Sample Integrity Observation #13 Samples Received after Hold Time

Modified on: Thu, 20 Dec, 2018 at 8:58 AM


Purpose:  

Analyzing samples past the recommended hold time can compromise the integrity of the sample and the associated results.  In some cases, data may be inadmissible for reporting purposes.


Holding Time Information and Tips:

  • Review your projects for short holding time tests
  • Common short hold time tests include:•
    • Anions
    • Microbiology
    • Ferrous and Ferric Iron
    • Formaldehyde
    • Residual Chlorine
    • Turbidity
  • Review shipping options for quick delivery to the lab
  • Ship samples daily to the lab to allow as much time as possible for transit and analysis


Process:  The lab contacts you when samples are received past or very close to holding time for approval to proceed with any analysis.  In cases where a sampling time is not included on the COC, a sampling time of 4:00pm is assumed for the lab to proceed. 


Plan Your Shipping:

  • Remote sites are a challenge!  Sometimes, it’s just not logistically feasible to collect samples and have them arrive at the lab within holding time due to geographic shipping challenges.  Some field kits are available to test immediate hold time tests like pH and conductivity
  • Courier delays are an uncommon but unfortunate event that can’t be predicted or prevented.  Ship samples daily to the lab instead of ‘stockpiling’ samples.  Also try to avoid shipping samples with short holding time tests over holiday periods
  • When using one of the “large” courier companies, use electronic waybills wherever possible.  Service deliveries on manual waybills are not guaranteed and cannot always be immediately tracked in transit

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