Stability of Biochemical Components in BloodSamples Transported by Tempus600/SysmexGLP Robot Reception System
Ida Boegh Andersen,1* Nina Mogensen,1 and Ivan Brandslund1,2
Background: TheDepartmentofClinical ImmunologyandBiochemistry, LillebaeltHospital,Denmark, andTIMEDICO inventedanddevelopedtheTempus600®,apneumatic tubesystem(PTS). This systemisonly2.5cm in diameter and sends blood tubes directly, without packing before transport. Request forms need notbeenclosed, sincesamplesare labeledwithpatientandbarcode ID.At theendof thepipes, a robot receivesand places the tubes onto aGLP transport systemafter the principle of “first in, first out” (FIFO), whereafterthe tubes are delivered to centrifuges and analytical equipment. Thewhole systemhas decreased the totalturnaround time (ToTAT) from2 to3h to<60min. Theaimof the studywas to validate theTempus600/GLProbot system for the 89most frequent or critical components.Methods: Two sets of blood samples were drawn from 100 patients. One set was sent by the Tem-pus600/GLP robot system, and the other was couriered directly to the laboratory for analysis. Resultswere compared using difference plots.Results: The results for 85 of the components did not deviate from the optimized fast courier referencetransport more than could be expected by the analytical variation. O2 saturation, oxyhemoglobin, and partialpressure of oxygen (PO2) deviated considerably froma clinical point of view. Partial pressure of carbon dioxide(PCO2) resultswere clinically acceptable for assessing patientswith obstructive lung disease for hypercapnia.Conclusions: The Tempus600/GLP robot system can be used for transport of themajority of routinelyused analytical tests.
IMPACT STATEMENTThe report describes the preanalytical impact of a new flexible pressurized tube transport
system for immediate dispatch of labeled blood tubes combined with a continuous flow receptionrobot amenable to subsequent automated chemistry and hematology analyses. We investigatedthe stability of 89 frequentlymeasured and critical analyses needed for the patient care in a generalhospital setting. The system allows for a broad range of cellular and chemical testing and reducesToTAT from 2–3 h to <60 min in our clinical and laboratory setting.
In 2006, we conceived a system to transport sin-gle blood tube samples in a dedicated pressurizedtube system with a diameter of only 2.5 cm to re-duce transportation time from new emergencyand trauma center reception areas in Danish hos-pitals. This scenario was based on statistics thatshowed that the transport time from sampling toreception in the laboratory was as long as 3 hours,an unacceptable timeframe given expectations byclinicians for receiving laboratory results on acutepatients within 1 h. (Supplemental Fig. A shows aloading robot system for tube transport as seen inthe wards. See the Data Supplement that accom-panies the online version of this article at http://www.jalm.org/content/vol1/issue4.) A local Danishcompany Fagtek, with experience in pressurizedtransport of fluids, was chosen to be a partner fordevelopment of the system, and from 2008 to2009, the first system was developed and con-structed for testing at the Lillebaelt Hospital. Thefirst results concerning impact on the analytical re-sults and differences, as compared to a couriertransport system, were published in by Hastrupet al. (1). Since 2009, the system has been installedin 15 Danish and 5 international hospitals withmore than 115 installations total.Previously, blood samples had been trans-
ported in vacuum tube systems in large contain-ers. This type of systemhas disadvantages of beingexpensive to acquire, install, and maintain and isalso difficult to accommodate in existing buildings.Furthermore, samples need to be packed and pro-tected by foam sheets during transport, and re-quest forms are often sent together with thesamples. In the mid-1990s, however, Danish hos-pitals were changing fromusing paper request sys-tems to using electronic requests; this allowedsamples to be labeled with the patient ID andsample-specific bar coding before sample trans-port. This system has made the paper request
forms obsolete, and thus the samples can betransported, as they contain all necessary informa-tion within the barcode label.The test system has been operational since
2009–2010 and demonstrated that it was possibleto install the pressurized tube system in an existingbuilding at low cost, similar to electrical wiring. Un-til now, the largest distance of transportation usingthe system has been 300–400m spanning up to 4floors in height. However, currently, a system isbeing built with a total distance of 1.6 km, enablingclosure of a neighboring hospital laboratory. Todate, there has not been a blood tube that hasbrokenwith the systemor leaked during transport.As a precaution, if contamination occurs, the sys-tem is designed for easy cleaning using cylinder-shaped sponges.In the test system, the tubes were received in a
