BACKGROUND : Equine gastric ulcer syndrome (EGUS) is common in adult horses, particularly those involved in performance
disciplines. Currently, detection of EGUS by gastroscopy is the only reliable ante mortem method for definitive
diagnosis; however it is unsuitable as a screening test because it is expensive, time consuming, and is not readily available
to most veterinarians. Sucrose permeability testing represents a simple, economical alternative to gastroscopy
for screening purposes, and the feasibility of this approach in the horse has been previously reported. The aim of this
study was to determine the diagnostic accuracy of blood sucrose as a screening test for EGUS in a large group of adult
horses with and without naturally occurring gastric disease.
RESULTS : One hundred and one adult horses with or without naturally occurring gastric ulceration were studied. The
diagnostic accuracy of blood sucrose for diagnosis of gastric lesions (GL), glandular lesions (GDL), squamous lesions
(SQL), and clinically significant lesions (CSL) at 45 and 90 min after administration of 1 g/kg of sucrose via nasogastric
intubation was assessed using receiver operator characteristics (ROC) curves and calculating the area under the curve
(AUC). For each lesion type, sucrose concentration in blood was compared to gastroscopy, as the gold standard, and
sensitivities (Se) and specificities (Sp) were calculated across a range of sucrose concentrations. Ulcer grading was
performed blindly by one observer; and the results were validated by comparing them with that of two other observers,
and calculating the level of agreement. Cut-off values were selected manually to optimize Se. The prevalence of
GL, GDL, SQL, and CSL was 83, 70, 53 and 58% respectively. At the selected cut-offs, Se ranged from 51 to 79% and Sp
ranged from 43 to 72%, depending upon the lesion type and time of sampling.
CONCLUSIONS : Blood sucrose is neither a sensitive or specific test for detecting EGUS in this population of adult horses
with naturally occurring gastric ulceration. Further studies aimed at evaluating the performance characteristics of the
test in different study populations are warranted. Given the limitations of endoscopy, due consideration should also
be given to alternative methods for comparison of blood sucrose with a gold standard.