Determination of Hemolysis Thresholds by the Use of Data Loggers in Pneumatic Tube Systems

Comparison of a two-step Tempus600 hub solution single-tube vs. container-based, one-step pneumatic transport system

OBJECTIVES

Efficient and timely transportation of clinical samples is pivotal to ensure accurate diagnoses and effective patient care. During the transportation process, preservation of sample integrity is crucial to avoid pre-analytical aberrations on laboratory results. Here, we present a comparative analysis between a two-step Tempus600 hub solution single-tube and a one-step, container-based pneumatic transport system (PTS) from Airco, for the in-house transportation of blood samples.

METHODS

Ten blood samples from healthy volunteers were split in 10 mL collection tubes filled at full or half capacity for transportation with the two PTS (about 250 m). To compare the impact of transportation, markers of hemolysis such as lactate dehydrogenase (LDH), potassium (K+), and the hemolysis index (HI), were determined. Additionally, differences in HI in routine samples and repeated transportation was investigated. To assess and compare the mechanistic impact profiles, we recorded the acceleration profiles of the two PTS using a shock data logger.

RESULTS

Transportation using the Tempus600 hub solution resulted in 49 and 46 % higher HI with samples filled to total or half capacity, respectively. Routine samples transported with the Tempus600 hub solution showed a higher median HI by 23 and 33 %. Additionally, shock logger analysis showed an elevated amount of shocks (6.5 fold) and shock intensities (1.8 fold).

CONCLUSIONS

The Tempus600 hub solution caused an increased number of unreportable LDH or K+ results based on the hemolysis index. However, it was only statistically significant for LDH (p<0.01 and p<0.08) - while the comparisons for K+ were not statistically significant (p<0.28 and p<0.56).

Pitfalls in the diagnosis and management of acid-base disorders in humans: a laboratory medicine perspective

Diagnostic errors affect patient management, and as blood gas analysis is mainly performed without the laboratory, users must be aware of the potential pitfalls. The aim was to provide a summary of common issues users should be aware of.A narrative review was performed using online databases such as PubMed, Google Scholar and reference lists of identified papers. Language was limited to English.Errors can be pre-analytical, analytical or post-analytical. Samples should be analysed within 15 min and kept at room temperature and taken at least 15-30 min after changes to inspired oxygen and ventilator settings, for accurate oxygen measurement. Plastic syringes are more oxygen permeable if chilled. Currently, analysers run arterial, venous, capillary and intraosseous samples, but variations in reference intervals may not be appreciated or reported. Analytical issues can arise from interference secondary to drugs, such as spurious hyperchloraemia with salicylate and hyperlactataemia with ethylene glycol, or pathology, such as spurious hypoxaemia with leucocytosis and alkalosis in hypoalbuminaemia. Interpretation is complicated by result adjustment, for example, temperature (alpha-stat adjustment may overestimate partial pressure of carbon dioxide (pCO2) in hypothermia, for example), and inappropriate reference intervals, for example, in pregnancy bicarbonate, and pCO2 ranges should be lowered.Lack of appreciation for patient-specific and circumstance-specific reference intervals, including extremes of age and altitude, and transformation of measurements to standard conditions can lead to inappropriate assumptions. It is vitally important for users to optimise specimen collection, appreciate the analytical methods and understand when reference intervals are applicable to their specimen type, clinical question or patient.

An Overview of Pre-Analytical Factors Impacting Metabolomics Analyses of Blood Samples

Discrepant sample processing remains a significant challenge within blood metabolomics research, introducing non-biological variation into the measured metabolome and biasing downstream results. Inconsistency during the pre-analytical phase can influence experimental processes, producing metabolome measurements that are non-representative of in vivo composition. To minimize variation, there is a need to create and adhere to standardized pre-analytical protocols for blood samples intended for use in metabolomics analyses. This will allow for reliable and reproducible findings within blood metabolomics research. In this review article, we provide an overview of the existing literature pertaining to pre-analytical factors that influence blood metabolite measurements. Pre-analytical factors including blood tube selection, pre- and post-processing time and temperature conditions, centrifugation conditions, freeze-thaw cycles, and long-term storage conditions are specifically discussed, with recommendations provided for best practices at each stage.

Jerk (d(acceleration)/dt) as an operative variable in pneumatic tube transport (PTT)

BACKGROUND

Jerk, the rate of change of acceleration (d(acceleration)/dt), is a known operative variable in public transportation safety, but this term has never appeared in the literature regarding pneumatic tube transport (PTT) and specimen integrity. We investigated profiles of acceleration and jerk for 2 PTT routes within our hospital system.

METHODS

Acceleration data were collected for PTT for 2 routes (A, B) using an accelerometer. Acceleration vectors (a) were analyzed in terms of distributions of jerk (da/dt), and distributions of θ, the angle between successive acceleration vectors.

RESULTS

Routes A and B had transit times of approximately 300 s. Acceleration vectors (a) ranged in magnitude from 0 to 8 g. For B, a > 1.2 g comprised 29.0% of results, compared to 13.5% of results for A (ratio = 2.1). Jerk ranged from 0 to 94 g/s. For B, jerk > 0.5 g/s comprised 71.9% of results, compared to 32.5% of results for A (ratio = 2.2). θ ranged from 0 to 180 degrees. For B, θ > 5 degrees comprised 59.3% of results, compared to 26.6% of results for A (ratio = 2.2).

CONCLUSION

Differences in distribution in acceleration, jerk, and θ ran in parallel as variables for comparison between 2 PTT routes. Jerk and θ are likely to be operative variables in effects of PTT.

Comparison of the speed and quality of innovative and traditional pneumatic tube system transport outside of an emergency laboratory

Background

Ensuring the rapidity and accuracy of emergency laboratory test results is especially important to save the lives of patients with acute and critical conditions. To better meet the needs of clinicians and patients, detection efficiency can be improved by reducing extra-laboratory sample turnaround times (TATs) through the use of innovative pneumatic tube system (PTS) transport for sample transport. However, concerns remain regarding the potential compromise of sample quality during PTS transit relative to that occurring with manual transportation. This study was performed to evaluate the efficacy of an innovative PTS (Tempus600 PTS) relative to a traditional PTS in terms of sample transit time, sample quality, and the concordance of analytical results with those obtained from manually transported samples.

Methods

In total, 30 healthy volunteers aged >18 years were recruited for this study, conducted for five consecutive days. Venous blood samples were collected from six volunteers per day at fixed timepoints. From each volunteer, nine blood samples were collected into tubes with tripotassium ethylene diamine tetraacetic acid anticoagulant, tubes with 3.2 % sodium citrate, and serum tubes with separation gel (n = 3 each) and subjected to all tests conducted in the emergency laboratory in our hospital. 270 blood samples from 30 healthy volunteers were transported and analyzed, yielding 6300 test results. The blood samples were divided randomly into three groups (each containing one tube of each type) and transported to the emergency laboratory manually and with Tempus600 PTS and conventional Swisslog PTS, respectively. The extra-laboratory TATs, sample quality, and test results of the transported blood samples were compared.

