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Policy on Deviating Samples

Changes to Policy on Deviating Samples for all Environmental Customers / Hawarden Laboratory.

Further to previous communications, SYNLAB continue to raise awareness with our Clients, that UKAS, our accreditation body is in the process of enforcing a policy on deviating samples “TPS 63 UKAS Policy on Deviating Samples”


The Policy states that the international standards ISO/IEC 17025 and ISO 15189 require testing, calibration and medical laboratories to have procedures in place to ensure that the integrity of samples they test or calibrate is maintained, and results are reported accurately, clearly, unambiguously and objectively and, where necessary, include comments upon the quality or adequacy of the primary sample which may have compromised the result.

Further information on the policy statement issued by UKAS can be found by clicking on the link below:

The Laboratory Committee of the European co-operation for Accreditation (EA LC) has identified that too many accredited laboratories were not sufficiently critical about the samples they receive. Large numbers of deviating samples were being accepted, analysed (or calibrated) and reports issued without any remark.

The EA LC concluded that this practice does not meet the requirements of ISO/IEC 17025 and it is not in the interest of the laboratories, their customers or other end-users of the result(s) to allow this practice to continue. Consequently, they have harmonised their interpretation of the aforementioned standards and directed EA signatory Accreditation Bodies, which includes UKAS, to strengthen their focus on the handling of deviating (or potentially deviating) samples during assessments of applicant/accredited laboratories.

Further information on EA LC can be found on their website

SYNLAB have introduced a number of best practices to reduce deviating samples which include:

Extending Holding Times The laboratory has conducted a number of in-house stability trials to extend holding times which have been approved by UKAS.  For example: 

  • pH on waters – 7 days holding time extended to 14 days
  • Nitrite preservation on waters has extended holding time from 2 days to 20 days
  • EPH on waters – 7 days holding time extended to 15 days

Weekend opening Opening on a Saturday and Sunday ensures that your samples are not left in a courier depot over a weekend. Samples received over the weekend begin their journey through the laboratory as they would on a normal weekday.

Requesting duplicate vials Duplicate vials taken when sampling for volatile analysis help us to reduce and minimise deviations due to any headspace, dilutions or re-work that may be required.

Therefore, SYNLAB’s main amendment to our current deviating sample policy is to move to sampled on date rather than sample receipt date which has been our practice for some time.  This will begin on the 1st December 2012.

As a result, SYNLAB has also introduced a number of other procedures to optimise sample throughput in the laboratory. These include:

  1. Early identification of samples that have arrived with a sampled on date of 48hrs or more before receipt. Our Customer Service Team will proactively contact the customer to discuss the analysis options.
  2. Planning management system - prioritisation of samples for extraction and prep based on holding time.
  3. On-line ordering using @mis


  • Save 1 day of your holding time
  • Samples go straight to prep lab
  • Get your samples to the front of the queue if you order with @mis


From 1st December 2012, samples analysed outside of holding time will still be accredited under ISO17025, but samples that are deviating due to holding time exceedance, will see a statement included in the final report as required by UKAS.

Please contact our Customer Service Team should you require any further help or information.

Telephone: 01244 528777