|Institution:||University of Helsinki|
|Keywords:||plastic glove test; sand enteropathy; sand colic; faecal sand sedimentation; horse; sand; hevossairaudet|
|Full text PDF:||http://hdl.handle.net/10138/154689|
Sand enteropathy is a common form of equine colic in Finland. Detection of sand in the faeces of a horse is a widely known diagnostic method for intestinal sand accumulations. The plastic glove test is a faecal sand sedimentation test recognized by many equine practitioners. However, the diagnostic accuracy of the test is unknown, which restricts the use of the test. The main objective of this licentiate thesis was to determine the diagnostic accuracy of the plastic glove test. The most reliable diagnostic method for intestinal sand accumulations is abdominal radiography, and therefore it was used as a gold standard method against which the plastic glove test was compared. The hypothesis was that there is a positive correlation between the results of the plastic glove test and abdominal radiography. The study was conducted by collecting a faecal sample and an abdominal radiograph from each participating horse. A total of 63 faecal samples were collected from 61 different horses. All the horses were patients at the Veterinary Teaching Hospital of the Helsinki University. The cranioventral abdomen of each horse was radiographed, and the length and height of the sand accumulations were recorded. The plastic glove test was performed by mixing faecal material (~200 grams) and water (1 litre) inside a rectal sleeve. The suspension was left to hang, and the amount of sand sediment in the fingertips was recorded after 30 minutes and 24 hours. Each fingertip of the glove was assessed separately on a 0-3 numerical scale and then added up to make a total score out of 15 for each horse. The results were compared in a 2 X 2 table and ROC analysis. According to this study, the sensitivity of the plastic glove test is 82,61% (95% confidence interval 68,58% to 92,18%) and the specificity is 71,43% (95% confidence interval 41,90% to 91,61%). The positive predictive value is 90,48%, while the negative predictive value is only 55,56%. In the ROC analysis the area under the curve (AUC) is 0,771 with a 95% confidence interval of 0,644 to 0,870. The plastic glove test is a moderately accurate diagnostic test. A positive test result is usually correct, but it does not inform the severity of the condition. It can be used as an indication for further examinations or treatment. A single negative test result should not be used to exclude the disease. The plastic glove test can be a helpful tool in the diagnosis of sand enteropathy in the horse, but should not be relied on as the sole method of diagnosis due to the poor specificity of the test. Since the reference population in this study was the patient material of the Equine Hospital, more reliable results could be obtained by using a more comprehensive and randomized representation of the entire Finnish horse population. It should also be noted that 29% of the horses had been treated with psyllium and/or magnesium sulphate prior to the testing.