Nature Metrics

GCN Frequently Asked Questions

Read some of the questions we frequently get asked about our GCN services below.


NatureMetrics has an online ordering portal ( that enables you to easily place your orders, track their progress and view the results of all your projects. To set up an account, simply email to register and we will get you set up. If you’re an existing customer and have forgotten your login details just go to the portal and click ‘forgot password’.
Orders placed by midday will be eligible for next day delivery.
Once we have dispatched your kits we will send you an invoice, we have 30 day payment terms. If you have a PO, please add this to the appropriate field when placing your order.
We offer 3 different services for GCN testing: our standard service (10 working days), fast service (5 working days), and super fast service (2 working days). We begin to process the samples as soon as possible but, as we cannot control the delivery time, analysis officially begins the day after the samples are delivered to the lab.
Natural England states that you should use “ kit per pond up to an area of 1 hectare. Beyond this, use an additional kit per hectare.”
Natural England states that samples should be taken between 15th April and 30th June.
Collection of GCN kits is included in the service price and a member of our team will book the collection with TNT on the date you set when you placed your order. Once booked, a confirmation email from the courier with the label(s) will be sent to you to print and attach to the side of the box(es). Alternatively, you can send them through normal postal channels (dangerous goods restrictions) to NatureMetrics Ltd, CABI Site, Bakeham Lane, Egham, Surrey, TW20 9TY. Please bear in mind that we do not arrange collections for Fridays in order to avoid samples being held in a depot over the weekend in an uncontrolled temperature environment.
Prior to sampling, the kit can be kept at room temperature and has a shelf life of 3 months. Once the sample has been taken, the kit should be kept in cool conditions and away from direct sunlight before transit which should be as soon as possible after sampling. The preservative in the tubes stabilises the DNA, meaning it’s possible to detect eDNA in samples up to 2 months after sampling, but we do not advise leaving them this long!
Natural England guidelines state that GCN kits have a 3 month shelf life. Once the sample has been collected and placed in the box it may be kept in a fridge or at room temperature for up to a week before returning to NatureMetrics, although we advise you to return them as soon as possible.
This is not a problem at all, simply email Joe at with the kit ID, project and new date.
You can move an unused kit to another project, simply email Joe on with the kit ID and which projects you are moving from and to.
Following analysis, NatureMetrics will send you a report through the order portal that summarises the results and provides you with the relevant information on method and quality control.
Results can be inconclusive for several reasons. It may be that the samples contained sediment, either due to the nature of the water body or because the samples were taken from a sediment rich part of the collection bag. Sediment typically contains inhibitory chemicals (dead plant matter, soil, etc.) that inhibit the DNA test. When we get an inconclusive result we perform DNA dilutions following the standard Natural England protocol to try and resolve this issue, but sometimes this isn't enough to completely remove those inhibitors and therefore we cannot provide you with a conclusive GCN result.
eDNA is typically detectable for 2 days from when the animal leaves behind the biological material, but has been reported to last for up to 300 hours, there is not a definite answer for this yet. The degradation of the DNA is slowest when it is cold, dark, or when the DNA is bound to sediment.
Bleach is the most widely used decontaminant, but the strength of the bleach is key. The minimum effective concentration is 1.5% NaOCl and this should be soaked for 1 minute and then rinsed with water and finally wiped off with 70% ethanol to remove all traces of bleach.
NatureMetrics has strict policies and procedures in place to minimise any risk of contamination. Our staff undergo rigorous training prior to GCN season and we routinely run quality checks with every test to ensure the risk of contamination is minimised. Our samples are extracted at a separate site to where the PCR is carried out.
As the volume of water sampled is so small, we do not get enough eDNA to carry out further analyses such as vertebrate metabarcoding surveys. You would need to collect a 1-2 Litre sample using our filter kits. Email for more information.

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