Results

The sample quality and test results did not differ according to the delivery method. The TAT was much shorter with the Tempus600 than with the other two transport modes (58.40 ± 1.52 s vs. 1711.20 ± 77.56 s for manual delivery and 146.60 ± 1.82 s for the Swisslog PTS; P = 0.002).

Conclusion

Blood sample transport with the Tempus600 PTS significantly reduced the extra-laboratory TAT without compromising sample quality or test result accuracy, thereby improving the efficiency of sample analysis and the services provided to clinicians and patients.

Diagnostic sample transport via pneumatic tube systems: data logger and their algorithms are sensitive to transport effects

OBJECTIVES

Many hospitals use pneumatic tube systems (PTS) for transport of diagnostic samples. Continuous monitoring of PTS and evaluation prior to clinical use is recommended. Data loggers with specifically developed algorithms have been suggested as an additional tool in PTS evaluation. We compared two different data loggers.

METHODS

Transport types - courier, conventional (cPTS) and innovative PTS (iPTS) - were monitored using two data loggers (MSR145® logger, CiK Solutions GmbH, Karlsruhe, Germany, and a prototype developed at the University Medicine Greifswald). Data loggers differ in algorithm, recording frequencies and limit of acceleration detection. Samples from apparently healthy volunteers were split among the transport types and results for 37 laboratory measurands were compared.

RESULTS

For each logger specific arbitrary units were calculated. Area-under-the-curve (AUC)-values (MSR145®) were lowest for courier and highest for iPTS and increased with increasing recording frequencies. Stress (St)-values (prototype logger) were obtained in kmsu (1,000*mechanical stress unit) and were highest for iPTS as well. Statistical differences between laboratory measurement results of transport types were observed for three measurands sensitive for hemolysis.

CONCLUSIONS

The statistical, but not clinical, differences in the results for hemolysis sensitive measurands may be regarded as an early sign of preanalytical impairment. Both data loggers record this important interval of beginning mechanical stress with a high resolution indicating their potential to facilitate early detection of preanalytical impairment. Further studies should identify suitable recording frequencies. Currently, evaluation and monitoring of diagnostic sample transport should not only rely on data loggers but also include diagnostic samples.

Influence of pneumatic tube delivery system on laboratory results

INTRODUCTION

The pneumatic tube system (PTS) is an automated and fast modality of transportation of biological samples, but it has been reported to induce preanalytical errors.

AIM

To study the influence of transportation by PTS on biochemistry tests which are particularly sensitive to haemolysis and atmospheric pressure variation.

MATERIALS AND METHODS

We compared laboratory results of arterial blood gas, sodium, potassium, chloride, lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, glucose and haemolysis index of samples conveyed simultaneously by PTS and by courier.

RESULTS

We recruited 30 patients from the sampling room and 40 patients from the intensive care unit. Transport through PTS resulted in a significant increase in aspartate aminotransferase and potassium without exceeding the limits of acceptability. Potassium was significantly more increased for samples transported in a higher speed line (p = .048) but without exceeding the limits of acceptability. No significant impact was noted on haemolysis indices. The pO2 variations due to PTS transportation exceeded the limit of acceptability with significant intra-individual variations.

CONCLUSION

Our PTS is validated for biochemistry tests results. It reduces turnaround times without affecting sample quality. However, the interpretation of arterial blood gas results should be careful for samples transported by PTS.

Evaluation of a rail logistics transmission system for the transportation of blood components within a medical centre

BACKGROUND AND OBJECTIVES

Rail logistics transmission systems (RLTSs) are commonly used for the transportation of blood samples, pathological specimens and other medical materials in many hospitals, as they are rapid, secure, cost-effective and intelligent. However, few studies have evaluated blood component transportation from blood banks to the patient care areas of hospitals using RLTS. In this study, we evaluate the RLTS used for the transportation of blood components within a medical centre.

MATERIALS AND METHODS

The dispatch of blood components, including packed red blood cells (pRBCs), fresh frozen plasma (FFP), cryoprecipitate and platelet units, from a blood bank to critical care areas or general wards was done using RLTS. Parameters such as the delivery time, temperature, physical integrity and blood component quality were evaluated via analytical testing using specimens obtained before and after transportation by RLTS.

RESULTS

The turnaround time and temperature of all tested blood units via RLTS transportation were able to meet the clinical demands of blood component delivery (median time: 323 s [118-668 s]; temperature variation: 4.5-8.9°C for pRBCs and FFP and 21.5-23.5°C for cryoprecipitate and platelet units). Furthermore, parameters of pRBC quality, including the haemolysis index and potassium and lactate dehydrogenase levels in plasma, were not significantly different before and after transportation through RLTS. Similarly, RLTS transportation affected neither the basic coagulation test results in FFP and cryoprecipitate specimens nor platelet aggregation and activation markers in apheresis platelet specimens.

CONCLUSION

Hospital-wide delivery of blood components via RLTS seems to be safe, reliable and cost-effective and does not have any negative impact on blood quality. Therefore, the establishment of standard criteria, protocols and guidelines based on further studies is needed.

Pseudohyperkalemia in chronic lymphocytic leukemia and diabetic ketoacidosis

Pseudohyperkalemia can lead to inaccurate hyperkalemia diagnosis, inappropriate initiation of potassium-lowering therapies, and overall unnecessary treatment possibly inducing iatrogenic hypokalemia. Patients with leukocytosis and thrombocytosis should raise clinical suspicion that hyperkalemic laboratory results in the absence of other traditional signs of hyperkalemia may be indicative of pseudohyperkalemia. Here we present a case of severe leukocytosis with chronic lymphocytic leukemia (CLL) found to have critically elevated potassium levels on admission to the intensive care unit (ICU). The patient was also diagnosed with diabetic ketoacidosis (DKA) at admission, requiring an increased frequency of electrolyte monitoring. The events leading to the prompt recognition of pseudohyperkalemia in this patient will be delineated alongside our recommendations for revising the institutional protocol to avoid false hyperkalemia diagnoses in patients with CLL.

Impact of blood collection devices and mode of transportation on peripheral venous blood gas parameters

BACKGROUND

Peripheral venous blood (PVB) gas analysis has become an alternative to arterial blood gas (BG) analysis in assessing acid-base balance. This study aimed to compare the effects of blood collection devices and modes of transportation on peripheral venous BG parameters.

