One unanswered question is how widespread the problem is. It is unclear how many outdoor courier lockboxes are currently in use in the United States or globally; however, experts agreed it was a common occurrence, with some of the largest laboratory service providers offering outdoor courier lockboxes to their clients.
“Courier lockboxes are everywhere. All you need to do is walk around your clinics that are at your hospitals or clinics located around your grocery store to find them,” Dr. Wiencek said. “Some hang on doors, while others can be found on the ground in direct sunlight on a hot summer day.”
What’s more, institutions may not realize how leaving samples outdoors for extended periods can affect results. “Care teams are commonly unaware that samples placed in these poorly designed lockboxes can experience extreme summer or winter temperatures that may lead to incorrect results,” Dr. Wiencek said. “Healthcare providers need to understand the hidden dangers courier lockboxes have on the quality of their patient’s test results.”
Amy L. Pyle-Eilola, PhD, clinical chemistry director at Nationwide Children’s Hospital in Columbus, Ohio, said a major strength of the study by Dr. Wiencek and colleagues “is just that it was done at all.”
“I appreciate the real-world nature of this study and that it provides a snapshot of what conditions are really like in a lockbox in the summer,” she said in an interview.
In the clinical lab, receiving samples that had been sitting in a courier lockbox “is not uncommon,” Dr. Pyle-Eilola said.
“When I have encountered these situations, I have struggled to decide if it is still appropriate to run the tests. I always look to the medical literature for assistance with these situations, but there has been a paucity of information available on the impact of lockbox storage,” she explained.
The study by Dr. Wiencek and colleagues “provides some much-needed evidence for what is acceptable for lockbox storage conditions,” she said.
Areas of future research
Rodney E. Rohde, PhD, university distinguished chair and professor of the Clinical Laboratory Science (CLS) Program at Texas State University in San Marcos, said in an interview that the study “does a nice job of looking at multiple analytes and controlling for several variables,” but the sample size is small and the results may be difficult to generalize.
Dr. Pyle-Eilola highlighted another limitation — “a common shortcoming of these kinds of studies” — in the use of healthy donors for patient samples, which narrows the range of assay results.
“It is possible that more significant variation in results may be observed in additional analytes if the samples had higher concentrations of those analytes,” she said. “Moreover, this is clinically relevant as the samples stored in such lockboxes are not always from healthy individuals and have abnormal concentrations of analytes.”
Mario Plebani, MD, professor of clinical biochemistry and clinical molecular biology and chief of the department of laboratory medicine at University Hospital of Padova in Padova, Italy, agreed with that assessment.
“[T]he risks for errors and patient safety are higher for values near to the upper or lower reference value, and in general for samples collected in patients with particular diseases and clinical conditions,” he said in an interview.
“This paper deserves a commenting editorial to better highlight the urgent need for further studies on the same issue and in general on the risk in the pre-pre-analytical phase, including sample storage and transportation,” he noted.
Another area of future research is studying patient samples exposed to hotter or colder temperatures in outdoor courier lockboxes outside the mid-Atlantic area. “Here in Texas, temperatures can reach extreme heat levels,” Dr. Rohde said, who added that use of outdoor lockboxes is “very common in my region.”
Dr. Wiencek disclosed he has been a consultant on this research topic for Roche Diagnostics and received an honorarium for speaking on the subject from the American Association for Clinical Chemistry and American Society of Clinical Pathology. The other authors have no relevant conflict of interest. Dr. Pyle-Eilola, Dr. Rohde, and Dr. Plebani have disclosed no relevant financial relationships.
A version of this article first appeared on Medscape.com.