by the National Institute for Occupational Safety and Health, NIOSH Manual of Analytical Methods (1994)
“ These methods are intended to promote accuracy, sensitivity, and specificity in industrial hygiene analyses. There will be situations where users of the NIOSH methods will need to modify them (e.g., to accommodate interfering compounds from the workplace, to take advantage of special capabilities of the laboratory, to make possible the analysis of a single sample for several contaminants) . When method modifications are made, quality control data showing the reliability of the modified method should be obtained. ”
