Exposure to biological particles in air (bioaerosols) potentially causes serious health effects and therefore are of relevance for environmental and occupational health. Pyrogen active substances, like endotoxins, can cause unspecific immune responses and airway inflammation, which may subsequently lead to acute or chronic diseases. Consequences of the inhalation of pyrogens from the inhaled air are coughing, impairment of lung function, fever and flu like symptoms. A repeated or constant exposure of high concentrations can lead to acute or chronic diseases. To evaluate the risk on workplaces, concentrations are measured in occupational settings. The most common method for the detection of endotoxins is sampling on filters and subsequent analyses by LAL or rFC tests. Workplaces are investigated on a regular basis, but until now there is no or little quality management for the sampling, storage and analyses of endotoxin samples. Goal of the project ENDOTOX was to establish a base for the quality assurance of endotoxin detection in occupational settings.
A procedure was established to produce a high number of samples with the same amount of endotoxin containing durst in a controlled and reproducible manner. With these samples the influence of storage and transport on the samples was evaluated, and procedures for the execution of an interlaboratory test were established and tested. A standardized setting for the production of standardized and reproducible pyrogen containing samples was established, evaluated and documented. Each step in the establishment and evaluation of the system was done in replicates to ensure a flawless execution. Standard procedures were established to make the production of samples for further experiments straightforward. With these samples the influence of storage and transport was evaluated. The results show that the storage at room temperature is adequate as no significant loss could be observed. The storage of samples up to 14 days showed no obvious loss of detectable endotoxin. The comparison of endotoxin concentrations before and after transport showed clear differences, these are a combined result of transport and the analyses by another laboratory. To compare the analyses of different laboratories to each other, standardized samples and standard procedures for the execution of the interlaboratory test are necessary. These protocols were developed and tested in the before established system.
The results of the trial interlaboratory test showed the need of improvement in sample shipping and clarification of the instructions for participants. These improvements were added to the standard protocols. The results of the participants were mostly in the range of 50 to 200 % of the reference samples. Nine participants provided in total 11 results for each test concentration, as some labs used to analyses procedures. Three results were above 200 % of the reference and three were below 50 %. Differences between the results could be found between the participants but also between the used analyses procedures. The information gained with this research project, the standardized procedures and technical settings for the quality assurance are important for all areas of occupational health and security dealing with pyrogen material. Interlaboratory tests help to ensure the quality of the analyses of samples. The results for the storage and transport of samples can be included in current working instructions of the DGUV. Furthermore, the procedures established in the project set the bases for further evaluation and quality assurance of procedures of occupational health monitoring, for example the sampling and processing procedures for endotoxin samples. The risk assessment of workplaces, the evaluation of safety precautions and the adaptation of work stations are based on as accurate measurements as possible.
prevention, measuring methodsDescription, key words:
biological particles, bioaerosols, endtoxins, pyrogen substances