METHODS

PVB-paired specimens were collected from 40 healthy volunteers into blood gas syringes (BGS) and blood collection tubes (BCT), transported by either a pneumatic tube system (PTS) or human courier (HC) to the clinical laboratory, and compared using a two-way ANOVA or Wilcoxon signed-rank test. To determine clinical significance, the PTS and HC-transported BGS and BCT biases were compared to the total allowable error (TEA).

RESULTS

PVB partial pressure of oxygen (pO2), fractional oxyhemoglobin (FO2Hb), fractional deoxyhemoglobin (FHHb), and oxygen saturation (sO2) showed statistically significant differences between BGS and BCT (p < 0.0001). Compared to HC-transported BGS and BCT, statistically significant increases in pO2, FO2Hb, sO2, oxygen content (only in BCT) (all p < 0.0001), and base excess extracellular (only in BCT; p < 0.0014) concentrations and a statistically significant decrease in FHHb concentration (p < 0.0001) were found in BGS and BCT delivered by PTS. The biases between PTS- and HC-transported BGS and BCT exceeded the TEA for many BG parameters.

CONCLUSIONS

Collecting PVB in BCT is unsuitable for pO2, sO2, FO2Hb, FHHb, and oxygen content determinations.

The impact of environmental factors on external and internal specimen transport

The environment that a clinical specimen is exposed to is an important preanalytical factor in laboratory testing. There are numerous environmental conditions that a specimen may experience before it arrives at the clinical laboratory for analysis. Specimens collected at offsite locations are typically stored at the site and transported to the clinical laboratory via courier. Depending on the geographic location, season, method of storage and method of transport, the specimen can experience varying climate conditions that can lead to inaccurate test results. Specimens collected within the healthcare institution are not exempt from suboptimal storage and transport environments. For example, specimens transported via pneumatic tube systems can experience extreme agitation and rapid accelerations and decelerations. Suboptimal storage and transport temperatures occur less frequently within health systems due to multiple regulatory requirements for temperature monitoring; however, temperature monitoring may not occur at every stage of the preanalytical phase. This review will highlight both internal and external environmental conditions that can cause preanalytical errors in clinical laboratory testing. Strategies to mitigate environmentally-induced preanalytical errors and regulatory gaps for environmental monitoring in the preanalytical phase will also be discussed.

Impact of Pneumatic Transport System on Preanalytical Phase Affecting Clinical Biochemistry Results

Introduction PTS (pneumatic transport system) is extensively being used in modern hospitals for rapid transportation of blood samples and other specimens. However, it has a potential impact on blood components, which should be investigated and nullified accordingly. This study was part of a correction program aimed at reducing hemolysis. It was done by comparing paired samples transported manually and by PTS.

Materials and Methods This study was initiated to monitor the impact of PTS on hemolysis of clinical biochemistry blood samples. It was performed in two phases—before and after the corrective action taken. Phase I: done after PTS installation but before the corrective action was taken. Duplicate samples from 100 healthy individuals were collected, one set transported by PTS and the other by human carriers. Both sets were assessed for 25 biochemistry analytes, hemolysis index (HI), and acceleration profiles using a data logger. Corrective measures were then taken, followed by phase II of the study. In phase II, the sample size and study design remained the same as phase I. All the test results of PTS and hand-carried samples were statistically analyzed for any significant difference.

Result In phase I, all the hemolysis-manifesting parameters, LDH (lactate dehydrogenase), potassium, AST (aspartate transaminase), and phosphorus, were raised in PTS samples as compared with the manual samples. Their differences were significant as the p-values were 0.001, 0.000, 0.025, and 0.047, respectively. The differences for LDH and potassium were clinically significant as well. HI (9%) and peak acceleration (15.7 g) were high in PTS samples.

In phase II, no statistically significant difference between paired samples was found for all biochemistry parameters except for a few which were clinically nonsignificant. For PTS samples, HI was 2.5% and the peak acceleration was 11.2 g, whereas for manual samples, HI was 2%.

Conclusion Evidence of hemolysis was found in PTS samples as compared with handheld samples, which was resolved after several corrective actions were taken. Thereafter, PTS became reliable for sample delivery in a routine biochemistry laboratory. Hence, each hospital should scrutinize their PTS for its effects on sample integrity to get rid of PTS-induced preanalytical errors.

Investigation of the effects of pneumatic tube transport system on routine biochemistry, hematology, and coagulation tests in Ankara City Hospital

OBJECTIVES

Academics are far from a consensus regarding the effects of pneumatic tube system (PTS) delivery on sample integrity and laboratory test results. As for the reasons for conflicting opinions, each PTS is uniquely designed, sample tubes and patient characteristics differ among studies. This study aims to validate the PTS utilized in Ankara City Hospital for routine chemistry, coagulation, and hematology tests by comparing samples delivered via PTS and porter.

METHODS

The study comprises 50 healthy volunteers. Blood samples were drawn into three biochemistry, two coagulation, and two hemogram tubes from each participant. Each of the duplicate samples was transferred to the emergency laboratory via Swiss log PTS (aka PTS-immediately) or by a porter. The last of the biochemistry tubes were delivered via the PTS, upon completion of coagulation of the blood (aka PTS-after). The results of the analysis in these groups were compared with multiple statistical analyses.

RESULTS

The study did not reveal any correlation between the PTS and serum hemolysis index. There were statistically significant differences in several biochemistry tests. However, none of them reached the clinical significance threshold. Basophil and large unidentified cell (LUC) tests had poor correlations (r=0.47 and r=0.60; respectively) and reached clinical significance threshold (the average percentages of bias, 10.2%, and 15.4%, respectively). The remainder of the hematology and coagulation parameters did not reach clinical significance level either.

CONCLUSIONS

The modern PTS validated in this study is safe for sample transportation for routine chemistry, coagulation, and hematology tests frequently requested in healthy individuals except for basophil and LUC.

Preanalytical quality improvement - an interdisciplinary journey, on behalf of the European Federation for Clinical Chemistry and Laboratory Medicine (EFLM) Working Group for Preanalytical Phase (WG-PRE)

Since the beginning of laboratory medicine, the main focus was to provide high quality analytics. Over time the importance of the extra-analytical phases and their contribution to the overall quality became evident. However, as the initial preanalytical processes take place outside of the laboratory and mostly without its supervision, all professions participating in these process steps, from test selection to sample collection and transport, need to engage accordingly. Focusing solely on intra-laboratory processes will not be sufficient to achieve the best possible preanalytical quality. The Working Group for the Preanalytical Phase (WG-PRE) of the European Federation of Clinical Chemistry and Laboratory Medicine (EFLM) has provided several recommendations, opinion papers and scientific evidence over the past years, aiming to standardize the preanalytical phase across Europe. One of its strategies to reach this goal are educational efforts. As such, the WG-PRE has organized five conferences in the past decade with the sole focus on preanalytical quality. This year's conference mainly aims to depict the views of different professions on preanalytical processes in order to acquire common ground as basis for further improvements. This article summarizes the content of this 6th preanalytical conference.

