Environment Testing >> Environmental Testing Blog >> Analysis and Data Interpretation

A Brief Overview of Your Analysis Report

Sidebar Image

We know navigating the process to have your local habitat analyzed — whether it's water, air, soil, sediment, or something else entirely! — can be daunting. If you've never worked with a laboratory before, you may not know what to expect. Fortunately, Eurofins Environment Testing is able to help you with any analytical project from start to finish.

Cover page

Example of report cover page. (Click to enlarge)

Perhaps the most anticipated part of the process is when you receive your results. With state-of-the art technology, instrumentation, and resources dedicated to environmental testing, our teams are able to shorten turn-around-times and deliver results in a timely fashion.

So you've got the report in your hands — what do you do now?

If you have a scientific background, interpreting the data is pretty straightforward. For the rest of us, it can be a lot of information to unpack. The information you will receive is packaged into two main parts: the report, and a quality control (QC) summary. We took a look at some reports from Eurofins Lancaster Laboratories Environmental and outlined their sections here:

  • Cover page – Shows all samples reported in the group
  • Analytical results – per sample, for each requested analyte
  • Laboratory Sample Analysis Record (LSAR) – per sample; documentation of the date, time, method, batch number, and analyst name
  • QC Summary – QC results per batch

The Report (Analytical results)

Analysis Report example

An example of the report featuring analytical results. (Click to enlarge) 

The report contains all the analytical results, AKA the numbers. It lists parameters, including detection limits. Analytes are listed on the left, and through the middle to right you see the Limit of Quantitation (LOQ) and Method Detection Limits (MDL).

The MDLs are determined through a study that statistically evaluates the preparation and analysis of seven replicates of a standard spike in the range of the expected MDL. This generates the calculated (or statistical) MDL. The reported MDL is derived from this study.

“As Received” MDL is the unadjusted MDL. The regular MDL has been adjusted or corrected by taking into account the moisture in the sample. (This applies to soil samples only, where the data is being reported on a “Dry Weight” Basis. Some clients and states will require “Dry Weight” adjusted results to compare data. By calculating the moisture in each sample and correcting the data and detection limits, the client or data end user is now able to compare the data without dealing with any kind of dilution variable.)

The LOQ is the level above which quantitative results may be obtained with a specified degree of confidence.

The data results are reported with either the corresponding MDL or the LOQ, and there are report formats that can show both. You can determine the specific format you need, based on action levels that you may need to evaluate.

It’s important to note that these figures don't constitute a black or white, yes or no answer. But the rest of the report helps you to read these numbers to understand what they mean.

The report will also include common qualifiers, which are indicated by different letters. You can find the definitions for these letters on the last page of the report, usually at the end of the QC summary. Some of the more common ones are listed below: (page 10 complex, data qs-reports, symbolsabbreviationsqualifiers)

  • J - Appears in bold, means that the estimated value is greater than or equal to the MDL and less than the LOQ
  • U - Analyte was not detected at the value indicated

   

An example of a report with many qualifiers, shown by the red outline.

Examples of common qualifiers.

Explanation of symbols and abbreviations in the analytical report; and more definitions of data qualifiers.

QC Summary

This section demonstrates the accuracy and precision of the methods chosen to analyze your samples. As previously stated, they don't signify a black-and-white answer, and they must be compared to specific regulatory limits (if applicable) to determine what you might have to do next. Outliers are flagged on summary with an asterisk. (*)

An example of the first page of the QC summary.

  1. Method Blanks (BLK)
  • A clean matrix that goes through the entire preparation and analysis process
  • Used to determine if any contamination was introduced during processing
  • One blank for each sample batch
  • Compliant when nothing detected above the applicable detection limit
  1. Laboratory Control Sample (LCS), Lab Control Sample Duplicates (LCSD)
  • A clean matrix fortified with a known concentration of target analytes (Not an actual field sample)
  • One LCS for each sample batch
  • Duplicates (LCSD) are used if there is insufficient sample volume for Matrix Spike Duplicate
  • Produces a percent recovery figure, compared to acceptance limits
  • “Outside of specifications” does not mean unusable
  1. Matrix Spike (MS), Matrix Spike Duplicate (MSD)
  • Two parts of the sample matrix are spiked with known concentration of target analytes
  • One MS/MSD pair for each sample batch (Depending on the method)
  • Produces a percent recovery figure, compared to acceptance limits
  1. Duplicates (DUP)
  • Secondary portion of a sample
  • One DUP for each preparation batch( Depending on the method)
  • Results compared and Relative percent difference (RPD) is determined
  • Assesses precision of processes
  1. Surrogates
  • Only used for Organic methods
  • Similar, non-target analyte added to each sample
  • Percent recovery compared to acceptance limits
  • Used to assess extraction efficiency and matrix effects

Qualified Data

Although the laboratory goes to great lengths to avoid qualified data, no laboratory data is perfect. The qualifications must be reviewed and understood so they can be evaluated against the project objectives. In many cases the data is still usable for its purpose despite the qualifications.

Finally

Each piece of the report issued is required by law, which can vary from state to state. Eurofins is in compliance with all of the state and federal regulations.  We do offer services like myEOL to simplify receiving and reading your results.

On www.myEOL.com, you can view extensive, live project information such as submitted samples, chains of custody, sample receipts, document logs, final reports and invoices. myEOL also allows you to compare your results to regulatory limits, show exceedances and export the data, making it easier for you to see the comparison between sample results, reporting limits and applicable regulatory limits.

Every number listed on your report helps to prove the accuracy of our methods and instrumentation. We never want to present clients with misleading data. In all, it may appear overwhelming at first, but the vast collection of data is like insurance for the validity of your results. We believe the more transparency, the better.

Lastly, we recognize that every client, each project, and each sample can vary, so some of the details we’ve featured here may not apply specifically to your testing needs. This guide is by no means comprehensive, so please be sure to contact your Client Service Representative if you have any questions.