Pneumatic Tube Delivery System for Blood Samples Reduces Turnaround Times Without Affecting Sample Quality

doi:10.1016/j.jen.2005.11.013

Journal of Emergency Nursing

Volume 32, Issue 2, April 2006, Pages 139-143

https://doi.org/10.1016/j.jen.2005.11.013 Get rights and content

Study objectives

In this study, blood samples from ED patients that were delivered to the laboratory by a pneumatic tube delivery system and by a human courier were compared for timeliness and quality of results.

Methods

We studied all consecutive measurements of serum hemoglobin and potassium ordered from 2 emergency departments of a multisite tertiary care hospital system, one with a pneumatic tube system and the other using human couriers. Turnaround time was measured from the time that the test was ordered by the physician to the time the result was reported on the hospital information system. Hemolysis was measured with use of a standardized, validated method.

Analysis

Times were normalized by log transformation (ln [minutes + 1]), and a comparison of sites was conducted using analysis of variance. Hemolysis rates of the 2 delivery systems were compared by χ².

Results

There was no significant difference in hemolysis rate between the 2 methods of delivery (7/121 [5.79%] with a pneumatic tube system and 20/200 [10%] with a human courier). When delivered with a pneumatic tube system, the mean turnaround times (with ranges) for both hemoglobin (33 minutes [4-230]) and potassium (64 [34-208]) were shorter than those delivered by a human courier (43 minutes [3-150] and 72 [28-213], respectively).

Conclusion

The use of a pneumatic tube delivery system for transporting blood samples from the emergency department to the laboratory can significantly reduce the turnaround times of results without a reduction in sample quality.

Section snippets

Ethics

This quality assessment study did not involve human subjects or experiments and therefore was deemed by our hospital and university Review Ethics Board to be exempt from formal approval. Identification of blood samples was removed as the data for each sample were entered into a computer database for analysis. This process maintained the confidentiality of patient information by eliminating all patient identifiers from each sample.

Setting

The setting was 2 emergency departments of a multisite, tertiary

Results

Table 1 illustrates that the turnaround time for hemoglobin was significantly less than that for serum potassium (F[1,660] = 406, P < .001). More importantly for the current discussion, the same table illustrates that the turnaround time for the PTS was significantly less than that of a human courier system (F[1,66] = 136, P < .001). Finally, the hemolysis rate of 7/121 (5.8%) observed with a PTS did not differ from the rate of 20/200 (10%) observed with a human courier (χ² = .174, P > .15).

Discussion

The results of this study demonstrate that transportation of blood specimens from the emergency department to the laboratory via a PTS can be time effective without compromising the quality of the samples. A previous study simultaneously comparing TATs via a human courier and a PTS found no statistical difference between the two.⁶ However, students were employed specifically for the purpose of carrying the specimens to the laboratory in that study, presumably as soon as the specimens were

Conclusion

The use of a pneumatic tube delivery system for transporting blood samples from the emergency department to the laboratory can significantly reduce the TATs of results without a reduction in sample quality.

Christopher M.B. Fernandes is Professor and Head of Emergency Medicine, McMaster University, Hamilton, Ontario, Canada.

References (15)

CMB Fernandes et al.
Root cause analysis of laboratory delays to an emergency department
J Emerg Med
(1997)
TO Stair et al.
Hemolysis of blood specimens transported from ED to laboratory by pneumatic tube
Am J Emerg Med
(1995)
M Altieri et al.
Point of care testing
Clin Pediatr Emerg Med
(2001)
P Howanitz et al.
Emergency department stat test turnaround times
Arch Pathol Lab Med
(1992)
CMB Fernandes et al.
Root cause analysis of delays for laboratory tests on emergency department patients
Can J Emerg Med
(2004)
M Green
Successful alternatives to alternate site testing. Use of a pneumatic tube system to the central laboratory
Arch Pathol Lab Med
(1995)
D Pragay et al.
Evaluation of an improved pneumatic-tube system suitable for transportation of blood specimens
Clin Chem
(1974)

There are more references available in the full text version of this article.

Cited by (60)

