Is a lactoferrin level of 11.5 considered high?

Is a Lactoferrin Level of 11.5 Very High?

Yes, a fecal lactoferrin level of 11.5 mg/g is elevated and indicates active intestinal inflammation, as it exceeds the diagnostic threshold of 7.25 mg/g used to detect moderate to severe endoscopic disease activity. 1

Understanding the Threshold

• The standard cutoff for elevated fecal lactoferrin is >7.25 mg/g, which corresponds to the commercial assay's positive/negative threshold 1
• At this cutoff, fecal lactoferrin demonstrates 83% sensitivity and 75% specificity for detecting moderate to severe endoscopic inflammation in inflammatory bowel disease 1
• Your level of 11.5 mg/g is approximately 1.6 times higher than the diagnostic threshold, placing it clearly in the elevated range

Clinical Significance by Symptom Severity

For patients with typical UC symptoms (frequent rectal bleeding and increased stool frequency):

• Elevated lactoferrin >7.25 mg/g has only a 3.7% false positive rate in this high pretest probability scenario 1
• This means your elevated level very likely reflects true moderate to severe endoscopic inflammation 1

For patients with mild symptoms (infrequent bleeding or moderately increased stool frequency):

• The false positive rate increases to 12.5% in this intermediate pretest probability scenario 1
• However, your level still strongly suggests active inflammation requiring further evaluation 1

For asymptomatic patients:

• Even in low pretest probability scenarios, elevated lactoferrin warrants investigation, though repeat testing in 3-6 months may be appropriate before proceeding to endoscopy 2, 3

Comparison to Normal Values

• Healthy controls have mean fecal lactoferrin levels of approximately 1.17-1.45 μg/mL (essentially <2 mg/g) 4, 5
• Patients with irritable bowel syndrome have similarly low levels around 1.27 μg/mL 5
• Active IBD patients demonstrate mean levels of 440-1125 μg/mL depending on disease type and severity 4, 5
• Your level of 11.5 mg/g falls well within the inflammatory range, though not at the extreme upper end seen in severe disease 4, 5

Important Clinical Caveats

Rule out confounding factors before attributing elevation solely to IBD:

• NSAID use within the past 6 weeks can elevate lactoferrin levels and should be documented 2, 3
• Enteric infections, particularly C. difficile, can cause marked lactoferrin elevation and must be excluded first 3, 6
• Different collection and processing methods can affect measurement accuracy 3

Consider discordant biomarker patterns:

• If fecal calprotectin is normal (<150 mg/g) but lactoferrin is elevated, this may reflect segmental disease that calprotectin misses 2, 3
• In this discordant scenario with mild symptoms, proceed with endoscopic assessment rather than empiric treatment adjustment 2, 3
• If asymptomatic with discordant markers, repeat both biomarkers in 3-6 months before endoscopy 2, 3

Recommended Next Steps

If you have moderate to severe symptoms (frequent bleeding, significant stool frequency increase):

• This elevated lactoferrin strongly indicates moderate to severe endoscopic activity 1
• Consider treatment adjustment based on biomarker elevation without routine endoscopy in this high pretest probability scenario 3

If you have mild symptoms:

• Proceed with endoscopic assessment to confirm inflammation before treatment changes 2, 3
• Monitor both lactoferrin and calprotectin to determine which correlates better with your disease activity 2, 3

If you are asymptomatic:

• Repeat biomarker testing in 3-6 months 2, 3
• Proceed to endoscopy only if lactoferrin remains elevated on repeat testing 2