As cochairman of the Helsinki workshops in 1997 and 2000, he helped formulate the Helsinki Criteria
for diagnosis and attribution of lung and pleural diseases to asbestos exposure.
The electron microscopic evaluation is only done if no or remarkably few asbestos bodies are found under the light microscope, but secondary lung changes like fibrosis, inflammation, putrefaction or autolysis are present, according to the current Helsinki Criteria .
Asbestos, asbestosis, and cancer, the Helsinki criteria for diagnosis and attribution 2014: Recommendations.
[16.] Asbestos, asbestosis and cancer: The Helsinki criteria for diagnosis and attribution.
Asbestos, asbestosis, and cancer: The Helsinki criteria
for diagnosis and attribution.
Asbestos, asbestosis and cancer: the Helsinki criteria
for diagnosis and attribution: a consensus report of an international expert group.
According to the Helsinki Criteria
[5,6], the Asbestosis Committee of the College of American Pathologists and Pulmonary Pathology Society  and the definition of the German Society of Pathology  the histological diagnosis of asbestosis requires both the diagnosis of fibrosis and the detection of incorporated asbestos bodies.
(3,4) The 1997 Helsinki criteria incorporated these findings into more evidence-based criteria for the diagnosis of asbestosis, requiring (1) diffuse interstitial fibrosis and (2) 2 or more asbestos bodies within a section area of 1 [cm.sup.2] or a count of uncoated asbestos fibers that falls into the range recorded by the same laboratory for asbestosis.
We conclude that strict histologic criteria such as the Helsinki criteria are useful for the positive identification of asbestosis among cases of advanced pulmonary fibrosis.
The "Helsinki Criteria" were put forward as "state-of-the-art" criteria for the diagnosis and attribution of certain lung and pleural disorders to asbestos exposure by a group which convened in Helsinki in 1997, and were further updated in 2004.
The Helsinki Criteria state that the risk of developing lung cancer is materially increased (by a factor of 2), even without asbestosis, under the following conditions: