Are calprotectin and lactoferrin equivalent screening tests for inflammatory bowel disease?

Background: Lactoferrin and calprotectin are frequently ordered stool tests used to screen patients for inflammatory bowel disease versus functional bowel disease. Current guidelines recommend using either one to screen for inflammation in the GI tract; however, little information is available on how these 2 assays compare and their use in different clinical specialties.

Methods: We compared order patterns for lactoferrin and calprotectin using data from a large reference laboratory over a 10-y period (2009-2019). We also studied the concordance of lactoferrin and calprotectin in cases where both tests were ordered concurrently. Finally, we reviewed the records at a university hospital to determine which clinicians ordered each test and the indications associated with orders.

Results: Orders for calprotectin are increasing relative to lactoferrin. The relative proportion of calprotectin orders have increased from 60% to nearly 90% over the past decade. Results for lactoferrin and calprotectin show concordance (90%). Calprotectin and lactoferrin are ordered by different clinical specialties for different indications. Calprotectin is most often ordered by gastroenterologists in the context of abdominal pain. Lactoferrin is most often ordered by primary care providers in the context of acute diarrhea.

Conclusion: Lactoferrin and calprotectin are not treated as equivalent tests by clinicians.