What are reference slides and how are they obtained?
Reference slides are test slides with statistically derived reference values and limits of acceptability. To comply with the requirements of the NIOSH 7400 and OSHA ID-160 methods, at least one reference slide must be analyzed by each analyst prior to fiber counting any real-world or client samples. Industrial Hygiene Proficiency Analytical Testing Program (IHPAT) and/or Asbestos Analytical Testing (AAT) Program proficiency samples and statistically validated client or working samples representing all four fiber-loading ranges should be included in a well-developed reference library. IHPAT and AAT proficiency test samples have already been statistically evaluated by AIHA Registry Programs, LLC. Results typically include a reference value and limits of acceptability. To statistically validate a client sample test slide, a minimum of 10 readings by an experienced analyst(s) must be obtained. The mean value of these readings will then be considered the reference value for the test slide,