The incidence rate and influence factors of hemolysis, lipemia, icterus in fasting serum biochemistry specimens

Objective

Hemolysis, icterus, and lipemia (HIL) of blood samples have been a concern in hospitals because they reflect pre-analytical processes’ quality control. However, very few studies investigate the influence of patients’ gender, age, and department, as well as sample-related turnaround time, on the incidence rate of HIL in fasting serum biochemistry specimens.

Methods

A retrospective, descriptive study was conducted to investigate the incidence rate of HIL based on the HIL index in 501,612 fasting serum biochemistry specimens from January 2017 to May 2018 in a tertiary university hospital with 4,200 beds in Sichuan, southwest China. A subgroup analysis was conducted to evaluate the differences in the HIL incidence rate by gender, age and department of patients, and turnaround time of specimens.

Results

The incidence rate of hemolysis, lipemia and icterus was 384, 53, and 612 per 10,000 specimens. The male patients had a significantly elevated incidence of hemolysis (4.13% vs. 3.54%), lipemia (0.67% vs. 0.38%), and icterus (6.95% vs. 5.43%) than female patients. Hemolysis, lipemia, and icterus incidence rate were significantly associated with the male sex with an odds ratio (OR) of 1.174 [95% confidence interval (CI), 1.140–1.208], 1.757 (95%CI: 1.623–1.903), and 1.303 (95%CI: 1.273–1.333), respectively, (P<0.05). The hospitalized patients had a higher incidence of hemolysis (4.03% vs. 3.54%), lipemia (0.63% vs. 0.36%), and icterus (7.10% vs. 4.75%) than outpatients (P<0.001). Specimens with relatively longer transfer time and/or detection time had a higher HIL incidence (P<0.001). The Pediatrics had the highest incidence of hemolysis (16.2%) with an adjusted OR (AOR) of 4.93 (95%CI, 4.59–5.29, P<0.001). The Neonatology department had the highest icterus incidence (30.1%) with an AOR of 4.93 (95%CI: 4.59–5.29, P<0.001). The Neonatology department (2.32%) and Gastrointestinal Surgery (2.05%) had the highest lipemia incidence, with an AOR of 1.17 (95%CI: 0.91–1.51) and 4.76 (95%CI: 4.70–5.53), both P-value <0.001. There was an increasing tendency of hemolysis and icterus incidence for children under one year or adults aged more than 40.

Conclusion

Evaluation of HIL incidence rate and HIL-related influence factors in fasting serum biochemistry specimens are impartment to interpret the results more accurately and provide better clinical services to patients.

International Council for Standardization in Haematology (ICSH) recommendations for processing of blood samples for coagulation testing

This guidance document has been prepared on behalf of the International Council for Standardization in Haematology (ICSH). The aim of the document is to provide guidance and recommendations for the processing of citrated blood samples for coagulation tests in clinical laboratories in all regions of the world. The following areas are included in this document: Sample transport including use of pneumatic tubes systems; clots in citrated samples; centrifugation; primary tube storage and stability; interfering substances including haemolysis, icterus and lipaemia; secondary aliquots-transport, storage and processing; preanalytical variables for platelet function testing. The following areas are excluded from this document, but are included in an associated ICSH document addressing collection of samples for coagulation tests in clinical laboratories; ordering tests; sample collection tube and anticoagulant; preparation of the patient; sample collection device; venous stasis before sample collection; order of draw when different sample types are collected; sample labelling; blood-to-anticoagulant ratio (tube filling); influence of haematocrit. The recommendations are based on published data in peer-reviewed literature and expert opinion.

Pneumatic tube validation: Reducing the need for donor samples by integrating a vial-embedded data logger

BACKGROUND

The most common way to validate a pneumatic tube system is to compare pneumatic tube system-transported blood samples to blood samples carried by hand. The importance of measuring the forces inside the pneumatic tube system has also been emphasized. The aim of this study was to define a validation protocol using a mini data logger (VitalVial, Motryx Inc., Canada) to reduce the need for donor samples in pneumatic tube system validation.

METHODS

As an indicator of the total vibration, the blood samples are exposed to under pneumatic tube system transportation; the area under the curve was determined by a VitalVial for all hospital Tempus600 lines using a five-day validation protocol. Only the three lines with the highest area under the curves were clinically validated by analysing potassium, lactate dehydrogenase and aspartate aminotransferase. A month after pneumatic tube system commissioning, a follow-up on laboratory data was performed.

RESULTS

Mean area under the curve of the six lines ranged between 347 and 581. The variability of the area under the curve was between 1.51 and 11.55%. In the laboratory data follow-up, an increase in lactate dehydrogenase haemolysis was seen from the three lines with the highest area under the curve and the emergency department, which was not detected in the clinical validation. When the Tempus600 system was in commission, a higher mean area under the curve was measured.

CONCLUSION

A three-day validation protocol using VitalVials is enough to determine the stability of a Tempus600 system and can greatly reduce the need for donor samples. When in commission, the stability of the pneumatic tube system should be verified and lactate dehydrogenase haemolysis should be routinely checked.

Pneumatic tube transport of blood samples affects global hemostasis and platelet function assays

INTRODUCTION

Pneumatic tube systems (PTS) are frequently used for rapid and cost-effective transportation of blood samples to the clinical laboratory. The impact of PTS transport on platelet function measured by the Multiplate system and global hemostasis measured by the TEG 5000 was evaluated.

METHODS

Paired samples from healthy adult individuals were obtained at two study sites: Rigshospitalet (RH) and Nordsjaellands Hospital (NOH). One sample was transported by PTS and one manually (non-PTS). Platelet function was assessed by platelet aggregation (Multiplate) and global hemostasis was assessed by a variety of thrombelastography (TEG) assays. Multiplate (n = 39) and TEG (n = 32) analysis was performed at site RH, and Multiplate (n = 28) analysis was performed at site NOH.

RESULTS

A significant higher agonist-induced platelet aggregation was found for PTS samples compared to manual transport at site NOH (P < .02, all agonists). No significant difference was found at site RH (P > .05, all agonists). For Kaolin TEG, samples transported by PTS showed a significant lower R-time and higher Angle (P < .001). No significant differences in MA and LY30 was found (P > .05). ACT of RapidTEG was significantly reduced (P = .001) and MA of Functional Fibrinogen TEG was significantly increased (P < .001) after PTS transport. No significant impact of PTS was observed for TEG assays with heparinase (P > .05).

CONCLUSIONS

Depending on the type of PTS, transportation by PTS affected platelet aggregation measured by Multiplate. Furthermore, PTS alters TEG parameters possibly reflecting coagulation factors. Clinical laboratories should evaluate the effect of the local PTS on Multiplate and TEG results.