False decrease of high-sensitivity cardiac troponin T assay in pneumatic tube system samples
2019, Clinica Chimica Acta
The pneumatic tube system (PTS) is widely established in clinical laboratories. We aimed to evaluate the impacts of PTS on high-sensitivity cardiac troponin T (hs-cTnT) assays.
The hemolysis distribution of hs-cTnT PTS specimens from emergency department (ED) were determined by hemolysis index (HI). Grouped samples from 15 healthy volunteers were delivered to the laboratory via manual delivery (MD) or PTS. Interference studies were conducted to access the influence of different hemolysis degrees on hs-cTnT assays.
7.26% PTS specimens from ED were hemolyzed in clinic. Compared with MD samples, we found highly elevated free plasma hemoglobin (Hb) in PTS samples. Hs-cTnT was interfered negatively with free Hb (R = -0.625, P < .001), and it was also validated in interference studies (R ≥ -0.820, all P ≤ .001). Clinically significant bias occurred in each hs-cTnT concentration at 100 mg/dl free Hb (Bias≥ − 13.85%, all P < .05). Moreover, bias of hs-cTnT assays at 50 mg/dl free Hb was approaching 10%, especially at 30 ng/l hs-cTnT concentration (Bias: -11.72%, P < .001).
PTS could increase the frequency of specimen hemolysis which might cause false decrease in hs-cTnT assays. Hence, clinicians should be aware of the increased measurement bias in hs-cTnT from hemolyzed PTS samples with free Hb ≥50 mg/dl.
Drone inflight mixing of biochemical samples
2018, Analytical Biochemistry
Autonomous systems for sample transport to the laboratory for analysis can be improved in terms of timeliness, cost and error mitigation in the pre-analytical testing phase. Drones have been reported for outdoor sample transport but incorporating devices on them to attain homogenous mixing of reagents during flight to enhance sample processing timeliness is limited by payload issues. It is shown here that flipping maneuvers conducted with quadcopters are able to facilitate complete and gentle mixing. This capability incorporated during automated sample transport serves to address an important factor contributing to pre-analytical variability which ultimately impacts on test result reliability.
Causes, consequences and management of sample hemolysis in the clinical laboratory
2017, Clinical Biochemistry
Citation Excerpt :
Transport of blood samples from the location of blood collection to the laboratory may also be associated with hemolysis. Fernandes et al. reported a significantly lower percentage of troublesome hemolysis when centrifugation took place at the site of collection rather than in the laboratory [46]. Exposure of blood samples to extreme temperatures during transport and long transport duration may cause hemolysis [5,46].
Preanalytical hemolysis of blood samples is a common problem in medical practice, especially in emergency departments. Several potential influences on sample hemolysis have been investigated, including sampling techniques, centrifugation and sample transport. In particular, the use of intravenous catheters and the vacuum sampling technique have often been demonstrated to provoke hemolysis. Other factors playing a role include the use of inappropriate puncture sites, complicated blood sampling, prolonged tourniquet application, underfilling of tubes and excessive shaking of specimens. Training of phlebotomists can play a pivotal role in overcoming these issues. A sample may also undergo hemolysis at the point of centrifugation, more specifically when centrifugation lasts too long or is done repeatedly. Pneumatic tube system (PTS)-transported samples tend to be more strongly affected by hemolysis compared to hand-carried ones, though whether this difference is clinically relevant remains questionable. The velocity at which the sample moves, the distance it covers and the shock forces it sustains all determine to what extent hemolysis occurs during PTS transport. The use of cushion inserts in the carrier to stabilize the samples and the presence of a gel separator in the transported serum tubes may prevent PTS-induced hemolysis. Finally, there is considerable variation between patients in the extent to which samples are prone to hemolysis. Sample hemolysis leads to unreliable laboratory results, delayed diagnosis and patients suffering avoidable discomfort. Specifically, hemolysis may interfere with laboratory results due to release of intracellular components, dilution effects, proteolysis and interference with analytical techniques. There is ongoing debate about how laboratories should deal with results altered by hemolysis. Laboratory specialists should clearly communicate with the ordering clinicians in order to make an informed decision about how to interpret hemolysis-affected analytical results. This review looks into current evidence concerning the causes and consequences of in vitro hemolysis, and aims to explain how to deal with it.
Effects of one directional pneumatic tube system on routine hematology and chemistry parameters; A validation study at a tertiary care hospital
2017, Practical Laboratory Medicine
Citation Excerpt :
In this study, there were no statistical significant differences for CBC, WBC differential count, and ESR between both methods. Results of the present study correspond well with those of the earlier studies which reported that PTS does not affect hematology parameters [3,9–11]. A recent study found no statistical differences for CBC, and ESR between the PTS and hand-carried method [10].
The validation of sample stability through pneumatic tube system (PTS) is essential. The objective of this study was to evaluate the effects of PTS transportation on laboratory results.
Paired EDTA and SST blood samples were collected from 56 randomly selected patients. Laboratory parameters were compared between PTS group and hand-delivered group.
No statistical differences were observed for complete blood counts, white blood cell differential parameters, erythrocyte sedimentation rate and most chemistry parameters between PTS and hand-delivered transport procedures. Mean platelet volume results obtained from samples transported through PTS were lower than that obtained from samples transported through hand-delivered method (P = 0.001). The results of aspartate aminotransferase (P = 0.000), lactate dehydrogenase (P = 0.000), and hemolysis index (P = 0.000) from PTS group were higher than that from hand-delivered group.
All laboratories should validate the stability of the results from samples according to transportation method.
Multiple pre- and post-analytical lean approaches to the improvement of the laboratory turnaround time in a large core laboratory
2017, Clinical Biochemistry
Core laboratory (CL), as a new business model, facilitates consolidation and integration of laboratory services to enhance efficiency and reduce costs. This study evaluates the impact of total laboratory automation system (TLA), electric track vehicle (ETV) system and auto-verification (AV) of results on overall turnaround time (TAT) (phlebotomy to reporting TAT: PR-TAT) within a CL setting.
Mean, median and percentage of outlier (OP) for PR-TAT were compared for pre- and post-CL eras using five representative tests based on different request priorities. Comparison studies were also carried out on the intra-laboratory TAT (in-lab to reporting TAT: IR-TAT) and the delivery TAT (phlebotomy to in-lab TAT: PI-TAT) to reflect the efficiency of the TLA (both before and after introducing result AV) and ETV systems respectively.
Median PR-TATs for the urgent samples were reduced on average by 16% across all representative analytes. Median PR-TATs for the routine samples were curtailed by 51%, 50%, 49%, 34% and 22% for urea, potassium, thyroid stimulating hormone (TSH), complete blood count (CBC) and prothrombin time (PT) respectively. The shorter PR-TAT was attributed to a significant reduction of IR-TAT through the TLA. However, the median PI-TAT was delayed when the ETV was used. Application of various AV rules shortened the median IR-TATs for potassium and urea. However, the OP of PR-TAT for the STAT requests exceeding 60 min were all higher than those from the pre-CL era.
TLA and auto-verification rules help to efficiently manage substantial volumes of urgent and routine samples. However, the ETV application as it stands shows a negative impact on the PR-TAT.
The Effect of Pneumatic Tube Systems on the Hemolysis of Biochemistry Blood Samples
2017, Journal of Emergency Nursing
Pneumatic tube systems (PTSs) are widely used in many hospitals because they lead to reduced turnaround times and cost efficiency. However, PTSs may affect the quality of the blood samples transported to the laboratory. The aim of this study was to investigate the effect of the PTS used in our hospital on the hemolysis of the biochemical blood samples transported to the laboratory.
A total of 148 samples were manually transported to the laboratory by hospital staff, 148 samples were transported with the PTS, and 113 were transported with the PTS without use of sponge-rubber inserts (PTSws). Hemolysis rates and the levels of biochemical analytes for the different transportation methods were compared.
No significant difference was found between the samples transported manually and with the PTS with regard to hemolysis rate and the levels of biochemical analytes. However, the samples transported with the PTSws showed a significant difference compared with the samples transported manually and with the PTS with regard to hemolysis rate and potassium and lactate dehydrogenase levels. The percentages of the samples that exceeded the permissible threshold for the hemolysis among the samples transported manually, with the PTS, and with the PTSws were 10%, 8%, and 47%, respectively.
A PTS can be used safely for transporting biochemistry blood samples to the laboratory. However, a sponge-rubber insert that holds sample tubes must be used with the PTS to prevent the hemolysis of blood samples.

