210. Clinical Utility of Fecal Lactoferrin in Determining Infectious Etiology of Diarrhea
Session: Poster Abstract Session: Diagnostics: Enteric Infection
Thursday, October 27, 2016
Room: Poster Hall
Background:

Fecal lactoferrin (FL), a marker of intestinal inflammation, is often ordered to evaluate patients presenting with diarrhea. Given the low prevalence of enteroinvasive infections among patients presenting with diarrhea, the utility of FL as a screening test is unclear. We examined the clinical utility of FL testing to predict the infectious etiology of diarrhea.

Methods:

All patients with a test order for FL (LEUKO EZ VUE, TECHLAB) at a tertiary care institution in 2015 were eligible for inclusion (n = 4917). Repeat tests (408), unresulted tests (5), or patients without at least one enteric pathogen (EP) stool test ordered within 7 days of their FL test (246) were excluded. Demographic, comorbid, and encounter-level data were retrospectively collected. EPs were classified as “inflammatory” or “non-inflammatory” based on prior literature. The sensitivity, specificity, positive and negative predictive values (PPV, NPV) of FL for EPs were determined.

Results: 

A total of 4273 patients with FL test results met criteria for study inclusion. Tests to detect “inflammatory” EPs performed in this cohort included 3488 bacterial stool cultures, 3486 Shiga toxin enzyme immunoassays (EIA), 3198 Campylobacter EIA, 3497 Clostridium difficile toxin gene PCR assays. Tests performed for “non-inflammatory” EPs included 1324 Cryptosporidium EIA, 1324 Giardia EIA, 1325 ova & parasite exams, and 7 norovirus PCR tests. A total of 2537 FL tests (59%) were positive and those patients were more likely to be older, male, and inpatients. Overall, FL was 81% sensitive and 43% specific for “inflammatory” EPs, but 55% sensitive and 42% specific for “non-inflammatory” EPs. The PPVs for “inflammatory” and “non-inflammatory” EPs were 16% and 1% respectively; the NPVs were 95% and 99% respectively. FL sensitivity for individual “inflammatory” EPs ranged from 76% for C. difficile to 100% for Shigella sp. FL sensitivity for “non-inflammatory” EPs ranged from 11% for ova & parasites detected by microscopy to 100% for norovirus.

Conclusion: 

The majority of FL tests ordered were positive and performed in conjunction with specific EP tests. Although FL was more sensitive for inflammatory than non-inflammatory pathogens, poor specificity and PPV limits the clinical utility of the test.

Hannah Wang, BS, Cleveland Clinic Lerner College of Medicine, Cleveland, OH, Abhishek Deshpande, MD, PhD, Department of Infectious Diseases, Cleveland Clinic, Cleveland, OH; Medicine Institute Center for Value-Based Care Research, Cleveland Clinic, Cleveland, OH, James Karichu, MT (ASCP), Laboratory Medicine, Cleveland Clinic, Cleveland, OH, Gary Procop, MD, FIDSA, Pathology and Laboratory Medicine, Cleveland Clinic, Cleveland, OH and Sandra S. Richter, MD, Department of Laboratory Medicine, Cleveland Clinic, Cleveland, OH

Disclosures:

H. Wang, None

A. Deshpande, None

J. Karichu, bioMerieux: Use their products for research , Research support
BD Diagnostics: Use their products for research , Research support

G. Procop, None

S. S. Richter, bioMerieux: Investigator , Research support
BD Diagnostics: Investigator , Research support

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