batch sorter. When designing the new system atthe Lillebaelt Hospital that included highly roboticanalytical procedures and production, it was real-ized that the previous bulk sorting system delayedprocessing of single patient tubes in an unpredict-able and randomway. For this reason, Sysmex andFagtek (now TIMEDICO) were asked to cooperatein producing a robot for receiving samples follow-ing the principle of “first in, first out” (FIFO)3 toachieve a total turnaround time (ToTAT) of <60minfrom phlebotomy to the practitioner receiving theresult (Fig. 1). This robot was installed in November2015 at the Lillebaelt Hospital and connected tothe newly developed GLP conveyer system in thelaboratory (see Supplemental Figs. B–D in the on-line Data Supplement).Although the quality of the analytical test results
on the most frequent components has beentested in the Tempus600® tube system (1), it wasalso necessary to validate the Tempus600 systemwhen combined with the FIFO Sysmex GLP RobotReception System. This study was carried out with
3Nonstandardabbreviations: FIFO,first in,first out; ToTAT, total turnaround time; PO2, partial pressure of oxygen; PCO2, partial pressure of carbondioxide; TAT, turnaround time; PTS, pneumatic tube system.
100 patients who agreed to donate blood to thistechnical validation, allowing the laboratory to per-form analysis on the 89most frequently requestedanalytes.
MATERIALS AND METHODS
Patients
One hundred patients from the hospital's out-patient clinics were included. The patients werereferred from outpatient wards of general practi-tioners or specialists without consideration to di-agnosis and had a broad mix of diseases. One to10 patients were sampled per day fromMarch 3 toApril 13, 2016. According to Danish law, this inves-
tigation is regarded as a technical/quality assur-ance project exempt from jurisdiction under theScience Ethics Committee system. The investiga-tion is in compliance with the Declaration ofHelsinki ethical principles. The Science EthicsCommittee system need not approve such a qualityassurance project and only oral consent is required.Eachpatientwasasked tovoluntarilydonateanextra10 tubes of blood (maximum 40mL blood).
Blood samples
Samples were submitted for a panel of analysesconsisting of 90% of the most frequently orderedtests at the laboratory (Table 1). The panel ofcomponents was collected from all patients using
Fig. 1. TAT of 2012 versus 2015, morning round.The colored curves indicate the TAT in 2012 (blue) and 2015 (red). The lower blue and red curves indicate the time when 80%of the sampling has beenperformed,whereas theupper blue and red curves indicatewhen80%of themorning round resultshas been approved by the medical technologists. The Tempus600/Sysmex GLP Robot Reception System has decreased theToTAT from sampling the patient to the doctor receiving the result from 2–3 hours to less than 60 minutes.
a butterfly set (21-gauge needle). The analyseswere all requested through the web-based labora-tory informationmanagement system. This systemprints labels and barcodes locally to assure thecorrect tubes were labeled before sampling thepatient. Duplicate blood samples (A and B) wereobtained according to GP41-A6 guidelines pro-vided by CLSI (2), except that the tubes were la-beled before the blood sampling. The phlebotomywas performed by the same trained medical tech-nologist on every occasion. Five different bloodtubes were drawn for each set (A and B). One pink(fluoride and citrate) from Venosafe, Terumo, and1 purple (K2EDTA), 1 blue (sodium citrate), and 2green (lithium heparin) tubes from BectonDickinson (all with a diameter of 1.5 cm and alength of 8.3 cm), for a total of 10 tubes corre-sponding to 40 mL blood. To avoid biological andsampling variation, the same venipuncture wasused to collect all 10 samples, and all tubes werefilled to the specified full capacity.Fifty patients had the Tempus samples (A) drawn
first and the courier samples (B) second; for theother 50 patients, the order of draw was reversed.The blood samples were always sent from thesame Tempus station and the courier always usedthe same route from the ward to the laboratory,carrying the samples in an upright position to thelaboratory within 3–5min. The Tempus600 systemwas from TIMEDICO, the FIFO Reception Robotfrom Sysmex, and the GLP conveyer belt systemfrom GLP Systems.