Pathologic Blood Samples Tolerate Exposure to Vibration and High Turbulence in Simulated Drone Flights, but Plasma Samples Should be Centrifuged After Flight

Objective. Most of the previous studies of drone transport of blood samples examined normal blood samples transported under tranquil air conditions. We studied the effects of 1- and 2-hour drone flights using random vibration and turbulence simulation (10-30 g-force) on blood samples from 16 healthy volunteers and 74 patients with varying diseased. Methods: Thirty-two of the most common analytes were tested. For biochemical analytes, we used plasma collected in lithium heparin tubes with and without separator gel. Gel samples were analyzed for the effect of separation by centrifugation before or after turbulence. Turbulence was simulated in an LDS V8900 high-force shaker using random vibration (range, 5–200 Hz), with samples randomly allocated to 1- or 2-hour flights with 25 or 50 episodes of turbulence from 10 to 30 G. Results: For all hematologic and most biochemical analytes, test results before and after turbulence exposure were similar (bias < 12%, intercepts < 10%). However, aspartate aminotransferase, folate, lactate dehydrogenase and lipid index increased significantly in samples separated by gel and centrifugation prior to vibration and turbulence test. These changes increased form 10 G to 30 G, but were not observed when the samples were separated after vibration and turbulence. Conclusions: Whole blood showed little vulnerability to turbulence, whereas plasma samples separated from blood cells by gel may be significantly influenced by turbulence when separated by spinning before the exposure. Centrifugation of plasma samples collected in tubes with separator gel should be avoided before drone flights that could be subject to turbulence.

Age and sex dependent reference intervals for random plasma/serum glucose concentrations related to different sampling devices and determined by an indirect procedure with data mining

The glucose concentration in plasma or serum is one of the most often requested analytical values in laboratory medicine. Whereas the analytical part of the glucose determination is well standardised, the standardisation of the pre-examination part (pre-analytical phase) is not sufficiently solved, yet. In view of the present controversial discussion regarding the most efficient prevention of pre-analytical glycolysis, the question arises whether the economical and logistic expenses for inhibiting glycolysis determining random glucose concentration are justified. In hospitals with adequate logistics (e.g. pneumatic tube systems for blood tubes) to guarantee a blood sample transport time of about 1 – 2 h, plasma or serum without prevention of glycolysis can be applied for random glucose concentrations if the reference limits are estimated by the laboratory. If such logistics are not available, especially in primary care services, either plasma or serum samples or whole blood in special tubes with anti-glycolytic additives may be sent to the laboratory.

A Comparison of Four 3-Axis-Accelerometers for Monitoring Hospital Pneumatic Tube Systems

BACKGROUND

Validation of hospital pneumatic tube systems (PTS) is recommended to predict and prevent errors caused by sample hemolysis. 3-Axis accelerometer dataloggers have been successfully implemented as tools for PTS validation, but the most suitable device for such validation has not been investigated. The aim of this study was to evaluate the performance of four commercially available 3-axis accelerometers for PTS validation.

METHODS

PCE-VD3 (PCE), CEM DT-178A (CEM), Extech VB300 (EXT), and MSR 145 (MSR) dataloggers were placed into a single PTS carrier and repeatedly transported through one of three PTS routes. The number and magnitude of accelerations within each PTS route was collected by each device. Deming regression analysis was used to compare device performance.

RESULTS

The MSR datalogger captured the greatest number of g-forces >3 g, 5 g, 10 g, and 15 g, and the greatest magnitude of g-force (26.7 g) relative to the other devices (CEM: 23.0 g, EXT: 23.3 g, PCE: 23.7 g). As a result of increased sampling frequency, the MSR recorded the lowest AUC and the greatest number of g-forces exceeding 3 g relative to the other devices. Subjectively, the data were difficult to extract from 4 tested devices.

CONCLUSIONS

Commercially available dataloggers differ in their ability to detect the number and magnitude of g-forces within PTSs. We recommend that one device be used to perform all PTS evaluations, with baseline evaluations for tolerable AUC, number, and magnitude of g-forces established internally. Lack of harmonization, cumbersome data processing, and time-consuming data analysis are substantial barriers to universal implementation of dataloggers for PTS validation and monitoring.

A Comparative Study of Blood Sampling From Venipuncture and Short Peripheral Catheters in Pediatric Inpatients

This prospective, comparative study examined blood test results, hemolysis rates, and patient perceptions related to 2 blood sampling methods in pediatric inpatients (N = 95). Blood specimens were drawn via venipuncture and a short peripheral catheter used for fluid administration. Results revealed no significant differences in potassium and glucose levels. No clinically significant difference in hemoglobin was noted. Hemolysis rates were 4% for venipuncture samples and 15% when drawn from peripheral catheters. One catheter became occluded after a blood draw. Patients/parents rated distress and dissatisfaction with venipuncture as significantly greater compared with short peripheral catheter blood sampling (P < .001).

Automation in biobanking from a laboratory medicine perspective

Biobanks are important infrastructures to support clinical research and developments in personalized medicine. Although biobanking is not a new invention it has gained importance in the last few years due to increased quality requirements for biological samples in biomedical research and new high resolution Omics-technologies. Moreover, quality-assured collection, processing and storage of biological samples with defined pre-analytical history plays a key role for reproducibility in scientific research and paves the path towards precision medicine. Due to the increasing need for large numbers of samples, both in basic as well as in translational research, particular attention must be paid to sample acquisition and preparation in order to guarantee the highest possible sample quality. This can be achieved by following best practices or implementation and operation of specific biobank quality management systems that are compliant with the new DIN EN ISO 20387. Moreover, automation of critical process steps in biobanking can help to reach the highest quality standard and consistent sample quality. The following article will present and discuss currently available solutions for process automation in biobanking.

Use of clinical data and acceleration profiles to validate pneumatic transportation systems

Background

Modern pneumatic transportation systems (PTSs) are widely used in hospitals for rapid blood sample transportation. The use of PTS may affect sample integrity. Impact on sample integrity in relation to hemolysis and platelet assays was investigated and also, we wish to outline a process-based and outcome-based validation model for this preanalytical component.

Methods

The effect of PTS was evaluated by drawing duplicate blood samples from healthy volunteers, one sent by PTS and the other transported manually to the core laboratory. Markers of hemolysis (potassium, lactate dehydrogenase [LD] and hemolysis index [HI]) and platelet function and activation were assessed. Historic laboratory test results of hemolysis markers measured before and after implementation of PTS were compared. Furthermore, acceleration profiles during PTS and manual transportation were obtained from a mini g logger in a sample tube.

Results

Hand-carried samples experienced a maximum peak acceleration of 5 g, while peaks at almost 15 g were observed for PTS. No differences were detected in results of potassium, LD, platelet function and activation between PTS and manual transport. Using past laboratory data, differences in potassium and LD significantly differed before and after PTS installation for all three lines evaluated. However, these estimated differences were not clinically significant.

