Detection of Helicobacter pylori

A method for detecting the presence of Helicobacter pylori in the gastroenteral tract of a subject, the method comprising the steps of:

• a) obtaining a volume of gas from the lungs and/or stomach of the subject;
• b) dividing the said volume of gas into first and second substantially equal portions;
• c) causing or permitting the first said portion of gas to come into intimate contact with a first electronic or electrochemical ammonia sensor connected to means for measuring the electrical resistance of the said first sensor;
• d) causing or permitting the second said portion of gas to come into intimate contact with ammonia absorbing means and then into intimate contact with a second electronic or electrochemical ammonia sensor connected to means for measuring the electrical resistance of the said second sensor;
• e) measuring the resistance of the first and second sensors when in contact with the said portions of gas;
• f) comparing the said resistances of the sensors to produce a compared value;
• and
• g) producing a visible output signal to indicate a positive or negative diagnosis of Helicobacter pylori infection according to whether or not the compared value exceeds a predetermined threshold value.