MetriCide OPA Plus Solution Test Strips were developed to indicate when the minimum recommended concentration (MRC) of ortho-Phthalaldehyde (OPA) in MetriCide OPA Plus Solution has been reached during the reuse process. Use of a test strip is recommended before each reprocessing cycle to ensure health care professionals that the disinfectant has not been compromised by excessive reuse, contaminated due to inadequate equipment cleaning, AER malfunction causing excessive dilution or misuse of the product.