Conclusions

In this study, we found no evidence of PTS-induced hemolysis or impact on platelet function or activation assays. Further, we did not find any clinically significant changes indicating an acceleration-dependent impact on blood sample quality. Quality assurance of PTS can be performed by surveilling outcome markers such as HI, potassium and LD.

Hemolyzed Specimens: Major Challenge for Identifying and Rejecting Specimens in Clinical Laboratories

Pre-analytical quality in clinical chemistry testing is as important as analytical and post-analytical quality. The most prevalent pre-analytical interference and a major source of error producing unreliable laboratory test results is hemolysis of blood samples. In vitro hemolysis may be due to the blood withdrawal technique or sample handling whereas in vivo hemolysis can originate from acquired, hereditary, or iatrogenic conditions and is not technique dependent. Interpreting in vivo or in vitro hemolysis requires clinicians to supply reliable clinical history and findings. Even then, to reject or release the result with interpretation is still under debate. Thus, hemolyzed specimens are a serious pre-analytical problem calling for well-designed and strictly implemented laboratory guidelines. The aim of this non-systematic review (addressed to healthcare professionals) was to highlight the challenges in identifying and rejecting hemolysis specimens.

Parameters for Validating a Hospital Pneumatic Tube System

BACKGROUND

Pneumatic tube systems (PTSs) provide rapid transport of patient blood samples, but physical stress of PTS transport can damage blood cells and alter test results. Despite this knowledge, there is limited information on how to validate a hospital PTS.

METHODS

We compared 2 accelerometers and evaluated multiple PTS routes. Variabilities in PTS forces over the same routes were assessed. Response curves that demonstrate the relationship between the number and magnitude of accelerations on plasma lactate dehydrogenase (LD), hemolysis index, and potassium in PTS-transported blood from volunteers were generated. Extrapolations from these relationships were used to predict PTS routes that may be prone to false laboratory results. Historical data and prospective patient studies were compared with predicted effects.

RESULTS

The maximum recorded g-force was 10g for the smartphone and 22g for the data logger. There was considerable day-to-day variation in the magnitude of accelerations (CV, 4%-39%) within a single route. The linear relationship between LD and accelerations within the PTS revealed 2 PTS routes predicted to increase LD by ≥20%. The predicted increase in LD was similar to that observed in patient results when using that PTS route.

CONCLUSIONS

Hospital PTSs can be validated by documenting the relationship between the concentrations of analytes in plasma, such as LD, with PTS forces recorded by 3-axis accelerometers. Implementation of this method for PTS validation is relatively inexpensive, simple, and robust.

Effect of Pneumatic Tubing System Transport on Platelet Apheresis Units

Platelet apheresis units are transfused into patients to mitigate or prevent bleeding. In a hospital, platelet apheresis units are transported from the transfusion service to the healthcare teams via two methods: a pneumatic tubing system (PTS) or ambulatory transport. Whether PTS transport affects the activity and utility of platelet apheresis units is unclear. We quantified the gravitational forces and transport time associated with PTS and ambulatory transport within our hospital. Washed platelets and supernatants were prepared from platelet apheresis units prior to transport as well as following ambulatory or PTS transport. For each group, we compared resting and agonist-induced platelet activity and platelet aggregate formation on collagen or von Willebrand factor (VWF) under shear, platelet VWF-receptor expression and VWF multimer levels. Subjection of platelet apheresis units to rapid acceleration/deceleration forces during PTS transport did not pre-activate platelets or their ability to activate in response to platelet agonists as compared to ambulatory transport. Platelets within platelet apheresis units transported via PTS retained their ability to adhere to surfaces of VWF and collagen under shear, although platelet aggregation on collagen and VWF was diminished as compared to ambulatory transport. VWF multimer levels and platelet GPIb receptor expression was unaffected by PTS transport as compared to ambulatory transport. Subjection of platelet apheresis units to PTS transport did not significantly affect the baseline or agonist-induced levels of platelet activation as compared to ambulatory transport. Our case study suggests that PTS transport may not significantly affect the hemostatic potential of platelets within platelet apheresis units.

The Effects of Sample Transport by Pneumatic Tube System on Routine Hematology and Coagulation Tests

Background

Automation helps improve laboratory operational efficiency and reduce the turnaround time. Pneumatic tube systems (PTS) automate specimen transport between the lab and other areas of the hospital. Its effect on complete blood count (CBC) and coagulation is still controversial.

Aim

To study the effects of pneumatic tube system sample transport on complete blood count and coagulation parameters to compare them with hand delivered samples.

Methods

75 paired samples for complete blood count and 25 paired samples for coagulation analysis were compared between samples sent via pneumatic tube system and hand delivered system.

Results

PTS showed significant decrease in red cell indices such as MCV and RDW and increase in MCHC. Other red cell parameters and WBC parameters showed no statistical significant difference. Statistically significant increase in platelet count was observed with PTS samples. However, these differences were clinically insignificant. No significant effect of PTS was found in PT and APTT samples compared to the hand delivered samples.

Conclusion

Despite statistically significant changes in RBC parameters such as MCV, RDW, and MCHC and platelet count, these changes were clinically insignificant. Hence, blood samples for CBC and coagulation assay can safely be transported via our hospital's PTS. However, further studies on platelet count are warranted to ensure safe transport and accuracy of the results.

Blood Sample Transportation by Pneumatic Transportation Systems: A Systematic Literature Review

BACKGROUND

Pneumatic transportation systems (PTSs) are increasingly used for transportation of blood samples to the core laboratory. Many studies have investigated the impact of these systems on different types of analyses, but to elucidate whether PTSs in general are safe for transportation of blood samples, existing literature on the subject was systematically assessed.

METHODS

A systematic literature review was conducted following the preferred reporting items for systematic reviews and metaanalyses (PRISMA) Statement guidelines to gather studies investigating the impact of PTS on analyses in blood samples. Studies were extracted from PubMed and Embase. The search period ended November 2016.

RESULTS

A total of 39 studies were retrieved. Of these, only 12 studies were conducted on inpatients, mainly intensive care unit patients. Blood gases, hematology, and clinical chemistry were well investigated, whereas coagulation, rotational thromboelastometry, and platelet function in acutely ill patients were addressed by only 1 study each. Only a few parameters were affected in a clinically significant way (clotting time parameter in extrinsic system thromboelastometry, pO2 in blood gas, multiplate analysis, and the hemolysis index).

CONCLUSIONS

Owing to their high degree of heterogeneity, the retrieved studies were unable to supply evidence for the safety of using PTSs for blood sample transportation. In consequence, laboratories need to measure and document the actual acceleration forces in their existing PTS, instituting quality target thresholds for these measurements such as acceleration vector sums. Computer modeling might be applied to the evaluation of future PTS installations. With the increasing use of PTS, a harmonized, international recommendation on this topic is warranted.