Tempus600
The blood tubes were transported via the Tem-pus600 from the outpatient clinic 4 floors up to thelaboratory, a distance of about 200 m. This stepwas done with a speed of around 10 m/s (400 me-ters per 30–40 s). (For further information aboutthe Tempus system, visit http://www.tempus600.com.)
Analytical procedure
After arrival to the laboratory, all blood sampleswere treated in parallel, and the paired samples Aand B were analyzed at the same time to avoidvariation due to analytical drift and changes in ana-lyte concentration due to differences in time andtemperature. The tubes were placed on the GLPtransport system (GLP Systems) by either theSysmex FIFO Reception Robot (Tempus tubes) ormanually by the courier (carried tube). The GLPtransport system then transferred the blood tubesto the centrifuges and the analysis equipment. Theanalysis equipment used was the Sysmex XN-9000hematology system, the Sysmex CS-5100 coagula-tion system, the Roche Cobas 8000 chemistry sys-tem, and the Radiometer ABL 827 blood gassystem.The 5 different blood tubes were then pro-
cessed for specific analytical applications. The pinkand 1 of the green test tubes were centrifuged at2000g for 10 min, 20 °C, before they were sent tothe Cobas 8000. The other green tube was manu-ally collected from the GLP track and brought tothe ABL 827 where the analysis was performed.The blue tubewas centrifuged at 2500g for 15min,20 °C, for coagulation testing, and the purple tubewas sent directly to the Sysmex XN-9000 withoutcentrifugation.As mentioned earlier, the blood sample sets
were drawn at the same time and from the samepuncture for each person; therefore, the biologicaland sampling variation will not affect the transportcomparisons.
Statistics
All statistical analysis data were performed us-ing Microsoft Excel for Mac 2011, version 14.6.3.Comparisons between the 2 transport forms
were made using a modified version of the differ-ence plots described by Bland and Altman (3), us-ing values obtained by courier transport as the
abscissa and difference between the Tempus andcourier results as the ordinate. Limits show thecombined 95% uncertainty of the difference be-tween 2 analytical results when only the analyticalwithin-run uncertainty (repeatability) has influenceon the difference between the courier andTempus samples using repeatability data from thesingle kit inserts. The variance (SD2) of this differ-ence can be expressed:
SDdiff2 � SDanal1
2 � SDanal22 � 2 × SDanal,
2
SDdiff � √2 × SDanal2 � √2 × SDanal,
where anal1 and anal2 indicate the two analyses(in our case, they are the same analysis).We assume that the difference in results, if the
Tempus/GLP does not increase variation or causea systematic bias, is normally distributed with amean of 0, which means that the 0.025 quantile is1.96. The limits for the combined uncertainty of95% are therefore:
Acceptable difference ≤ 1.96 × √2 × SDanal.
For purposes of this study, we used the SD fornormal values over the observed concentrationrange. Those that have a constant SD over the con-centration range have horizontal 95% CI limits.For practical reasons, we assumed a constant
SD for all analytes, although there may be somemild variation across the measurement range.If the transport process does not influence the
analytic outcome, 95% of the residual differenceswill lie within the 95% CI for the difference (3). Ifmore than 5% of the results exceed the limits, thisindicates that there is a difference between the 2transport systems. This scenario could be due tobias introduced by either of the transport forms,which would result in a systematic difference (3) orlarger than expected variation, if Tempus induceda random influence.The SD within-run for all hematology analytes
was evaluated in the following way, as the manu-
facturer only stated the intermediate variance(SDtotal) in the kit inserts:
SDtotal2 � SDwithin
2 � SDbetween2,
where SDbetween is the variance between runs.
assumption: SDwithin2 � SDbetween
2,
SDwithin � � SDtotal2
2 .
