Abstract: A test strip for sampling a bodily fluid may include multiple layers of a substrate material, an adhesive between at least some of the multiple layers, and a microfluidic channel formed between at least some of the multiple layers. The test strip may further include multiple electrodes on one of the multiple layers, positioned and partially exposed within the microfluidic channel, an additional material positioned at or near an entrance to the microfluidic channel, to selectively limit the flow of at least one of bubbles or debris into the microfluidic channel, and at least one exit port in at least one of the multiple layers to allow for release of pressure from the test strip. In some embodiments, the test strip is a saliva analysis test strip. In some embodiments, the test strip includes multiple exit ports to prevent blockage of sample flow.

Abstract: A method of assessing a bodily fluid sample on a test strip may involve applying a periodic signal with a first electrode located at a first location in a microfluidic channel of the test strip, monitoring the applied periodic signal with a second electrode located at a second location in the microfluidic channel, and using a third electrode located at a third location in the microfluidic channel as a reference electrode. The method may also include: collecting the bodily fluid sample in the microfluidic channel; continuing to apply the periodic signal, monitor the periodic signal and use the third electrode as a reference electrode while collecting the bodily fluid sample; and determining that the bodily fluid sample is sufficient for analyzing, based at least in part on the applied and monitored periodic signal.

Abstract: A method for using saliva to measure at least one substance or physiological parameter of a human or animal subject may involve inserting a first end of a sensor into a handheld saliva testing device. The method may also involve receiving saliva from the subject on a second end of the sensor, moving the saliva from the second end of the sensor to the first end, and processing the saliva with the handheld saliva testing device to provide initial saliva data related to the at least one substance or physiological parameter of the subject. In some embodiments, the sensor remains inserted in the handheld device while the subject deposits saliva on the opposite, free end of the sensor.

Abstract: An ion sensor includes a substrate, at least one ion selective electrode deposited on the substrate, and a reference electrode deposited on the substrate. The sensor may further include an insulating layer placed over the ion selective electrode and the reference electrode and having openings for the ion selective electrode and the reference electrode, a microfluidic layer placed over at least part of the insulating layer, and a cover layer placed over the microfluidic layer. The reference electrode includes reference electrode material deposited on the substrate and a combination of a polymer and a chloride-containing salt deposited on the reference electrode material.