Evaluation of the guaiac fecal occult blood test for detection of gastrointestinal bleeding in the rhesus macaque (Macaca mulatta)

Gastrointestinal bleeding in children: diagnostic approach

Different conditions may underlie gastrointestinal bleeding (GIB) in children. The estimated prevalence of GIB in children is 6.4%, with spontaneous resolution in approximately 80% of cases. Nonetheless, the initial approach plays a pivotal role in determining the prognosis. The priority is the stabilization of hemodynamic status, followed by a systematic diagnostic approach. GIB can originate from either upper or lower gastrointestinal tract, leading to a broad differential diagnosis in infants and children. This includes benign and self-limiting disorders, alongside serious conditions necessitating immediate treatment. We performed a nonsystematic review of the literature, in order to describe the variety of conditions responsible for GIB in pediatric patients and to outline diagnostic pathways according to patients' age, suspected site of bleeding and type of bleeding which can help pediatricians in clinical practice. Diagnostic modalities may include esophagogastroduodenoscopy and colonoscopy, abdominal ultrasonography or computed tomography and, when necessary, magnetic resonance imaging. In this review, we critically assess these procedures, emphasizing their respective advantages and limitations concerning specific clinical scenarios.

In vitro Validation Assessment of a Fecal Occult Blood Protein Test for Horses

A commercially available equine fecal blood test (FBT) claims to be able to detect the presence of blood proteins (albumin and hemoglobin) in manure. The purpose of this study was to determine the FBT test sensitivity, specificity, positive and negative predictive values (PPV, NPV), lower threshold of detection, time to obtain a visual positive result, effect of temperature and result stability in lab and field conditions. The FBT was assessed for its sensitivity and specificity for detecting pure albumin and hemoglobin at two temperatures over a range of concentrations. Time to result was measured for up to 60 minutes. PPV and NPV were assessed by measuring albumin and hemoglobin in manure from 13 pleasure horses over 25 days. Laboratory tests of hemoglobin alone, albumin alone, and hemoglobin and albumin combined were tested over a range of concentrations from 0.0125 ppm to 50 ppm. In the field study, fresh (within 30 minutes) manure was sampled and tested for proteins using the FBT. The FBT was both sensitive and specific to hemoglobin and albumin. The effect of cold temperature on time to a positive result at 15 minutes was not significant. Results were stable for up to 60 minutes. The field study showed evidence that the appearance of blood proteins in manure was intermittent, and that three tests on consecutive days provided a much better PPV and NPV. It is concluded that this FBT had high specificity, sensitivity, PPV, NPV, was equally functional at low and moderate temperatures, provided a rapid (within 15 minutes) and stable (for up to 60 minutes) reading. Its use in the field is simple and effective.

Evaluation of the guaiac fecal occult blood test for detection of gastrointestinal bleeding in the rhesus macaque (Macaca mulatta)

BACKGROUND

Gastrointestinal (GI) hemorrhage accompanies several common diseases of rhesus macaques (Macaca mulatta). Guaiac fecal occult blood testing (gFOBT) is a non-invasive means to detect such bleeding in several species; however, there are currently no data indicating reliability of this test to detect GI hemorrhage in macaques.

METHODS

We evaluated sensitivity and specificity of gFOBT to detect simulated and biopsy-associated bleeding in the stomach, duodenum, and colon of 15 rhesus macaques. Fecal samples were analyzed via gFOBT for 72 hours.

RESULTS

Guaiac fecal occult blood testing was more sensitive to detect lower vs upper GI bleeding; sensitivity was volume-dependent in the upper GI tract. Single-test specificity was 95.2%. Repeated fecal collections increased gFOBT sensitivity without affecting specificity.

CONCLUSIONS

Guaiac fecal occult blood testing is a useful screening test for both upper and lower GI bleeding in rhesus macaques. For highest sensitivity, gFOBT should be performed on three fecal samples collected 24 hours apart.