Abstract: Background – The fecal occult blood test (FOBT) is important for diagnosing challenging anemias but voided fecal samples can be difficult to obtain. Sample collection method impact on FOBTs has not been assessed in veterinary medicine. In human medicine, fecal hemoglobin immunochemical tests (FITs) have largely replaced conventional FOBT methods due to their higher sensitivity and specifity. FITs have not been trialed in companion animals.
Hypothesis/Objectives – The primary objective was to determine if sample collection method (voided vs. digital rectal collection) affects FOBT results. The secondary objective was to assess human FITs’ capacity to detect canine and feline blood.
Animals – 308 privately owned dogs; healthy and sick.
Methods – Guaiac FOBTs were performed on paired voided and rectally-obtained fecal samples. Two FITs (Hemosure One Step and OC-Light S) were tested with serially diluted human, canine, and feline blood.
Results – Voided and rectally-obtained samples showed good FOBT positivity agreement (k=0.80), with 92.5% concordance and 13/308 dogs negative on void but positive on rectal. Multivariate analysis showed dogs with gastrointestinal disease (p=0.0003 rectal; p=0.0001 void) were more likely, and heavier dogs (p=0.0037 rectal; p=0.0022 void) less likely, to test positive. Health status, platelet count, fasting status, NSAID use, and age were associated with FOBT result on univariate, but not multivariate, analysis. FITs did not detect canine or feline blood.
Conclusions and clinical importance – Rectally-obtained fecal samples can be reliably used for FOBTs. Human FITs may not be suitable for companion animals, but evaluation of further tests is needed.
