Colorimetric detectors indicate the presence of a target chemical through a chemical reaction that results in a color change. Colorimetric test kits are available for a wide variety of CBRNE targets and includes M8 paper for CWA detection to the SPX 300 for trace explosives detection.  The tests are usually analyte and/or class specific and are well suited for presumptive testing of compounds with suspected identity.  Results are typically examined by comparison of the resulting color to a key in the test kit.  However, a few vendors offer electronic readers that provide more objective results than visual comparison and can store the results of a test.  Detection limits are typically in the part-per-million to part-per-thousand range (ppm-ppth), depending on the analyte.

Typically colorimetric detection has a small form factor and can be easily transported by hand.  As the tests are based on chemical reactions, they generally require little or no additional power to conduct.  There are a large number of colorimetric test kits available.  Kit cost varies depending on the analyte and the number of reagent packets in the kit.  They typically require one-time use consumables such as cartridges, reagents, papers or swabs for each target chemical.