Tampa, FL — The outcome of a sample analysis depends on a number of issues. This may include the technical competence of the laboratory staff, standard operating procedures, adequate quality assurance/control, and other good laboratory practices. Contaminant Control in Environmental Microbiological Laboratories – apart from these factors, the integrity of analytical results can also be influenced by the overall environmental conditions within a laboratory; this is referred to as “Laboratory Contamination” (LC). LC is defined as the inadvertent addition of contaminants to laboratory accepted samples during processing (e.g. storage, preparation, analysis, etc.).

Procedural and practical needs demand routine monitoring for contaminants in order to verify overall laboratory conditions and associated or potential risks to sample analysis. In the absence of uniform protocols, regulations that enforce LC monitoring are infrequent.

In the context of microbiological laboratories, a periodical laboratory monitoring is of high importance. As a matter of fact, conditions within a laboratory environment may persuade the integrity and validity of results. In recent years, awareness on this topic has gained importance both in the eyes of regulators and in the end users. This is crucial for laboratories dealing with microbiological investigations and it is essential to understand sources of contamination, and their effects, in order to address LC appropriately. Prospective routes of LC are:

  • External or extramural:

Elements introduced from sources other than the laboratory environment and have the potential to contaminate a laboratory are termed extramural.

  • Internal or intramural:

Internally generated elements that are capable of LC are referred to as intramural.

A periodical monitoring is a must for minimizing the potential risks associated with LC. Monitoring can be initiated in three phases:

  • Visual inspection

A walkthrough inspection/Visual Inspection is conducted to the entire laboratory facility. Any unusual, visible signs noticed during the inspection are documented. A sampling plan is formulated based on inspection and other relevant information (interview with occupants, complaint area vs. non-complaint area, etc.) to understand the source and extent of LC, if required or needed. The total number, types and sites from where samples need to be collected shall be determined at this stage by investigators.

  • Sample Processing:

A) Sample Collection:

Environmental samples/data from the air and surface are collected from selected test sites as determined by a thorough investigation in and around the laboratory environment. Samples may be collected as air, surface, liquid, gas, blanks, control, etc. Data such as temperature, relative humidity, concentration of carbon dioxide and any other desired/targeted elements are recorded during the time of sample collection for further analysis and their role as a contributor in LC.

B) Sample Analysis:

The collected samples are processed by utilizing non-culture techniques and/or culturable techniques as they are required for obtaining meaningful results. Non-culture Techniques for Environmental Material (NCTEM) includes microscopy, chromatography, mass spectroscopy, X-ray diffraction, electrophoresis, polymerase chain reaction (PCR), etc., whereas  Culture Techniques for Environmental Material (CTEM) are adapted to determine the extent of microbiological (bacterial, fungal or others) contamination in collected environmental samples. All other data, such as total airborne particulate counts, temperature, relative humidity, concentration of carbon dioxide, other target analytes or environmental data may also be collected by real time techniques during the period of investigation.

C) Interpretation of Data:

Results obtained during the investigation are analyzed statistically for a trend analysis. A positive correlation is indicative of LC. Data obtained during the evaluation can also illustrate a source-causation relationship, which helps in addressing the problem amicably. The historical review of periodical laboratory monitoring helps in developing acceptance criteria, which also assists in mitigating the potential effect of contamination on laboratory accepted samples. These trends may be obtained from, but are not limited to, remediation, running blanks, positive controls, negative controls and other types of quality controls. The entire process of laboratory monitoring is worthwhile to understand, not only to know what conditions your samples were analyzed, but also to authenticate the findings supplied to you as an end user.

D) Recommendations:

It is highly recommended to use laboratories which have a well defined protocol for laboratory monitoring for contamination control. The laboratory must be willing to share the findings of their periodical laboratory monitoring. In the event of nonconformity, how does a laboratory address such issues? These steps give extra credibility to the results of an end user. A recommendation can be made based on the information gathered from the visual inspection, environmental conditions and sample testing regarding the suitability of the laboratory environment.

For additional information you can contact Dr. Rajiv Sahay, Director, EDLab, Pure Air Control Services at 1-800-422-7873 ext 303.

About Pure Air Control Services, Inc.

Alan Wozniak founded Pure Air Control Services, Inc. in 1984 as a small mechanical contracting firm. Today, the firm sets the industry standard for indoor environmental quality diagnosis and remediation.

Pure Air’s nationally performed services include: Building Sciences Evaluation; Building Health Check; an Environmental Microbiology Laboratory; Environmental Project Management; and PURE-Steam Coil Cleaning/Mold Remediation Services, among other indoor environmental services.

The company’s expanding client roster includes the FAA, General Services Administration (GSA); Allstate Insurance; CBRE, Carrier Air Conditioning; NAVFAC, DOT, USACE, US Army, and many other Fortune 500 companies, school boards, and city, state, and county governments, making Pure Air Control Services the reliable industry leader.

For more information on Pure Air Control Services, Inc. please contact Jeff Nack or Alan Wozniak (800) 422-7873 ext 802 or 804 respectively, or explore this website.