes. And in the case of heart problems, specialists look for markers such as troponin, which appear in the plasma when the heart is damaged.

Blood plasma is also crucial for detecting infections. Antibodies that our immune system produces against viruses or bacteria float in the plasma. Laboratories can detect them, for example in tests for hepatitis, HIV or corona. Such analyses not only help with diagnosis, but also show whether someone is already immune or whether a vaccination has worked. Modern techniques such as mass spectrometry even make it possible to find tiny traces of pathogens or metabolic products in plasma – a huge step forward in early detection.

In addition to diagnostics, blood plasma also has a practical significance in medicine, which goes hand in hand with laboratory medicine. Donated plasma is used to produce medicines, for example for people with blood clotting disorders such as haemophilia or for patients with a weak immune system. Laboratories check in detail whether the plasma is safe and contains the right ingredients. Without these analyses, the production of such life-saving drugs would not be possible.

The importance of blood plasma in laboratory medicine therefore lies in its versatility. It is like a mirror of the body: almost every disease leaves traces in the plasma that laboratories can make visible. At the same time, it is a resource that is not only examined, but also used to help people. Without blood plasma, many diagnoses would be uncertain and therapies unthinkable – it is a silent hero of modern medicine that only really comes to life in the laboratory.

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