The 95% CI limits of difference were, if only de-termined by the 2 measurements within-run vari-ation, again calculated by the equation:
95% CI � ±1.96 × √2 × SDwithin.
A paired t-test on the distribution of results derivedfrom the courier vs Tempuswas performed. For differ-ences in population SD, the Bartlett test was used.
RESULTS
Table1 shows thepopulationmeanandSD for the2 transport forms as well as the difference and theSD for the analysis at Vejle Hospital. Moreover,the P values for the difference of population meanand SD are shown. Only results from patients whereboth tubes (Tempus and courier) were availablewere included. Samples from3patientswere unableto be analyzed. One antithrombin result did not getdeliveredcorrectly andwasnot repeated.Becauseofthe size of the thrombocytes of one of the patients,the platelet distribution width was not measured.Two tubes from the same patient did not get fullyanalyzed because the blood samples were very li-pemic. The samples should have been ultracentri-fuged but were discarded instead. Therefore, theresults forantithrombin, internationalnormalized ra-tio, and activated partial thromboplastin time arelacking for a single patient.Difference plots between the Tempus and courier
transport were performed for all analyses. Only se-lected analyses are shown here (Fig. 2A–G; for therest see Supplemental Data 1 in the online DataSupplement).
Only a few analytes (Table 1) showed statisticallysignificant differences between population meansfor the 2 forms of transport. The SD for the popu-lation variation differed significantly for even feweranalytes (Table 1).With the exception of oxyhemoglobin, oxygen sat-
uration, partial pressure of oxygen (PO2), and partialpressure of carbon dioxide (PCO2), the pneumatictube transport systemdid not have a clinicallymean-ingful impact on any of the substances tested.
DISCUSSION
The use of point-of-care testing has increasedduring the past few years because it reduces turn-around time (TAT). However, with installation ofpneumatic tube systems (PTSs), the TAT is opti-mized, the analytical quality is improved, and thecosts are reduced (4, 5). Our goal was to validatethe new Tempus600 PTS combined with the FIFOSysmex GLP Robot Reception System. This stepwas completed by analyzing the 89 of the mostfrequently analyzed and critically relevant compo-nents from 100 randomly selected patients.In general, Table 1 shows that there was no dif-
ference between population means and distribu-tion width for the majority of analytes, whethertransported by courier or the tube system. Thus,the tube system does not induce a systematic orpreanalytical random error on results.Oxygen saturation, oxyhemoglobin, and the PO2
showed unacceptable deviation from a clinical pointof view (Fig. 2A–C). For example, a severely loweredoxygen saturation of 60% could read as 90% aftertube transport. For oxyhemoglobin, the PO2 coulddeviate by as much as 4 kPa at a value of 8, which isconsidered a critical value in arterial blood. Thesemeasurements were, however, done on venousblood. If it can be shown that the venous PO2 mea-surement after tube transport could detect themostsevere forms of oxygen deficiency in acute admis-sions patients, then in the future it might be possibleto use PO2 measured in venous blood after proper
validation. The PCO2 differences between courier-and Tempus-transported venous blood were rela-tively small (Fig. 2D). Although fromananalytical qual-ity point of viewacceptable limitswere exceeded, themeasurements were deemed clinically acceptablefor assessing patients with obstructive lung diseaseby hospital pulmonologists.A special focus is potassium, which has previously
been reported as very sensitive to temperature,based on time and transport technology (6). How-ever, courier andTempus transport are equally goodand clinically pose no problems (Fig. 2E). The sameissue could be relevant for lactate dehydrogenase.As Fig. 2F shows, there are a few outliers in the refer-ence range, which are probably patient specific. Ingeneral, it can be concluded that lactate hydroge-nase measurement is reliable when transported bythe Tempus system. However, if values are unex-pectedly high, selected samples might require man-ual transport to assure accuracy.The hemolytic index, which is a measure of free
hemoglobin in plasma and therefore an indicator formechanical injury to erythrocytes during transport,implies that transport in a pressurized tube trans-port system has some influence on hemolysis. Six ofthe samples transportedby the Tempusand2 trans-ported by the courier had detectable hemolysis.However, all but a single valueof plasmahemoglobinwerebelow13μmol/L (20mg/dL). Somepatients areespecially prone to an increase inhemolytic indexby,for example, impacting analyses such as lactate de-hydrogenase (see Supplemental Data 1 in the onlineData Supplement). In our study, none of the in-creased LDH results were caused by an increase inhemolytic index, but some of the measured differ-ences in LDH between Tempus and courier sampleresults were attributable to increased hemolytic in-dex during transport. The conclusion is that thesesamples can be transported because the safety sys-tem built into the instruments will alert users of ahigh hemolytic index and the necessity for specialsampling andmanual transport followed by immedi-ate analysis to get reliable results.
