Used Oil Analysis Results are Only as Good as the Quality of the Sample

Taking representative oil samples is the foundation of accurate (and useful) oil analysis results. The good news is that it’s not that hard as long as you follow a few simple guidelines laid out by Eurofins TestOil’s Matt McMahon, Oil Analyst III Field Technician.

                In order to correctly alarm out of range data on the report, consistent trend information needs to be established by sampling from a good location with a standardized procedure.

                “Accurate sampling makes a significant difference in test results; particularly when it comes to interpretation of the report as a whole.,” Matt says.  “There are two main considerations when taking a sample; sampling location and sampling technique. On our audits, we typically make recommendations of sampling locations and hardware. Often, if the sampling location is good, the reliance on lengthy and involved sampling procedures is lessened. Also, a good location precludes contamination being introduced into the machine during the sampling process.”

                Following are a few of Matt’s guidelines:

  • Sampling tools and supplies should be contamination free.
  • Consider the sampling location when creating sampling procedures. For example, drain samples will need to be flushed before capturing a sample.
  • Have set sampling procedures to eliminate variation due to different personnel taking samples.
  • Make sure to have machines clearly identified so that samples have the correct information. This problem happens frequently.  Eurofins TestOil sees issues with this on a daily basis.
  • Machines should be running while sampling. This means the sampling location should allow for safe extraction. If the machine needs to be turned off, the sample should be taken as soon after shutdown as possible.

                According to Matt, the lab analyst may or may not be able to tell if the sample was taken correctly. “Probably not if there is a lack of sampling history or very long sampling intervals,” he explains. “If the machine is regularly sampled at a reasonable interval (at the very least, quarterly), then we have a sense of sampling consistency by observing sample-to-sample variation. This applies to particle counts and water content in particular as these tests are sensitive to poor sampling technique. If there is a good deal of sample-to-sample variation, then it’s unlikely that we’re consistently getting a representative sample.”

                All this points to the third aspect of consistency—sampling at a consistent frequency.

                Most of Eurofins TestOil’s oil analysis classes include training on how to take an oil sample. “Having trained personnel, good sampling locations, set sampling procedures and clearly identified machines leads to confidence in making sound maintenance decisions,” Matt says.

                Eurofins TestOil also offers expert onsite sampling services.

                “Ultimately, a sample is only accurate if it is representative of the oil circulating in the machine,” Matt concludes.  “The important things to remember are consistent location, consistent procedure, consistent frequency.”

For more information on working with Eurofins TestOil for oil analysis and training visit Contact: 216-251-2510;

About Eurofins TestOil

With more than 30 years of experience in the oil analysis industry, Eurofins TestOil focuses exclusively on assisting industrial facilities with reducing maintenance costs and avoiding unexpected downtime through oil and fuel analysis program implementation. As industry experts in diagnosing oil-related issues in equipment such as turbines, hydraulics, gearboxes, pumps, compressors and diesel generators, Eurofins TestOil provides customers with same-day turnaround on routine oil analysis testing.  For more information on partnering with Eurofins TestOil on oil analysis programs or training opportunities visit Contact: Michael Barrett 216-251-2510; 

About Eurofins – the global leader in bio-analysis

Eurofins is Testing for Life. Eurofins is the global leader in food, environment, pharmaceutical and cosmetic product testing, and in discovery pharmacology, forensics, advanced material sciences and agroscience Contract Research services. Eurofins is also a market leader in certain testing and laboratory services for genomics, and in the support of clinical studies, as well as in BioPharma Contract Development and Manufacturing. The Group also has a rapidly developing presence in highly specialised and molecular clinical diagnostic testing and in-vitro diagnostic products.

With over 61,000 staff across a network of 940 laboratories in 59 countries, Eurofins’ companies offer a portfolio of over 200,000 analytical methods. Eurofins Shares are listed on Euronext Paris Stock Exchange.

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