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.