Immunoassay-based field analytical methods are rapidly gaining acceptance by the U.S. Environmental Protection Agency for use in site characterization and remediation. Many analysts, accustomed to using traditional laboratory methods, are reluctant to use immunochemical technology until they are convinced of its effectiveness. Therefore, it is important that experiences with using alternative technologies be shared with the analytical community. In this study, two immunoassaybased field test kits for polyaromatic hydrocarbons (PAHs) were evaluated. One was used in a quantitative format, the other in a semiquantitative format. Samples spiked with a commercial PAH mixture or creosote and field samples including soil and coal-derived liquids were analyzed. For the most effective use of the method, it is important to know the relative response factors (RRFs) for test ana-lytes relative to the kit standards. RRFs for creosote-spiked soil were about 2.3 and 0.11 for the quantitative and semiquantitative tests, respectively. This 20-fold difference in RRF between the two kits held for all the different samples tested and reflects the different antibodies and reference compounds used in the two tests. Potential problems with the integrity of the kit standards, which could significantly affect the interpretation of the test results, are discussed. Recovery of the PAH mixture and creosote from soil ranged from 75 to 90%. The specificity of a third test kit for carcinogenic PAHs was verified with the coal-derived liquids. Overall, both kits gave accurate and reproducible results and were judged to be effective tests for the analysis of PAH contaminated samples. แฎ