Lactoferrin test: What do increased lactoferrin values in the stool mean?

For gastrointestinal complaints such as abdominal pain, nausea, or diarrhea a fecal lactoferrin test can provide important information for diagnosis.

Lactoferrin is a protein that can be detected in the stool during an inflammation in the intestine. Various diseases can hide behind such an inflammation, so an exact diagnosis cannot be made from an increase in the value alone.

What is lactoferrin?

lactoferrin is a protein that can bind iron to itself and acts against harmful bacteria. It is found in different body fluids, for example, in tears, saliva, and breast milk.

Certain white blood cells of the immune system (neutrophil granulocytes) contain a particularly large amount of lactoferrin. During a defense response, these immune cells release the lactoferrin. Then it helps fight harmful bacteria by absorbing the iron that the bacteria need to survive.

When does my doctor test lactoferrin in the stool?

A determination of the lactoferrin value in the stool is carried out if there is a suspicion of a currently occurring inflammation in the intestine or if an inflammation is to be excluded.

By determining lactoferrin in the stool, an inflammatory bowel disease (such as ulcerative colitis or Crohn's disease) can be distinguished from non-inflammatory bowel symptoms (such as irritable bowel syndrome). In both diseases, patients usually have symptoms similar to abdominal pain or diarrhea.

In irritable bowel syndrome, however, the value is usually not increased, while an increase in lactoferrin may indicate chronic inflammatory bowel disease.

Monitoring the lactoferrin values is also particularly suitable for long-term control of an already diagnosed chronic inflammation of the intestine. An increase in lactoferrin speaks for a current inflammatory flare-up of the chronic disease. In this way it can be assessed how well an anti-inflammatory treatment is working.

Is the lactoferrin level also tested in infants and children?

In children, the diagnosis of inflammatory bowel diseases is often made late because the complaints are non-specific and the examinations place a burden on the child.

A test for lactoferrin in the stool is therefore very suitable for children. It delivers** early signs of inflammatory bowel disease,** without unnecessarily stressful examinations. As with adults, measuring lactoferrin can also help children with the long-term control of a chronic inflammatory disease.

Since lactoferrin is present in breast milk, the lactoferrin test is not suitable for the examination of children who are breastfeeding. **The child consumes lactoferrin through breast milk, it enters the intestine and is excreted in the stool. The lactoferrin level is then increased even though there is no inflammation. Therefore, when doing a stool examination in childhood **it must always be indicated whether the child is breastfed.

How can one have the lactoferrin value examined?

If there are symptoms of the gastrointestinal tract such as diarrhea, abdominal pain or nausea, a stool sample can be given to the family doctor, for example. For this you get a container to be filled with a stool sample. Lactoferrin is very stable, so the sample does not need to be stored in a refrigerator.

The doctor's office sends the sample to a laboratory that gives the sample a substance that binds to the lactoferrin (lactoferrin antibody) and marks it in color. The strength of the color then indicates the amount of lactoferrin present. The stronger the color, the more lactoferrin was present in the sample. This test is called the ELISA test.

What is a normal lactoferrin level?

The amount of lactoferrin in the stool is given in micrograms (µg) lactoferrin per gram (g) stool.

There is no such thing as low lactoferrin in the stool. All values below 7.5 μg / g indicate that there is no inflammation in the intestine.

What does an increase in lactoferrin in the stool mean?

An increase in the lactoferrin value in the stool speaks for an inflammation in the intestine. With inflammation, white blood cells enter the intestine to fight possible pathogens. Lactoferrin is released into the intestine by these immune cells and the lactoferrin value in the stool increases.

An increase in lactoferrin cannot be attributed to a specific illness. The lactoferrin value is increased in both current infections and chronic intestinal inflammation. Therefore, lactoferrin is a non-specific marker for inflammation in the intestine.

What causes an increase in lactoferrin in the stool?

Since lactoferrin is a non-specific marker for inflammation, all symptoms need to be inquired about and further examinations carried out to make a diagnosis.

The following diseases can be a cause of the increase in lactoferrin in the stool:

Increased lactoferrin: what to do now?

Since an increase in lactoferrin alone does not allow an accurate diagnosis, further investigations should be carried out:

Stool examination for pathogens

Typical pathogens **that cause a gastrointestinal infection **virus (for example noroviruses or rotaviruses) and bacteria (for example Salmonella or Shigella). The pathogens are often transmitted via poorly washed hands, for example when preparing food.

Blood analysis

Signs of inflammation can also be found in the blood, which help to better assess the disease. These are also non-specific markers of inflammation, so that no exact diagnosis follows.

Ultrasound

With a Ultrasound examination of the abdomen, **changes to the organs **can be recognized without having to carry out a stressful intervention. Some diseases can lead to typical changes in an organ that can be detected using ultrasound.

X-ray examination

In some cases, such changes can also be found in an X-ray image. To do this, you swallow a paste before the X-ray with a substance that makes the digestive organs more visible in the X-ray image (barium sulfate).

Colonoscopy

A colonoscopy is an exact but stressful examination. If no pathogens are found, it helps to find the cause of the symptoms. A tube-like instrument (endoscope) is inserted into the intestine. A camera enables an examination of the intestinal mucosa. Inflammation, bleeding, tumor precursors, and tumors can be found and examined. A piece of tissue is taken from conspicuous areas in the intestine and analyzed. A more precise diagnosis can then be made from the results.

In this way, one can, for example, distinguish between chronic inflammatory bowel diseases Crohn's disease and ulcerative colitis.

What does a normal lactoferrin value mean?

If gastrointestinal symptoms exist and the lactoferrin test is negative, inflammation is probably not responsible for the symptoms.

In this case non-inflammatory bowel disease should be considered. This includes food intolerances to gluten or lactose and irritable bowel syndrome.

If there is only a slight increase in lactoferrin in the stool, it cannot be said with certainty whether there is inflammation or not. In this case further examinations can help to find out the cause of the symptoms.