Lactoferrin

Q: How does fecal lactoferrin compare to fecal calprotectin?

Both are neutrophil-derived proteins used to detect intestinal inflammation, and their clinical utility is very similar. Calprotectin is more widely studied and used globally, with more established reference ranges and cutoff values. Lactoferrin may have slightly higher specificity for IBD in some studies and is more stable at room temperature. In practice, either test can be used to distinguish IBD from IBS, monitor disease activity, and predict relapse. The choice often depends on local laboratory availability and physician preference.

Q: Is lactoferrin in breast milk the same as fecal lactoferrin?

The protein itself is the same, but the source and clinical context differ entirely. Breast milk contains very high concentrations of lactoferrin (approximately 1–2 g/L in mature milk, even higher in colostrum) produced by mammary gland epithelial cells. This lactoferrin provides antimicrobial and immune protection to the nursing infant. Fecal lactoferrin, measured clinically, comes from neutrophils that have migrated into the inflamed intestinal wall. In breastfed infants, some breast milk lactoferrin may appear in stool, which should be considered when interpreting fecal lactoferrin results in this population.

Q: Can medications affect fecal lactoferrin levels?

Yes, NSAIDs (ibuprofen, naproxen, aspirin) can cause intestinal mucosal inflammation and neutrophil infiltration, leading to elevated fecal lactoferrin even in the absence of IBD. Patients should ideally stop NSAIDs for 2 weeks before testing. Proton pump inhibitors (PPIs) may also mildly elevate levels. Immunosuppressive medications used to treat IBD (such as azathioprine, methotrexate, or biologics like infliximab) typically reduce fecal lactoferrin by controlling intestinal inflammation—this is the desired therapeutic effect and a sign of treatment success.

Gastrointestinal

Última revisão: 7 de abril de 2026. Abordagem de fontes: contexto padrão de interpretação laboratorial, material médico de referência e orientações clínicas ou de saúde pública quando relevantes.

O que é Lactoferrin?

Lactoferrin is an iron-binding glycoprotein found in high concentrations in neutrophil granules, breast milk, tears, saliva, and mucosal secretions. When intestinal inflammation occurs, activated neutrophils infiltrate the gut wall and release lactoferrin into the intestinal lumen, where it can be measured in stool samples as fecal lactoferrin. This protein is remarkably stable and resistant to proteolytic degradation, remaining detectable in stool samples for up to 5 days at room temperature, making it a reliable and practical biomarker.

Fecal lactoferrin serves a clinical role similar to fecal calprotectin as a non-invasive marker of intestinal inflammation. It is particularly useful for distinguishing inflammatory bowel disease (IBD) from functional gastrointestinal disorders like irritable bowel syndrome (IBS). Beyond its role as an inflammatory marker, lactoferrin has intrinsic antimicrobial properties—it sequesters iron from pathogenic bacteria (iron is essential for bacterial growth), directly damages bacterial cell membranes, and modulates the immune response. Lactoferrin is also a major component of breast milk, providing innate immune protection to newborns.

Por que isso importa

Fecal lactoferrin is a highly sensitive and specific marker for neutrophilic intestinal inflammation. Its clinical significance parallels fecal calprotectin—it effectively distinguishes IBD from IBS, reducing unnecessary colonoscopies, and serves as a monitoring tool for disease activity in established IBD. Lactoferrin levels correlate with endoscopic and histological disease severity in both Crohn's disease and ulcerative colitis. The test is particularly valuable in clinical settings where calprotectin testing is unavailable, and some studies suggest lactoferrin may be more specific than calprotectin in certain clinical scenarios. As a natural antimicrobial protein, lactoferrin also reflects the gut's innate immune defense status.

Faixas de referência normais

Grupo	Faixa	Unidade
Adults (negative)	<7.25	mcg/g
Positive (inflammation likely)	≥7.25	mcg/g

As faixas de referência podem variar entre laboratórios. Sempre compare seus resultados com as faixas fornecidas pelo seu local de exame.

