Can Unmanned Aerial Systems (Drones) Be Used for the Routine Transport of Chemistry, Hematology, and Coagulation Laboratory Specimens?

<div><p>Background</p><p>Unmanned Aerial Systems (UAS or drones) could potentially be used for the routine transport of small goods such as diagnostic clinical laboratory specimens. To the best of our knowledge, there is no published study of the impact of UAS transportation on laboratory tests.</p><p>Methods</p><p>Three paired samples were obtained from each one of 56 adult volunteers in a single phlebotomy event (336 samples total): two tubes each for chemistry, hematology, and coagulation testing respectively. 168 samples were driven to the flight field and held stationary. The other 168 samples were flown in the UAS for a range of times, from 6 to 38 minutes. After the flight, 33 of the most common chemistry, hematology, and coagulation tests were performed. Statistical methods as well as performance criteria from four distinct clinical, academic, and regulatory bodies were used to evaluate the results.</p><p>Results</p><p>Results from flown and stationary sample pairs were similar for all 33 analytes. Bias and intercepts were <10% and <13% respectively for all analytes. Bland-Altman comparisons showed a mean difference of 3.2% for Glucose and <1% for other analytes. Only bicarbonate did not meet the strictest (Royal College of Pathologists of Australasia Quality Assurance Program) performance criteria. This was due to poor precision rather than bias. There were no systematic differences between laboratory-derived (analytic) CV’s and the CV’s of our flown versus terrestrial sample pairs however CV’s from the sample pairs tended to be slightly higher than analytic CV’s. The overall concordance, based on clinical stratification (normal versus abnormal), was 97%. Length of flight had no impact on the results.</p><p>Conclusions</p><p>Transportation of laboratory specimens via small UASs does not affect the accuracy of routine chemistry, hematology, and coagulation tests results from selfsame samples. However it results in slightly poorer precision for some analytes.</p></div

Bland Altman plots showing absolute differences in results for 56 flown versus stationary sample pairs.

<p>The dashed lines delineate the 95% limits of agreement. The blue lines show the mean difference for analytes where this was > 0.2% of the mean values for each analyte. 1, WBC. 2, RBC. 3, Hb. 4, Hct. 5, MCV. 6, MCH.7, MCHC. 8, RDW. 9, Platelet count. 10, MPV. 11, Lymphocytes. 12, Monocytes. 13, Neutrophils. 14, Eosinophils.</p

Hematology results from flown and stationary samples.

<p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0134020#pone.0134020.t002" target="_blank">Table 2</a>. Summary of the hematology results from flown and stationary samples; as well as analytic CV’s based on controls versus sample pairs.</p><p>*These are population CV’s.</p><p>Hematology results from flown and stationary samples.</p

Hematology results from flown and stationary samples.

<p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0134020#pone.0134020.t002" target="_blank">Table 2</a>. Summary of the hematology results from flown and stationary samples; as well as analytic CV’s based on controls versus sample pairs.</p><p>*These are population CV’s.</p><p>Hematology results from flown and stationary samples.</p

Figure showing the packing of the sample payload.

<p>1. Custom-cut foam block. 2. Placement of sealed foam lock in the bio-hazard bags as well as absorbent material for potential sample containment. 3. Placement of first bio-hazard bag inside the second bio-hazard bag. 4. Placement of double-wrapped payload in the fuselage. 5. Covered, secured, and labeled fuselage. 6. Launch with hand toss.</p

Figure showing the packing of the sample payload.

<p>1. Custom-cut foam block. 2. Placement of sealed foam lock in the bio-hazard bags as well as absorbent material for potential sample containment. 3. Placement of first bio-hazard bag inside the second bio-hazard bag. 4. Placement of double-wrapped payload in the fuselage. 5. Covered, secured, and labeled fuselage. 6. Launch with hand toss.</p

Schematic of the experiment.

<p>Schematic of the experiment.</p

Bland Altman plots showing absolute differences in results for 56 flown versus stationary sample pairs.

<p>The dashed lines delineate the 95% limits of agreement. The blue lines show the mean difference for analytes where this was > 0.2% of the mean values for each analyte. 1, WBC. 2, RBC. 3, Hb. 4, Hct. 5, MCV. 6, MCH.7, MCHC. 8, RDW. 9, Platelet count. 10, MPV. 11, Lymphocytes. 12, Monocytes. 13, Neutrophils. 14, Eosinophils.</p

Bland Altman plots showing absolute differences in results for 56 flown versus stationary sample pairs.

<p>The dashed lines delineate the 95% limits of agreement. The blue lines show the mean difference for analytes where this was > 0.2% of the mean values for each analyte. 1, Sodium. 2, Potassium. 3, Chloride. 4, Carbon Dioxide. 5, Urea Nitrogen. 6, Creatinine. 7, Glucose. 8, Calcium. 9, Anion Gap. 10, SUN/Cr. 11, PT. 12, INR. 13, aPTT. 14, aPTT ratio.</p

Coagulation results from flown and stationary samples.

<p><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0134020#pone.0134020.t003" target="_blank">Table 3</a>. Summary of the coagulation results from flown and stationary samples; as well as analytic CV’s based on versus sample pairs.</p><p>*These are population CV’s.</p><p>**Simple linear regression</p><p>Coagulation results from flown and stationary samples.</p