Can Drones Deliver Lab Specimens?

Abstract
Objectives
We addressed the stability of biological samples in prolonged drone flights by obtaining paired chemistry and hematology samples from 21 adult volunteers in a single phlebotomy event—84 samples total.

Methods
Half of the samples were held stationary, while the other samples were flown for 3 hours (258 km) in a custom active cooling box mounted on the drone. After the flight, 19 chemistry and hematology tests were performed.

Results
Seventeen analytes had small or no bias, but glucose and potassium in flown samples showed an 8% and 6.2% bias, respectively. The flown samples (mean, 24.8°C) were a mean of 2.5°C cooler than the stationary samples (mean, 27.3°C) during transportation to the flight field as well as during the flight.

Conclusions
The changes in glucose and potassium are consistent with the magnitude and duration of the temperature difference between the flown and stationary samples. Long drone flights of biological samples are feasible but require stringent environmental controls to ensure consistent results.

Several recent reports demonstrate that biological samples can be transported by unmanned aerial vehicles (commonly referred to as drones) without affecting the laboratory results from the same samples.1-3 However, the broad applicability of those studies to potential real-life drone transportation was limited by distance and temperature. Briefly, the earlier reports of drone-transported biologics were performed in ambient temperatures that were around room temperature or cold and the maximal length of flight in those studies was 40 minutes (equivalent of 40 km) in a fixed-wing vehicle and 27 minutes (equivalent of 13-20 km) in a multirotor. While these times and distances were sufficient as proofs of concept, they are not long enough to address the needs of real-world drone networks.
To illustrate, let us consider a hypothetical drone network with four satellites and one central hub, where each satellite is 20 km from the hub. Such a network would either require several drones and complex logistics or a single drone flying a total distance of around 100 km. This hypothetical distance would increase with countervailing winds or increased distance from the hub. Thus, given the expected real-world demands on drone networks as well as the many regions and seasons that are characterized by high temperature, there is a need to examine long drone flights at relatively high temperatures. This report attempts to address these needs by presenting the results of a 3-hour, 258-km drone flight at 32°C ambient temperatures and low humidity (mean, 27.2%; range, 24.9%-28.8%).
In our earlier work on the impact of drone flights on chemistry clinical laboratory results, there were no specific measures to stabilize temperature or pressure because ambient conditions were not extreme. Our test flights were performed at 100 m, and changes in temperature and atmospheric pressure with altitude were small. In the current report, the flights were at high ambient temperatures, low humidity, and protracted. Consequently, we constructed a custom-built active cooling device that was designed to run using power from the onboard battery. In addition, as the engine in the current drone was gas powered, we reasoned that its vibration might be a significant environmental factor (https://vimeo.com/medicaldrones/long-distance). To mitigate these effects, we packed the primary Vacutainers individually in plastic mesh sleeves. The primary containers were sealed in two flexible biohazard bags (Ziploc) with absorbent material, placed inside the custom cooler, and transferred to a custom-built foam-lined carrier attached to the bottom of the fuselage. The purpose of our study was to examine the effects on samples during real-life drone flights that are greater than 3 hours in duration and in relatively high ambient temperatures.

Read the entire study here: https://academic.oup.com/ajcp/article/doi/10.1093/ajcp/aqx090/4104555/Drone-Transport-of-Chemistry-and-Hematology