Our office used to be right next door to a chiropractor's who drew blood samples from his patients. In the back of the building, facing west with nothing blocking the afternoon sun, was a cheap, white metal lock-box where his samples baked while waiting for the reference lab's courier until long after his business closed for the day. By the time they were picked up they couldn't possibly render accurate test results. 
     Approaching him about the invalid test results he was receiving was not likely to have an impact. Let's just say he was one of those professionals who deserved to have three more letters added to the string of credentials end of his name: CBT (Can't  Be Taught).

Right now in almost every city above the equator tens of thousands of blood samples, maybe more, are suffering the same fate. Lockboxes all over the world are acting like Kenner Easy-Bake Ovens, wreaking havoc on sample quality as they await courier pickup. You and I know it, but now studies are showing just how far from reliable test results are when obtained from uninsulated, unmonitored courier lock boxes exposed to temperature extremes. 

An article published in Clinical Laboratory News summarizes two studies of the internal temperatures of outdoor lock boxes and their impact on sample quality. Temperature changes inside the lockboxes monitored during one study conducted in the summer found temperatures skyrocketed up to 116.4 degrees Fahrenheit without ice packs (46.9 Celsius). Significant changes were observed within one hour of lock-box storage for AST, glucose, lactate dehydrogenase, and potassium, as reported in an article recently published in the American Journal of Clinical Pathology. 

Stunningly, there are no standards for outdoor lockboxes that house blood samples awaiting courier pickup. As a result, the quality of the test result is dependent upon the practitioner's understanding of temperature extremes on their patients' samples and the amount of money they're willing to spend to minimize the impact of outdoor storage. Many reputable laboratories use high quality lock boxes and monitor temperatures regularly. Unfortunately, there are currently no regulations that mandate environmental controls for samples in transit or awaiting courier pickup, only best practices. 

Courier lockboxes can be the weak link in sample logistics from vein to lab. Even when the sample is collected and processed with the greatest care and adherence to the prevailing standards, any quality retained by good technique evaporates in poorly constructed and unmonitored lockboxes left in the elements. It's the ole garbage-in-garbage-out scenario. Take a look at your outdoor sample storage boxes and assess their internal temperatures. Use cooling packs and insulated lock boxes if the internal temps exceed 72⁰F (22⁰C). If that's not possible, change sample logistics to eliminate storage in extreme temperatures. 

Why bother training your staff to be the best when the samples they draw with great expertise are set out to nuked in a Kenner Easy-Bake Oven?

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typographical error noted

I appreciate your article drawing attention to the practice of leaving lab specimens in lock boxes. Even indoor lock boxes can create inappropriate temperatures for blood storage. Please note the temperatures indicated at the end of the article: "720F (220C)". Your typist missed the need to superscript the 0's. :-) Thanks

Cloie Bridgeo, 07/20/2021 08:11:33

typographical error noted

Thank you, Cloie! The error has been corrected. Nice catch!

Dennis Ernst, 07/20/2021 08:18:19

No regulations?

There are standards with at least one accrediting agency that all temperature dependant supplies (which would include patient samples) must be monitored including ambient temperatures. So I'm not sure the blanket statement of "there are no standards" is accurate.

mkesme, 07/20/2021 11:05:05

No regulations?

The passage states there are no standards for lockboxes that hold blood samples for courier pickup, which is true. There may very well be an accrediting agency with temperature-monitoring requirements for samples, but the problem is physician offices that use lockboxes for blood samples aren't regulated by lab accrediting agencies.

Dennis Ernst, 07/20/2021 11:39:39