Pneumatic Tube Research Articles (Page 1)

Abstract Objectives Transporting blood samples with pneumatic tube systems (PTSs) is routine in many hospitals. The influence of PTS transport on cell-free DNA (cfDNA) and circulating tumor DNA (ctDNA) analyses has not been comprehensively tested. Methods Paired blood samples from non-patient donors and cancer patients were transported manually or by PTS at two Danish hospitals using different PTS. A g-logger evaluated the forces applied to samples in each transport method. The concentration of short and long cfDNA fragments and ctDNA markers was analyzed using droplet digital PCR (ddPCR) and compared according to transportation. Different blood collection tubes (BCTs) were also investigated. Results All transportation methods subject samples to significantly different forces. The cfDNA concentration was slightly higher in samples transported with the Sumetzberger PTS than manually. There were no differences in cfDNA, whether using EDTA or Roche BCTs transported using Tempus600 or manually. Colorectal cancer patient samples showed insignificant changes in ratio of fragment lengths when transported by PTS compared to manual transport. In metastatic cancer patients, only a minor change in long/short fragment ratio was observed in PTS-transported samples. No discrepancy in ctDNA concentration/fraction was observed in cancer patient samples. Higher yields of cfDNA were obtained from EDTA samples, but no other differences were observed among the tested BCTs. Conclusions Although PTS transport introduced minor variations in cfDNA concentrations, these did not impact ctDNA interpretation. However, as PTSs vary in design, their pre-analytical effects should be carefully assessed, particularly as ctDNA analysis becomes more widely implemented in clinical practice.

Abstract Background Our laboratory was asked to perform Viscoelastic testing on the Rotem Sigma (Point of Care) (Werfen, Munich, Germany), currently performed by the Anesthesia Department on the Rotem Delta (Benchtop) analyzer to support liver transplantation surgery. This testing, performed on citrated whole blood, supports transfusion management and optimization of hemostasis. The semi-quantitative assays performed on each test cartridge consist of INTEM C (to monitor coagulation via the intrinsic pathway), EXTEM C (to monitor coagulation via the extrinsic pathway), FIBTEM C (to monitor coagulation via the extrinsic pathway, assessing fibrinogen status and fibrin polymerization by blocking platelet contribution to clot firmness), and HEPTEM C (to monitor coagulation via the intrinsic pathway, after inactivating heparin). Each assay provides several parameters including Clotting Time (CT), Amplitude (up to 20 minutes after clotting time), Maximum Clot Formation (MCF), and Lysis Index after 60 minutes (LI60). We also evaluated the impact on specimens during transportation through the pneumatic tube. Methods Precision studies were performed using Quality Control materials ROTROL N and P (Werfen, Munich, Germany). Comparison studies were performed on citrated whole blood against the Rotem Delta (Werfen, Munich, Germany), and between citrated whole blood samples that were carried by hand versus being sent to the lab by pneumatic tube. Results Precision studies for Rotem Sigma (n=38) for ROTROL N and P, respectively, were: EXTEM C-(Amplitude, shown as a range) 5.6%-6.8% and 3.2-4.2%; EXTEM C-CT 9.2% and 5.4%; FIBTEM C-(Amplitude, shown as a range) 4.4%-5.1% and 5.1%-6.7%; HEPTEM C-(Amplitude, shown as a range) 5.7%-7.4% and 4.3%-8.3%; HEPTEM C-CT 9.5% and 6.6%; INTEM C-(Amplitude, shown as a range) 2.0-2.4% and 2.9%- 3.2%; INTEM C-CT 4.2% and 3.3. Method Comparison results were EXTEM C-(Amplitude, shown as a range) R=0.7607-0.7667; EXTEM C-CT R=0.7090; EXTEM C-MCF R=0.7026; FIBTEM C-(Amplitude, shown as a range) R=0.9160-0.9290; FIBTEM C-MCF R=0.9265; HEPTEM C-(Amplitude, shown as a range) R=0.8525-0.8751; HEPTEM C-CT R=0.7719; HEPTEM C-MCF R=0.8343 (Table 1). Comparison of hand-carried specimens to those sent by pneumatic tube demonstrated a maximum difference of <|8.0|% for all assays and parameters. Conclusion The Rotem Sigma showed good precision and acceptable correlation to the Rotem Delta and is considered acceptable for testing patient samples. In addition, the pneumatic tube has been shown to be an acceptable means of transportation for samples intended to be tested on the Rotem Sigma.

