A diagnostic test kit for detecting an analyte residing in a test sample is provided. The kit employs a lateral flow device that contains a membrane. A metering channel is formed in the membrane that is capable of delivering a controlled volume of the test sample to a detection zone upon initiation of the assay. Such a metering channel is particularly effective for embodiments in which the test sample has a relatively low volume, such as less than about 100 microliters, in some embodiments from about 0.5 to about 25 microliters, and in some embodiments, from about 1 to about 10 microliters. For example, whole blood drops obtained from patients with a lancet typically have a volume of less than about 3 microliters. Despite their low volume, the present inventors have discovered that the blood drops may still be accurately analyzed for the presence of an analyte using lateral flow detection techniques.