Perfect GCN eDNA proficiency test score for the fifth year running

Published: 22nd February 2022

At NatureMetrics we’re celebrating our fifth consecutive year of perfect scores in GCN proficiency testing, making us a partner of choice for anyone wanting to work with a high-quality experienced team. We were one of only seven companies who took part in the proficiency testing, a prerequisite for selling GCN eDNA tests in 2022, meaning NatureMetrics are gearing up to deliver another high capacity GCN season. The only difference this year is that we will be operating out of our brand new, high capacity, state-of-the-art laboratory at the Surrey Research Park, Guildford.

A high quality GCN experience with NatureMetrics

At NatureMetrics we offer an end-to-end service that promises high quality and ease of use. During GCN season, you can place and track your GCN orders online with your my.naturemetrics account. Orders placed before 12 pm will be delivered to you the next working day. We offer full logistics support and have a 2, 5 and 10 day turnaround services to suit the needs of your project.  Our NatureMetrics sampling app allows your field team to conveniently and rapidly collect your data in the field.

GCN proficiency test results explained

Each year a blind proficiency test is performed. Ten samples (labelled A – J), which comprise simulated pond water including a mixture of blanks and GCN eDNA spiked samples, are sent to each of the participating eDNA labs using each company’s own GCN eDNA kits. The labs then process and analyse the samples following the protocol set out in the WC1067 Appendix 5 Technical Advice Note, as routinely as they would during the sampling analysis season (15th of April – 30th of June).

The labs then submit the status of each of those samples. This year the samples comprised:

  • 4 positive GCN samples (D, E, H, I)
    • 3 low level GCN samples (D, E, H)
    • 1 medium level GCN sample (I)
  • 4 negative samples (A, C, F, G)
  • 2 inhibited samples (B, J)
Sample A B C D E F G H I J
Result Neg. Inh. Neg. Pos. Pos. Neg. Neg. Pos. Pos. Inh.
Score 0 0* 0 5 5 0 0 4 11 0*

Of the seven companies that took part this year – 6 of the 7 were able to score a perfect 100%, highlighting the positive impact of these tests and the general coming of age of the technology and methodology.

What do these results mean?

Taking a closer look at what each result means can help our customers to understand more about what to expect from their GCN eDNA results. We use PCR reagents that bind specifically to GCN DNA and amplify exponentially – this signal is possible to measure by fluorescence.

  • GCN eDNA presence indicates that GCN eDNA has been detected using our qPCR workflow (fluorescence detected). We go above and beyond to provide robust GCN data and can confidently report positive GCN eDNA results using our workflows.
  • GCN eDNA absence indicates that there is a lack of GCN eDNA in your sample (no fluorescence detected), and we can confidently report this as supported by our 100% proficiency results in the blind test, where we correctly identified all negative samples.
  • Inhibited or inconclusive samples – Results can be inconclusive for two reasons – the eDNA is degraded or the sample is inhibited. The risk of degradation is limited by the ethanol in the kits, which are very robust when they are correctly stored and quickly returned to the lab. Inhibition is typically caused by chemicals present in the samples that inhibit the functioning of the test (e.g. dead plant matter, soil, etc.). When we detect inhibition, we perform DNA dilutions following the standard Natural England protocol to try and resolve this issue, but sometimes this is not enough to completely remove those inhibitors and therefore we cannot provide you with a conclusive GCN result. To find out more about how to take a high-quality sample, without issues of inhibition, tune into our ‘how to’ webinar on GCN eDNA!

For accounts, ordering & price enquiries, including applying bulk discounts to your orders, please contact our team at

To learn more about how eDNA can help you survey biodiversity well beyond GCN contact us on

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