O que significam níveis altos de Lf

Causas comuns

Inflammatory bowel disease (Crohn's disease, ulcerative colitis)
Bacterial gastroenteritis (Salmonella, Shigella, Campylobacter)
Clostridioides difficile infection
Colorectal cancer
NSAID-induced enteropathy
Diverticulitis
Necrotizing enterocolitis (in neonates)

Possíveis sintomas

Diarrhea (often bloody or mucus-containing)
Abdominal pain and cramping
Fever
Urgency and tenesmus
Weight loss and fatigue
Rectal bleeding

O que fazer: Elevated fecal lactoferrin indicates significant intestinal inflammation and warrants further workup. Colonoscopy with biopsies is typically indicated to determine the cause. Rule out infectious etiologies with stool cultures and C. difficile testing. For known IBD patients, elevated lactoferrin during remission may signal subclinical inflammation or impending relapse, warranting treatment review with your gastroenterologist. Discontinue NSAIDs if applicable and retest.

O que significam níveis baixos de Lf

Causas comuns

Normal finding—indicates no significant neutrophilic intestinal inflammation
Irritable bowel syndrome (lactoferrin is typically normal)
Functional dyspepsia
IBD in complete mucosal remission

Possíveis sintomas

No symptoms—negative fecal lactoferrin is the expected healthy result

O que fazer: A negative fecal lactoferrin result is reassuring and strongly argues against active inflammatory bowel disease. If gastrointestinal symptoms persist, consider evaluation for functional GI disorders, food sensitivities, celiac disease, or small intestinal bacterial overgrowth. For IBD patients in remission, a negative lactoferrin supports mucosal healing and adequacy of current therapy.

Quando o exame de Lf é recomendado?

To differentiate IBD from IBS in patients with chronic GI symptoms
When evaluating chronic diarrhea of unknown cause
To monitor disease activity in established IBD
To assess mucosal healing after IBD treatment changes
When infectious colitis is suspected
As an alternative to fecal calprotectin when unavailable

Perguntas frequentes

Both are neutrophil-derived proteins used to detect intestinal inflammation, and their clinical utility is very similar. Calprotectin is more widely studied and used globally, with more established reference ranges and cutoff values. Lactoferrin may have slightly higher specificity for IBD in some studies and is more stable at room temperature. In practice, either test can be used to distinguish IBD from IBS, monitor disease activity, and predict relapse. The choice often depends on local laboratory availability and physician preference.

The protein itself is the same, but the source and clinical context differ entirely. Breast milk contains very high concentrations of lactoferrin (approximately 1–2 g/L in mature milk, even higher in colostrum) produced by mammary gland epithelial cells. This lactoferrin provides antimicrobial and immune protection to the nursing infant. Fecal lactoferrin, measured clinically, comes from neutrophils that have migrated into the inflamed intestinal wall. In breastfed infants, some breast milk lactoferrin may appear in stool, which should be considered when interpreting fecal lactoferrin results in this population.

Yes, NSAIDs (ibuprofen, naproxen, aspirin) can cause intestinal mucosal inflammation and neutrophil infiltration, leading to elevated fecal lactoferrin even in the absence of IBD. Patients should ideally stop NSAIDs for 2 weeks before testing. Proton pump inhibitors (PPIs) may also mildly elevate levels. Immunosuppressive medications used to treat IBD (such as azathioprine, methotrexate, or biologics like infliximab) typically reduce fecal lactoferrin by controlling intestinal inflammation—this is the desired therapeutic effect and a sign of treatment success.

Biomarcadores relacionados

fCalCalprotectin ALBAlbumina

Leitura relacionada

Condições

Síndrome do intestino irritável (SII) →

Referências e abordagem de revisão

As páginas do glossário de biomarcadores são explicações educativas e devem ser interpretadas junto com as faixas de referência e observações fornecidas pelo seu laboratório e pelo seu médico. Para conhecer nossos padrões editoriais e processo de revisão, veja nossa Política editorial e a nossa revisão de conteúdo.

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Aviso médico: Estas informações são apenas educativas e não substituem orientação, diagnóstico ou tratamento médico profissional. As faixas de referência podem variar entre laboratórios. Sempre converse com seu profissional de saúde sobre a interpretação dos seus resultados específicos.