Verification of the fCAL turbo immunoturbidimetric assay for measurement of the fecal calprotectin concentration in dogs and cats

Abstract

The concentration of calprotectin in feces (fCal) is a clinically useful marker of chronic gastrointestinal inflammation in humans and dogs. No commercial assay is widely available to measure fCal in small animal medicine, to date. Thus, we verified the immunoturbidimetric fCAL turbo assay (Bühlmann) of fCal for canine and feline fecal extracts by determining linearity, spiking and recovery, and intra-assay and inter-assay variability. We determined RIs, temporal variation over 3 mo, and effect of vaccination and NSAID treatment. Observed:expected (O:E) ratios (x̄ ± SD) for serial dilutions of feces were 89–131% (106 ± 9%) in dogs and 77–122% (100 ± 12%) in cats. For spiking and recovery, the O:E ratios were 90–118% (102 ± 11%) in dogs and 83–235% (129 ± 42%) in cats. Intra- and inter-assay CVs for canine samples were ≤19% and ≤7%, and for feline samples ≤22% and ≤21%. Single-sample RIs were <41 μg/g for dogs and <64 μg/g for cats. With low reciprocal individuality indices, using population-based fCal RIs is appropriate, and moderate fCal changes between measurements (dogs 44.0%; cats: 43.2%) are considered relevant. Cats had significant (but unlikely relevant) fCal increases post-vaccination. Despite individual fCal spikes, no differences were seen during NSAID treatment. The fCAL turbidimetric assay is linear, precise, reproducible, and sufficiently accurate for measuring fCal in dogs and cats. Careful interpretation of fCal concentrations is warranted in both species during the peri-vaccination period and for some patients receiving NSAID treatment.

Synbiotic-IgY Therapy Modulates the Mucosal Microbiome and Inflammatory Indices in Dogs with Chronic Inflammatory Enteropathy: A Randomized, Double-Blind, Placebo-Controlled Study

“…Local (fecal calprotectin) and systemic (serum high sensitivity C-reactive protein [hs-CRP]) biomarkers of inflammation were evaluated in a subset of dogs at diagnosis (pre-treatment, visit 1, day 0) and after the treatment schedule was completed (post-treatment, visit 3, day 42). Fecal calprotectin was measured in samples from 12 dogs extracted to a final dilution of 1:500 (Calex Cap, Bühlmann Laboratories, Schönenbuch, BL, Switzerland) by a particle-enhanced turbidimetric immunoassay (fCAL turbo, Bühlmann) on a Cobas 311 chemistry analyzer (Roche Diagnostics GmbH, Mannheim, Germany) as described previously [ 36 ]. This assay has been validated for use with canine fecal samples and was shown to have a lower detection limit of 3 µg/g, a reference interval of 3−41 µg/g, and a minimum critical difference of 44.0% [ 36 ].…”

“…Fecal calprotectin was measured in samples from 12 dogs extracted to a final dilution of 1:500 (Calex Cap, Bühlmann Laboratories, Schönenbuch, BL, Switzerland) by a particle-enhanced turbidimetric immunoassay (fCAL turbo, Bühlmann) on a Cobas 311 chemistry analyzer (Roche Diagnostics GmbH, Mannheim, Germany) as described previously [ 36 ]. This assay has been validated for use with canine fecal samples and was shown to have a lower detection limit of 3 µg/g, a reference interval of 3−41 µg/g, and a minimum critical difference of 44.0% [ 36 ]. High-sensitivity C-reactive protein (hs-CRP) in serum was analyzed by sandwich ELISA according to the manufacturer’s instructions (MyBioSource Inc., San Diego, CA, USA).…”

Canine chronic enteropathy—Current state-of-the-art and emerging concepts

“…Careful selection of canine patients for fecal calprotectin testing is important to gain relevant information from this biomarker as increases also occur with acute gastrointestinal inflammatory conditions ( 183 ). Fecal calprotectin measurement in dogs is currently not routinely available, but a human immunoturbidimetric assay that can be run on standard laboratory chemistry analyzers has shown promise for fecal samples from dogs ( 182 , 184 ).…”

“…Several biomarkers evaluated over the last two decades appear clinically useful surrogate tools for guiding the management of dogs with CIE. Some functional biomarkers (e.g., serum cobalamin or fecal α 1 PI concentrations) are clinically routinely used in dogs with suspected CIE. Genomic biomarkers are currently not readily available but hold great promise for an individualized approach to risk assessment, treatment, and monitoring in canine CIE. Of the inflammatory biomarkers, only serum CRP is currently widely offered, but a human fecal calprotectin assay holds promise for use with specimens from dogs ( 182 , 184 ), increasing the diagnostic armamentarium in canine gastroenterology.…”

Chicken antibodies are highly suitable for particle enhanced turbidimetric assays

“…One of the most frequently used tests is fCal Turbo which is an IgY based PETIA ( 20 – 23 ). The assay has also been used for the detection of fecal calprotectin in dogs and cats ( 24 ).…”