Fig. 2. Difference plots between the Tempus and courier transport for selected analyses.The courier transport is the abscissa, and the Tempus result minus the courier result is the difference. Limits show thecombined 95% uncertainty of the difference between 2 analytical results, if only the analytical uncertainty has influence ondifference between the courier and Tempus samples. The vertical lines indicate the reference interval in venous blood.Oxyhemoglobin = [O2Hb]/[O2Hb +HHb], whereHHb is deoxyhemoglobin. Oxygen saturation = [O2Hb]/[total Hb], where totalHb is the sum of oxy-, deoxy-, met-, sulf-, and carboxyhemoglobin. ABL indicates that the analysis was performed on aRadiometer ABL 827 blood gas system. mol. fr., mol fraction; (vB), venous blood; P, plasma.
In general, we found what was already known,namely that certain variables and components weresensitive to tube transport, especially arterial bloodgas results and parameters related to hemolysis ofred blood cells (7–9). By recruiting patients admittedto our ambulatory service for blood sampling, wewere able to include patients that had a variety ofdiseases. Although it is seenthat forsomeparameters,for example, ethanol, digoxin, and international nor-malized ratio, the values are quite low; therefore, wewerenotabletodocumentthat thesecomponentscanbe transported safely in the Tempus system.The results are in concordance with the
previously published study by Hastrup et al.
(1), though this was a preliminary investigationof the feasibility of the system in routinepractice.We conclude that the Tempus600 system canbe
used for transport of themajority of routinely usedanalytical tests in a general hospital setting. Thisstep is especially important for troponin for thediagnosis of acute myocardial infarction and lac-tate for assessing septicemia.While decreased TATmay be achieved by traditional vacuum systemswith container transport, systems like theTempus600 can be installed in a fraction of thetime and cost, with little compromise in analyticalquality and clinical requirements.
Author Contributions: All authors confirmed they have contributed to the intellectual content of this paper and havemet the following4 requirements: (a) significant contributions to the conception and design, acquisition of data, or analysis and interpretation of data; (b)drafting or revising the article for intellectual content; (c) final approval of the published article; and (d) agreement to be accountable forall aspects of the article thus ensuring that questions related to the accuracy or integrity of any part of the article are appropriatelyinvestigated and resolved.
Authors’ Disclosures or Potential Conflicts of Interest:Uponmanuscript submission, all authors completed the author disclosureform. Employment or Leadership: None declared. Consultant or Advisory Role: None declared. Stock Ownership: Nonedeclared. Honoraria: None declared. Research Funding: I. Brandslund, I.B. Andersen, Timedico. Expert Testimony: Nonedeclared. Patents: None declared.
Role of Sponsor: The funding organizations played no role in the design of study, choice of enrolled patients, review andinterpretation of data, or preparation or approval of manuscript.
Acknowledgments: Special thanks go to medical technologist Monika Tusinska for performing the blood sampling. MScITBiostatistician Henry Christensen is thanked for statistical advice and testing.
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