UV spectroscopy is a method in which ultraviolet light (UV light) is used to investigate how substances absorb this light. UV light is invisible to our eyes and has a shorter wavelength than normal light. Many substances – for example proteins, DNA or medicines – absorb this light in a very specific way. The pattern of how much light they absorb and at what wavelength is like a fingerprint: it reveals which substance it is and how much of it is there.

Imagine shining a flashlight through a colored liquid: depending on the color, more or less light comes through. UV spectroscopy does something similar, only more precise and with invisible light. In laboratory medicine, this is used to analyze substances in blood, urine or other samples.

How does it work?

The technique is actually quite simple. You take a sample – such as blood serum or a dissolved tablet – and fill it into a small, transparent chamber known as a cuvette. Then a device called a spectrophotometer sends UV light through the sample. On the other side, a detector measures how much light passes through. Substances in the sample absorb certain wavelengths of light and the device records this as a curve. This curve shows peaks at certain wavelengths – and these reveal what is inside.

For example, proteins in blood absorb UV light at a wavelength of around 280 nanometers. If you know how much light is absorbed, you can even calculate how much protein is in the sample. The whole process runs automatically and only takes a few minutes.

Why is UV spectroscopy important in laboratory medicine?

UV spectroscopy is a real all-rounder in laboratory medicine in Germany. It helps with many tasks:

• Diagnosis of diseases: Doctors can use UV spectroscopy to measure substances in the blood that indicate problems – such as too much bilirubin in the case of jaundice or enzymes in the case of liver damage. This is quick and accurate.
  
• Medication control: laboratories check whether tablets or syringes contain the right amount of active ingredient. UV spectroscopy shows whether everything is correct before it is sent to patients.
  
• Research: Scientists use the method to develop new tests or to understand how diseases develop – for example through changes in DNA, which absorbs UV light differently.

A major advantage: the method is cheap, fast and only requires tiny amounts of samples. It also does not damage the sample, unlike some chemical tests. In Germany, where laboratories have high standards, it is an integral part of daily work.

How does this work in practice?

Let’s assume that a doctor wants to know whether a patient has enough protein in their blood – for example, if malnutrition is suspected. He draws blood, which is sent to the laboratory. There, the serum (the liquid part of the blood) is filled into the cuvette. The spectrophotometer measures how much UV light disappears at 280 nanometers. The value is compared with normal values – in adults, the protein content in serum is around 66 to 83 grams per liter. If it is too low, the doctor discusses this with the patient, perhaps with tips on nutrition.

The devices are so accurate that they can detect even the smallest differences. In Germany, laboratories have to be tested regularly so that the results are reliable everywhere – whether in Berlin or Munich.

What are the limits?

UV spectroscopy is great, but not perfect. If a sample contains many substances that absorb similar amounts of light, it gets tricky – the curves overlap and you have to separate the mixture first. It can also only measure substances that absorb UV light – other methods are needed for others. Nevertheless, it is a standard because it is so versatile.

Conclusion: a ray of hope for health

UV spectroscopy is like a detective with a UV lamp: it makes the invisible visible and helps to monitor health. It is indispensable in laboratory medicine in Germany – fast, accurate and inexpensive. Whether for blood tests, drug testing or research, it provides answers that help doctors and patients. A small beam of light with a big effect – science can be that simple.

Editorial office: X-Press Journalistenbüro GbR

Gender note. The personal designations used in this text always refer equally to female, male and diverse persons. Double/triple references and gendered designations are avoided for the sake of better readability ected.