What is being tested?
Lactoferrin is protein released by a type of white blood cell called a neutrophil. When there is inflammation in the digestive tract, neutrophils are attracted to the area and release lactoferrin, increasing the level of the protein in the stool. This test measures the level of lactoferrin in stool as a way to detect inflammation in the intestines.
Intestinal inflammation is associated with inflammatory bowel disease (IBD) and with some bacterial infections of the digestive tract, but it is not associated with many other disorders that affect bowel function and cause similar symptoms. Lactoferrin can be used to help distinguish between inflammatory and non-inflammatory conditions.
IBD is a group of chronic disorders characterized by swollen and damaged tissues in the lining of the intestinal tract. The cause of IBD is not known, but these diseases are thought to be due to an autoimmune process that has been triggered by a genetic predisposition, a viral illness, and/or an environmental factor. The most common inflammatory bowel diseases are Crohn disease (CD) and ulcerative colitis (UC).
People affected by IBD typically have flare-ups of active disease that alternate with periods of remission. During a flare-up, a person may experience frequent bouts of watery and/or bloody diarrhea, abdominal pain, weight loss, and fever. Between these flare-ups, symptoms frequently subside. Many people may go through extended periods of remission between flare-ups. Lactoferrin testing can be useful in monitoring disease activity.
How is the sample collected for testing?
A stool sample is collected in a clean container provided by the laboratory. This sample should be uncontaminated by urine or water.
How is it used?
Lactoferrin is a stool (fecal) test that is used to detect inflammation in the intestines. Intestinal inflammation is associated with, for example, some bacterial infections and, in people with inflammatory bowel disease (IBD), it is associated with disease activity and severity. The test may be ordered to distinguish between IBD and non-inflammatory disorders and to monitor IBD disease activity.
A health care practitioner may order a lactoferrin test to help investigate the cause of a person’s persistent watery or bloody diarrhea. The test may be ordered along with other stool tests, such as a stool culture to detect a bacterial infection, a test for ova and parasites (O&P), a stool white blood cell test, and/or a fecal occult blood test.
If a healthcare practitioner suspects inflammation, then blood tests that detect inflammation in the body, such as an ESR (erythrocyte sedimentation rate) and/or CRP (C-reactive protein), may also be ordered. Testing is performed both to help determine what is causing a person’s symptoms and to rule out conditions with similar symptoms. This means that additional blood and stool testing may be performed depending on the suspected causes.
If a person has been diagnosed with IBD, then a lactoferrin test may be ordered to monitor disease activity and to help evaluate its severity. For example, if a person has a moderately elevated lactoferrin, then testing may be repeated several weeks later to see if it has stayed moderately elevated, increased, or returned to normal.
A lactoferrin test may be ordered to help determine whether an endoscopy is indicated if IBD is suspected. A diagnosis of IBD is usually confirmed by performing an endoscopy (colonoscopy or sigmoidoscopy) to examine the intestines and by obtaining a small tissue sample (biopsy) to evaluate for inflammation and changes in tissue structures. This testing is invasive and is less likely to be necessary if inflammation is not present.
When is it ordered?
A lactoferrin test may be ordered when a person has symptoms that suggest that intestinal inflammation may be present and when a healthcare practitioner wants to distinguish between IBD and a non-inflammatory bowel condition.
Signs and symptoms of intestinal inflammation will vary from person to person and over time. They may include one or more of the following:
- Bloody or watery diarrhea
- Abdominal cramps or pain
- Weight loss
- Rectal bleeding
Testing for lactoferrin may be performed when a healthcare practitioner wants to determine whether an endoscopy (colonoscopy or sigmoidoscopy) is likely or less likely to be necessary.
When a person has been diagnosed with IBD, a lactoferrin test may be ordered whenever a flare-up is suspected, both to confirm disease activity and to evaluate its severity.
What does the test result mean?
An elevated lactoferrin level in the stool indicates that inflammation is likely present and active in the digestive tract but does not indicate either its location or cause. In general, the degree of elevation is associated with the severity of the inflammation. An endoscopy (colonoscopy or sigmoidoscopy) may be indicated as a follow-up test.
Increases in lactoferrin are seen with IBD but also with other inflammatory conditions, with intestinal bacterial infections, some parasitic infections, and with colon cancer.
In newly diagnosed people with IBD, concentrations of lactoferrin may be very high.
A low level of lactoferrin means that a bowel disorder is likely non-inflammatory. Examples of these include diarrhea due to viral digestive tract infections and irritable bowel syndrome (IBS). Unlike IBD, IBS does not cause inflammation. Rather, it causes cramp-like stomach pains and spasms with bouts of diarrhea and/or constipation. People with low lactoferrin results are less likely to require an endoscopy.
A moderate lactoferrin level may be seen in those with less active IBD. The result indicates that there is likely some inflammation present. If a repeat test shows that the lactoferrin has increased, then the person’s condition may be worsening.
Is there anything else I should know?
Lactoferrin is related to another stool test, calprotectin. Both are substances that are released by white blood cells in the stool and are associated with intestinal inflammation. Of the two tests, calprotectin has been the most extensively studied and it is ordered more frequently than lactoferrin. Usually one or the other will be ordered but not both.
A baby that is being breast-fed could potentially have a false-positive result because of lactoferrin present in the mother’s breast milk.
Should both a lactoferrin and a calprotectin test be done?
Current evidence suggests that there is not a significant benefit to performing both tests as they both detect intestinal inflammation.
Does it matter whether I have a lactoferrin or a calprotectin test?
Calprotectin has been more extensively studied and is ordered more frequently, but in general they are both thought to be useful tests.
What can I do to decrease my lactoferrin?
Lactoferrin is a reflection of intestinal inflammation and is not affected by lifestyle changes. If it is due to an infection, then it will most likely return to normal when the infection resolves. If it is due to inflammatory bowel disease, then it will rise and fall with disease activity.
How long will it take for test results?
That depends on the laboratory performing the test. This test is somewhat specialized and is not offered by all laboratories. The sample will likely be sent to a reference laboratory for testing and it may take several days before results are available.