Central Laboratory News for Investigator Sites eNewsletter • Issue 9 • 2013
Logistics Corner
In This Issue

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Do not send the following items back to Covance CLS with your samples:
-New or used needles
-Needle holders or pipettes
-Used draw tubes
-Unused tubes or vials
Please discard these items at your site to prevent staff injury or confusion upon receipt at Covance CLS.


KimIntroducing Kim, from our Site Communications Team based in Indianapolis. Kim was chosen as our spotlight for this Issue due to the dedication she displays each and every day in providing the best customer service possible to our investigator sites.

You might have had the opportunity to speak to Kim in the past, as she spent the first 10 of her 15 years at Covance CLS in our Investigator Support Services Call Center. 
[more about Kim]


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Preparation of Frozen Samples for Shipments to Covance CLS


The practice of flash-freezing biological specimen as a first intention way of freezing does not appear to be well documented in the scientific literature. The terms flash-freezing; or “snap-freezing” usually refer to anatomic pathology and tissue processing for frozen section, as the best way to insure the smallest ice crystal size and will result in minimal damage to the tissue. Liquid nitrogen, with a freezing temperature of -196°C, is highly recommended for freezing tissue, but other low temperature refrigerants can also be employed. We found no reference that provides specific instructions for “flash-freezing” standard blood or urine specimens, including a search through Clinical and Laboratory Standards Institute (CLSI) specimen-management guidelines and standards

frozen tubes in box

Standard Freezing
In its collection instructions to investigator sites, Covance CLS sometimes requires frozen shipment of specimens. This implies that during the sample preparation after collection, the sample should be placed to freeze immediately. For freezing specimens and keeping specimens stored in optimal conditions until shipment to a central laboratory, Covance CLS advises investigator sites engaging in a clinical trial to get equipped with at least one -70°C (or -20°C) freezer of scientific standard. The freezer should not be “frost-free” in order to avoid exposure of specimens to temperature cycles.

Dry ice Freezing
In those circumstances where the investigator site has no access to freezers or in contingency situations (i.e. freezer/power failure), the use of dry ice is an acceptable alternative for freezing biological specimens. Placing the specimen inside the dry ice (which temperature is close to -70°C) fulfills the same requirements as placing the specimen inside a -70°C freezer. In both cases, the specimen is suddenly placed in a very cold environment and freezes within minutes. Dry ice-freezing, however is not strictly speaking “flash-freezing”. Note that Covance CLS has performed no comparison study between dry-ice freezing and usage of standard freezers. We think reasonable to assume that both techniques have about the same “freezing power” on biological specimens and that the specimen stability is preserved (of course, as long as the cold environment is maintained).

We caution sites against relying only on dry-ice for freezing their specimens. Since most sites do not readily have access to dry ice, it must be ordered in advance. Besides, dry ice sublimates into carbon dioxide gas and requires site personnel to regularly replenish dry ice coolers, which may prove expensive on a long term. For those reasons we advise sites engaging in clinical trial to get equipped with freezers.

For samples that have been collected immediately prior to shipping pick-up and must be shipped frozen on the day of collection, it is also acceptable to place the samples directly in the dry ice of the shipment box. The caveat of freezing samples this way is the risk of seeing accumulation of frozen material near the specimen container stopper that may subsequently leak. Therefore placing samples in an upright position in a temperature controlled freezer is still the preferred and recommended method.