View all citing articles on Scopus

Christopher M.B. Fernandes is Professor and Head of Emergency Medicine, McMaster University, Hamilton, Ontario, Canada.

Andrew Worster is Clinical Assistant Professor, Emergency Medicine, Hamilton Health Sciences and McMaster University, and Clinical Assistant Professor, Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada.

Kevin Eva is Assistant Professor, Department of Clinical Epidemiology and Biostatistics, McMaster University, Hamilton, Ontario, Canada.

Stephen Hill is Assistant Professor, Hamilton Regional Laboratory Medicine Program and Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, Canada.

Catherine McCallum is Quality Manager, Hamilton Regional Laboratory Medicine Program, Hamilton, Ontario, Canada.

: Presented at the American College of Emergency Physicians Research Forum, Boston, Massachusetts, October 2003.

View full text

ResearchPneumatic Tube Delivery System for Blood Samples Reduces Turnaround Times Without Affecting Sample Quality

Study objectives

Methods

Analysis

Results

Conclusion

Section snippets

Ethics

Setting

Results

Discussion

Conclusion

J Emerg Med

Am J Emerg Med

Clin Pediatr Emerg Med

Emergency department stat test turnaround times

Arch Pathol Lab Med

Root cause analysis of delays for laboratory tests on emergency department patients

Can J Emerg Med

Successful alternatives to alternate site testing. Use of a pneumatic tube system to the central laboratory

Arch Pathol Lab Med

Evaluation of an improved pneumatic-tube system suitable for transportation of blood specimens

Clin Chem

Research
Pneumatic Tube Delivery System for Blood Samples Reduces Turnaround Times Without Affecting Sample Quality