Defining control reference ranges in biologic samples in analytical laboratories

Area of Science:

• Environmental Health Science
• Occupational Medicine
• Analytical Chemistry

Background:

• Mineral analytic laboratories establish control reference ranges to interpret individual exposure significance.
• These ranges are crucial for diagnosing asbestos-related diseases and assessing causation.
• Two scenarios exist: background controls (ambient asbestos exposure, no disease risk) and asbestosis range controls.

Purpose of the Study:

• To evaluate how different analytic laboratories establish internal control reference ranges.
• To comment on the significance of these internally defined ranges.

Main Methods:

• A review of scientific literature from a Pubmed search of mineral analytic data in lung tissue.
• Analysis of data from laboratories determining background exposures to asbestos and other elongate minerals.
• Inclusion of 26 publications from 17 laboratories across Europe, North America, and Asia.

Main Results:

• Marked heterogeneity was observed in control reference range establishment across laboratories and decades.
• Varied criteria, microscopic methodologies, and fiber dimension assessments were used.
• Chrysotile and amphiboles were frequently detected in lung tissue of control subjects, irrespective of disease status.

Conclusions:

• Significant interlaboratory variations exist, meaning results are not directly transferable between labs.
• The common criterion for background controls is no known occupational asbestos exposure or asbestos-related diseases.
• The study highlights the importance of negative control groups for validating asbestos exposure and disease results.