Immunoassay test kits are promising technologies for measuring analytes under field conditions. Frequently, these field-test kits report the analyte concentrations as falling in an interval between minimum and maximum values. Many project managers use field-test kits only for screening purposes when characterizing waste sites because the results are presented as semiquantitative intervals. However, field-test kits that report results as intervals can also be used to make project-related decisions in compliance with false-rejection and false-acceptance decision error rates established during a quantitative data quality objective process. Sampling and analysis plans can be developed that rely on field-test kits to meet certain data needs of site remediation projects.