Lactoferrin: What a Positive Test Means

What Is Lactoferrin?

Lactoferrin is a protein that binds iron in the body. It plays an important role in immune defense and inflammation control.

This biomarker is found in many body fluids, including blood, saliva, tears, breast milk, and stool. Lactoferrin helps limit bacterial growth by reducing free iron, which many pathogens need to survive. Because of this function, lactoferrin is often used as a marker of inflammation or infection, especially in the gut.

In medical testing, lactoferrin is most commonly used to help identify inflammatory conditions rather than functional digestive issues.

When Is Lactoferrin Testing Recommended?

Lactoferrin testing is usually ordered when inflammation or infection is suspected.

Common reasons include:

• Persistent diarrhea with no clear cause
• Chronic abdominal pain or bowel changes
• Suspected inflammatory bowel disease
• Monitoring known intestinal inflammation
• Differentiating inflammatory conditions from functional disorders
• Evaluating response to treatment in gut-related diseases

How Is Lactoferrin Testing Conducted?

Lactoferrin is most commonly measured through a stool test. A small stool sample is collected and analyzed in a laboratory.

The test looks for lactoferrin released by white blood cells in the intestines. High levels suggest active inflammation in the digestive tract. Blood testing is less common and usually reserved for specific clinical situations.

No fasting is required for stool lactoferrin testing. You may be asked to avoid certain supplements or testing during active infections, depending on your doctor’s guidance.

What Are the Normal Lactoferrin Levels?

Normal stool lactoferrin levels are typically reported as negative or low, meaning no significant intestinal inflammation is detected.

Some laboratories may provide a numeric range or a qualitative result.

Note: The units of measurement and the normal ranges can differ depending on the laboratory and the specific methods used.

What Does a Positive Lactoferrin Result Mean?

A positive lactoferrin result means there is active inflammation in the intestines. It shows that white blood cells are present in the gut lining.

Possible causes include:

• Inflammatory bowel disease: Chronic inflammation damages the intestinal wall and triggers immune activity.
• Bacterial intestinal infections: Infections cause the immune system to release lactoferrin.
• Colitis: Inflammation of the colon raises lactoferrin levels.
• Severe intestinal inflammation: Any condition that injures intestinal tissue can lead to a positive result.

Recommendations

• Follow up with additional testing if recommended.
• Monitor symptoms such as diarrhea, abdominal pain, or blood in the stool.
• Stay hydrated and support gut health with balanced nutrition.
• Work with your doctor to identify and manage the underlying cause.

Which Specialist Should You Consult?

A gastroenterologist is the main specialist for abnormal lactoferrin results.

Depending on your symptoms, you may also be referred to:

• An infectious disease specialist for suspected infections
• A primary care physician for initial evaluation and follow-up