A sample collector and test device is disclosed. The sample collector and test device may be used together as a diagnostic tool for collecting and assay of analytes contained in a sample. A sample collector is also disclosed which may be used with existing sample containers and or test devices. The sample collector may indicate sample adequacy when a sufficient volume of sample has been collected for assay and may also include a sample retaining feature which retains a portion of expressed sample for confirmatory testing, if desirable. The sample collector may also include a mechanism for expressing sample in a sample collector and/or test device. A test device is also disclosed for retaining and assay of an expressed sample. The disclosed test device may be used with existing sample collectors. In a preferred embodiment, test device is used with a preferred sample collector. Test device may include a locking feature for locking a sample retained on a sample collector or test device may be used to receive expressed sample collected from a syringe or another suitable sample delivery device.