A sample testing device has a buffer container that can hold buffer fluid, a filter with a securement for holding a test strip, the test strip, a test strip container having a receptacle to accommodate the filter, so that when the filter is held therein the test strip is disposed in the receptacle, and a sample collector for holding a sample. The sample collector receives the buffer container, and the sample collector has a piercing member which, when the buffer container is placed in the sample collector, pierces the buffer container. Buffer fluid in the buffer container then contacts the sample. As buffer fluid flows through the sample collector, the buffer fluid that has contacted the sample passes through the filter to the test strip.