Proposed classification of clinical laboratory methods.

A Task Force appointed by the College of American Pathologists studied the key elements that may affect a laboratory result, including the types of reagents, manufacturers of detection equipment, blanking procedures, calibrators, diluting and dispensing devices, and sample preparation. A field trial was conducted using cholesterol assay as the pilot study. Participants completed a lengthy questionnaire that requested information regarding the key elements used in the cholesterol assay. This report presents the preliminary findings of the field trial. Examples are shown to illustrate how obtaining additional information about how the laboratory test was performed led to identification of subtle differences in test results.