Interpretation Volume - Fasting volume is normally 50ml. If it is more than 250ml it suggests pyloric stenosis or hypersecretion of the gastric juice. Odour - Normal gastric juice has a faintly pungent odour. Foul and acid smell suggests pyloric stenosis. Offensive faecal odour suggests small intestinal obstruction or gastro-colic fistula.
Ammoniacal odour suggest achlorohydria.
Colour Blood red due to blood, confirmed by chemical test. It may due to - Trauma by the procedure or hemorrhage from Peptic ulcer, carcinoma of stomach or oesophageal . Coffee ground due to conversion of haemoglobin to acid hematin. Dark green colour due to bile, confirmed by chemical tests. It occurs due to regurgitation of the intestinal contents into the stomach.