WITHDRAWN: Relocation of blood gas laboratory to the emergency department helps decrease lactic acid values

The Publisher regrets that this article is an accidental duplication of an article that has already been published, http://dx.doi.org/10.1016/j.ajem.2018.03.017. The duplicate article has therefore been withdrawn. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.

Relocation of blood gas laboratory to the emergency department helps decrease lactic acid values

IMPORTANCE

Emergency Physicians often rely on Lactic Acid (LA) values to make important clinical decisions. Accuracy of LA values improve when blood gas analysis is performed in the emergency department (ED) as opposed to a satellite laboratory (SL).

OBJECTIVE

To investigate an association between blood gas laboratory location and accuracy of ED lactic acid samples.

METHODS

The study team evaluated lactic acid values from venous and arterial blood gas samples drawn between June 1, 2015 and September 30, 2016. The study was exempt from institutional review board approval. Samples were separated into two groups: those which were drawn prior to and after relocation of the blood gas laboratory to the ED. The data, including patient demographic characteristics, acute illness severity indices, and blood gas results were compared within and between each group using t-test for continuous variables and chi-square test for categorical variables. The primary outcome was the mean lactate value measured in the SL group in 2015 compared to the ED group in 2016. Potassium and creatinine values were measured between the two groups as secondary outcomes.

RESULTS

Of the 21,595 consecutive samples drawn, 10,363 samples were from the SL group and 11,232 from the ED group. The SL group included 5458 (52.7%) women; mean (SD) age was 61.8 (21.0). The ED group contained 5860 (52.2%) women; mean (SD) age was 61.7 (20.5). Mean Emergency Severity Index (ESI) were the same in each group at 2.31 and rates of Systemic Inflammatory Response Syndrome (SIRS) were also equivalent in each group at 22.2%. Significant differences were found between LA values in the SL group (mean 2.21mmol/L) and in the ED group (mean 1.99mmol/L) with a p value of <0.0001. There was a small statistical significance between the difference in potassium values in the SL group (mean 3.98meq/L) compared to the ED Group (mean 3.96meq/L) with a p value of 0.022. No significant difference was found between the creatinine values.

CONCLUSIONS AND RELEVANCE

These results suggest that mean lactate values decreased when measured in an ED blood gas laboratory and may provide more accurate LA results than blood gas samples analyzed at an SL blood gas laboratory within the same institution. Hospitals may consider moving blood gas laboratories to the ED to improve accuracy of one of the most important early blood markers used in the definition of sepsis and in the identification of the critically ill.

Comparison of pneumatic tube system with manual transport for routine chemistry, hematology, coagulation and blood gas tests

BACKGROUND

The pneumatic tube system (PTS) is commonly used in modern clinical laboratories to provide quick specimen delivery. However, its impact on sample integrity and laboratory testing results are still debatable. In addition, each PTS installation and configuration is unique to its institution. We sought to validate our Swisslog PTS by comparing routine chemistry, hematology, coagulation and blood gas test results and sample integrity indices between duplicate samples transported either manually or by PTS.

METHODS

Duplicate samples were delivered to the core laboratory manually by human courier or via the Swisslog PTS. Head-to-head comparisons of 48 routine chemistry, hematology, coagulation and blood gas laboratory tests, and three sample integrity indices were conducted on 41 healthy volunteers and 61 adult patients.

RESULTS

The PTS showed no impact on sample hemolysis, lipemia, or icterus indices (all p<0.05). Although alkaline phosphatase, total bilirubin and hemoglobin reached statistical significance (p=0.009, 0.027 and 0.012, respectively), all had very low average bias which ranged from 0.01% to 2%. Potassium, total hemoglobin and percent deoxyhemoglobin were statistically significant for the neonatal capillary tube study (p=0.011, 0.033 and 0.041, respectively) but no biases greater than ±4% were identified for these parameters. All observed differences of these 48 laboratory tests were not clinically significant.

CONCLUSIONS

The modern PTS investigated in this study is acceptable for reliable sample delivery for routine chemistry, hematology, coagulation and blood gas (in syringe and capillary tube) laboratory tests.

Effects of one directional pneumatic tube system on routine hematology and chemistry parameters; A validation study at a tertiary care hospital

Background

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.

Methods

Paired EDTA and SST blood samples were collected from 56 randomly selected patients. Laboratory parameters were compared between PTS group and hand-delivered group.

Results

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.

Conclusions

All laboratories should validate the stability of the results from samples according to transportation method.

The impact of pneumatic tube system on routine laboratory parameters: a systematic review and meta-analysis

Background:

Pneumatic tube system (PTS) is a widely used method of transporting blood samples in hospitals. The aim of this study was to evaluate the effects of the PTS transport in certain routine laboratory parameters as it has been implicated with hemolysis.

Methods:

A systematic review and a meta-analysis were conducted. PubMed and Scopus databases were searched (up until November 2016) to identify prospective studies evaluating the impact of PTS transport in hematological, biochemical and coagulation measurements. The random-effects model was used in the meta-analysis utilizing the mean difference (MD). Heterogeneity was quantitatively assessed using the Cohran’s

Results:

From a total of 282 studies identified by the searching procedure, 24 were finally included in the meta-analysis. The meta-analysis yielded statistically significant results for potassium (K) [MD=0.04 mmol/L; 95% confidence interval (CI)=0.015–0.065; p=0.002], lactate dehydrogenase (LDH) (MD=10.343 U/L; 95% CI=6.132–14.554; p<10

Conclusions:

This meta-analysis suggests that PTS may be associated with alterations in K, LDH and AST measurements. Although these findings may not have any significant clinical effect on laboratory results, it is wise that each hospital validates their PTS.

Extending laboratory automation to the wards: effect of an innovative pneumatic tube system on diagnostic samples and transport time

Background:

The innovative pneumatic tube system (iPTS) transports one sample at a time without the use of cartridges and allows rapid sending of samples directly into the bulk loader of a laboratory automation system (LAS). We investigated effects of the iPTS on samples and turn-around time (TAT).

Methods:

During transport, a mini data logger recorded the accelerations in three dimensions and reported them in arbitrary area under the curve (AUC) units. In addition representative quantities of clinical chemistry, hematology and coagulation were measured and compared in 20 blood sample pairs transported by iPTS and courier.

Results:

Samples transported by iPTS were brought to the laboratory (300 m) within 30 s without adverse effects on the samples. The information retrieved from the data logger showed a median AUC of 7 and 310 arbitrary units for courier and iPTS transport, respectively. This is considerably below the reported limit for noticeable hemolysis of 500 arbitrary units.

Conclusions:

iPTS reduces TAT by reducing the hands-on time and a fast transport. No differences in the measurement results were found for any of the investigated 36 analytes between courier and iPTS transport. Based on these findings the iPTS was cleared for clinical use in our hospital.

