Abstract: The present invention relates to the field of methods and apparatus for the determination of various conditions of gastric and gastro-intestinal malfunction, especially those performed by means of breath tests.

Abstract: An NDIR spectrometer based on the use of wavelength specific lamp sources, whose emission spectrum consists of discrete, narrow lines characteristic of the isotope present in the lamp, and which it is desired to measure with the spectrometer. This allows very high intrinsic sensitivity, enabling the use of an extremely compact absorption cell with a very short path length. In addition, the source can be self-modulated, such that problems associated with external choppers are avoided. Furthermore, there is insignificant cross sensitivity between the isotopes themselves and between the isotopes and other ambient gases in the operating environment.

Abstract: A calibration checking device, and methods of mandating its use at regular time intervals, to ensure maintenance of the accuracy of gas analyzers, especially for use with breath tests. Each calibration checking device is designed to be used for a predetermined number of tests. After first connection of a new calibration checking device, a volume of known calibration checking gas is released into the instrument, and a calibration checking measurement is initiated. A signal is sent to a counting mechanism which both enables the use of the instrument, and commences a count of the number of tests performed by the breath tester. When the number of tests is exceeded, the instrument is disenabled. The device can include a moisture filter having an interface with the instrument, which prevents its operation if the filter is used beyond the recommended number of times, or if excess moisture renders it saturated.

Abstract: A calibration checking device, and methods of mandating its use at regular time intervals, to ensure maintenance of the accuracy of gas analyzers, especially for use with breath tests, Each calibration checking device is designed to be used for a predetermined number of tests. After first connection of a new calibration checking device, a volume of known calibration checking gas is released into the instrument, and a calibration checking measurement is initiated. A signal is sent to a counting mechanism which both enables the use of the instrument, and commences a count of the number of tests performed by the breath tester. When the number of tests is exceeded, the instrument is disenabled. The device can include a moisture filter having an interface with the instrument, which prevents its operation if the filter is used beyond the recommended number of times, or if excess moisture renders it saturated.

Abstract: An automatic breath collecting and sampling system, which is preferably carried by the subject, or otherwise kept with him or near him, for the recommended duration of the collection period. The system collects samples in separate switchable containers, either at predetermined time intervals, or in response to an automatic stimulus, which could be related to the breath content itself, or to another physiological signal, such as the subject s pulse rate, breath rate, blood pressure, or temperature, or in response to a signal related to an environmental effect, such as the presence of a strong concentration in the air of a foreign gas, which could be detected by an electrochemical sensor, or manually by the subject after being prompted by the system. After collection of the requisite number of separate containers, they may be detached and sent for analysis or other treatment.

Abstract: Methods of determining gastro-intestinal conditions by performing a succession of breath tests or others tests, particularly for determining the gastric emptying or gastric accomodation condition of a subject. Methods of performing successive gastric emptying tests with different test meals are also presented, enabling the gastric accommodation to be determined. The effects of different test means on the results is presented. Novel substrates for use in such tests are suggested, including the use of micro-encapsulation. Breath tests for the detection of bacterial overgrowth, lactose intolerance and combinations thereof are presented.

Abstract: Breath test methods and apparatus for increasing accuracy and reducing the time taken to achieve diagnostically useful results. In order to determine when an increase in isotopic ratio of the exhaled breath is clinically significant, methods are described for the use of a variable and multiple threshold level; for reducing the time taken to determine an accurate baseline level; and for avoiding the effects of oral activity when making measurements. To increase measurement accuracy, methods are described, using the results of the breath tests themselves, of continuous and automatic self-calibration to correct for drifts in the gas spectrometer absorption curves. A method for increasing the spectral stability of cold cathode discharge infra-red light sources for use in breath test instrumentation is described. Calibration checking devices and methods of mandating their use at regular time intervals are described, to ensure maintenance of the accuracy of breath tests.