Neonatal Intensive Care Unit Quality Initiative: Identifying Preanalytical Variables Contributing to Specimen Hemolysis and Measuring the Impact of Evidence-Based Practice Interventions

OBJECTIVES

Blood specimen hemolysis is a major cause of sample recollection in the neonatal intensive care unit. We aimed to reduce the hemolysis rate from 6.3% at baseline to less than 4% within the 9 months' duration of the study.

METHODS

Intravenous infusion of lipid emulsion during sample collection, sample collection site, and blood sample transportation methods were investigated as possible contributors to hemolysis. Subsequently, two practice improvements were implemented: pausing lipid emulsion infusion prior to collection and slowing withdrawal rates through arterial catheters.

RESULTS

Samples were more likely to be hemolyzed if they were collected during lipid infusion and subsequently transported by pneumatic tube or collected through an arterial catheter. Retrospective analysis demonstrated a decreased number of tests cancelled due to specimen hemolysis (3.5%) after our interventions.

CONCLUSIONS

We identified three variables contributing to hemolysis and instituted two clinical practice interventions to significantly reduce test cancellations due to hemolysis.

Stability of Routine Biochemical Analytes in Whole Blood and Plasma From Lithium Heparin Gel Tubes During 6-hr Storage

BACKGROUND

The stability of biochemical analytes has already been investigated, but results strongly differ depending on parameters, methodologies, and sample storage times. We investigated the stability for many biochemical parameters after different storage times of both whole blood and plasma, in order to define acceptable pre- and postcentrifugation delays in hospital laboratories.

METHODS

Twenty-four analytes were measured (Modular® Roche analyzer) in plasma obtained from blood collected into lithium heparin gel tubes, after 2-6 hr of storage at room temperature either before (n = 28: stability in whole blood) or after (n = 21: stability in plasma) centrifugation. Variations in concentrations were expressed as mean bias from baseline, using the analytical change limit (ACL%) or the reference change value (RCV%) as acceptance limit.

RESULTS

In tubes stored before centrifugation, mean plasma concentrations significantly decreased after 3 hr for phosphorus (-6.1% [95% CI: -7.4 to -4.7%]; ACL 4.62%) and lactate dehydrogenase (LDH; -5.7% [95% CI: -7.4 to -4.1%]; ACL 5.17%), and slightly decreased after 6 hr for potassium (-2.9% [95% CI: -5.3 to -0.5%]; ACL 4.13%). In plasma stored after centrifugation, mean concentrations decreased after 6 hr for bicarbonates (-19.7% [95% CI: -22.9 to -16.5%]; ACL 15.4%), and moderately increased after 4 hr for LDH (+6.0% [95% CI: +4.3 to +7.6%]; ACL 5.17%). Based on RCV, all the analytes can be considered stable up to 6 hr, whether before or after centrifugation.

CONCLUSION

This study proposes acceptable delays for most biochemical tests on lithium heparin gel tubes arriving at the laboratory or needing to be reanalyzed.

Heparinate but not serum tubes are susceptible to hemolysis by pneumatic tube transportation

Background:

Pneumatic tube transportation (PTT) may induce hemolysis (H) in blood samples. We aimed to compare the H degree before and after PTT implementation in our hospital.

Methods:

Hemolysis indices (HI) for all lithium-heparin plasma samples (P) drawn by the Emergency Department in 2-month periods were retrospectively collected and pre- (n=3579) and post-PTT (n=3469) results compared. The impact of PTT introduction was investigated on LDH [HI threshold (HIt), 25], conjugated bilirubin (cBIL) (HIt, 30), K (HIt, 100) and ALT (HIt, 125). In addition, HI retrieved for P and paired serum samples collected in silica clot activator tubes (S) from the same venipuncture were compared in pre- (n=501) and post-PTT (n=509) periods.

Results:

Median (5–95th percentile) HI in P was significantly higher in post-PTT period [7 (0–112) vs. 6 (0–82), p<0.001]. Results reported as ‘Hemolysis’ in P increased from 6.6% in pre-PTT to 9.4% in post-PTT (p<0.001). Investigated tests gave the following rejection rates (pre-PTT vs. post-PTT): LDH, 13.4% vs. 18.8%, p<0.001; cBIL, 9.4% vs. 27.0%, p<0.05; K, 3.7% vs. 5.6%, p<0.001; ALT, 2.9% vs. 4.4%, p<0.01. The slightly higher susceptibility to H of S compared to paired P found in the pre-PTT [9 (1–64) vs. 6 (0–85)] was not confirmed in the post-PTT period [7 (0–90) vs. 8 (1–72)], in which median HI in S was significantly lower (p<0.001) than in pre-PTT.

Conclusions:

In our setting PTT promotes H in P, increasing the rate of rejected tests. The use of S appears to protect against the hemolysing effect of PTT.

Preanalytical considerations in blood gas analysis

Blood gas testing is a commonly ordered test in hospital settings, where the results almost always have the potential to dictate an immediate or urgent response. The preanalytical steps in testing, from choosing the correct tests to ensuring the specimen is introduced into the instrument correctly, must be perfectly coordinated to ensure that the patient receives appropriate and timely therapy in response to the analytical results. While many of the preanalytical steps in blood gas testing are common to all laboratory tests, such as accurate specimen labeling, some are unique to this testing because of the physicochemical properties of the analytes being measured. The common sources of preanalytical variation in blood gas testing are reviewed here.

Random variation and systematic error caused by various preanalytical variables, estimated by linear mixed-effects models

BACKGROUND

We wanted to determine whether specific, preanalytical sample handling increases preanalytical variation and bias test results compared with optimal handling.

METHODS

Blood was collected into 4 serum-separation tubes from each arm of 60 outpatients. In 30 of the patients, half of the tubes were transported in the pneumatic tube system, while the other half were manually delivered. In the remaining patients, the blood samples were collected using 21-gauge straight needles (green needles) and 23-gauge butterfly needles. Half of the tubes were mixed by inverting 5-6 times, and the other half by one inversion. Linear mixed-effects models were used as statistical method.

RESULTS

Transporting samples in the pneumatic tube system caused a significant bias to the results for LD (4.5 U/L, p<0.001) and magnesium (0.0021 mmol/L, p=0.003). For CK and glucose, the preanalytical variation was significantly higher for samples transported in the pneumatic tube system vs manual delivery. Using butterfly needles resulted in lower values (p<0.05) for calcium (-0.0072 mmol/L), CK (-0.75 U/L) and LD (-1.6 U/L) compared with 21-gauge needles. The preanalytical variation for ALP was significantly higher with butterfly needles.

CONCLUSIONS

The specific sample handling had significant but small random and systematic effects on results for some analytes.