Abstract Background The Oncology Department at our institution requested faster turn-around times (TAT) for chemistry testing. Prior to their request, serum separator tubes (SST) were collected and tested in our core laboratory. To accommodate the request, we added plasma total bilirubin and aspartate aminotransferase (AST) to our stat laboratory test menu with collection in plasma separator tubes (PST). Upon implementation of this testing change, we observed an increase in specimen recollection rates due to hemolysis. We systematically evaluated laboratory testing variables that could have contributed to the increase: pneumatic tube transport path, differences in hemolysis measurements between chemistry analyzer models, and specimen types. Previous studies have demonstrated that lithium heparin plasma specimens are more susceptible to hemolysis than serum. Likewise, patients undergoing chemotherapy or radiation therapy may have fragile red blood cell (RBC) membranes, further complicating the issue. Our study*s objective was to assess the impact of changing from SST to PST collections. We conducted a 3-month pilot study to determine if we could reduce our recollection rates by collecting/testing Rapid Serum Tube (RST), while maintaining plasma TAT. Methods We compared recollection rates for specimens collected from the oncology patients and tested in our core laboratory (SST, May-June 2021), stat laboratory (PST, September-November 2022), pilot period in stat lab (RST, January-March 2023), and post-pilot period in stat lab (PST, May-July 2023). Data were extracted from our laboratory information system and recollection rates were calculated using Tableau (Salesforce, Inc, San Francisco, CA). Analysis was performed in Excel (Microsoft, Redmond, WA) using Student’s t-test, with p < 0.05 defined as statistically significant. Results SST specimens collected from oncology patients and tested in the core lab (May-June 2021) resulted in a recollection rate of 0.17% (4/2341). PST specimens sent to the stat lab (Sept-Nov 2022) had an increased recollection rate of 0.90% (55/6129, p-value < 0.001). During the pilot period when RST tubes were used (Jan-Mar 2023), our recollection rate decreased to 0.19% (11/5801, p-value 0.014). After the pilot period ended and PST tubes were again utilized for testing (May-July 2023), the recollection rate again increased to 0.34% (22/6500, p-value 0.019). Conclusion Rapid TAT of laboratory results within specialized-care settings, such as a cancer treatment clinic, is necessary to provide patients with the most effective and personalized treatment regimens. Hemolysis presents a challenge as it generates an analytical issue with the release of contents from RBCs that may spuriously affect the concentration of the analyte being measured, delaying result reporting due to the need for specimen recollection. The data from our study highlight the utility of rapid serum tubes. Not only did they achieve stat TAT that was observed with the use of PST, but they also decreased specimen recollection rates that mirror the low rates observed with the use of SST. Thus, this technology may be an excellent replacement for standard SST when specimen integrity is critical to rapidly reporting accurate test results.

Abstract Background Ethylene glycol (EG) is a toxic alcohol in products such as antifreeze. Its sweet taste often leads to accidental or intentional ingestion, particularly among individuals with alcohol addiction. EG poisoning affects multiple organ systems and can result in metabolic acidosis, ataxia, and even death. Recently, there has been growing clinical interest in an enzymatic automated assay, driven by cautious consideration due to the limited knowledge of its performance compared to chromatographic methods. Moreover, there is limited data about EG stability in biological samples under different pre-analytical conditions. This study aims to investigate the impact of various factors, including collection tube type, handling methods, and time, on the stability of ethylene glycol in blood and serum samples. Additionally, it seeks to compare the performance of an automated enzymatic assay with gas chromatography-mass spectrometry (GC-MS). Methods This multi-part study was conducted at the University of Kentucky emergency department laboratory. These studies used six types of vacuum blood collection tubes with varying additives or gel separators. Samples were spiked with low (30 mg/dL) and mid (300 mg/dL) EG concentrations. Four experimental setups were employed: (1) Vacuum Tube Validation to compare tube types, (2) a 24-hour Stability Study with timed intervals of analysis, (3) an Unspun Study examining samples left uncentrifuged for up to four hours, and (4) a comparison between manual and pneumatic tube system (PTS) delivery methods. Assays were conducted using the Catachem enzymatic kit on the Cobas 6000 501c analyzer, and results were cross-verified with GC-MS. Over an 18-month period, we also monitored the in-house application. We verified all samples with concentrations between 5–24 mg/dL or those showing interference, as indicated by the kinetic curve, using GC-MS. Results EG stability was generally maintained across all conditions tested. In the 24-hour stability study, percent recovery differences spanned 0.5–19.6%, falling within the acceptable Total Error Allowable (TEa) of 25%. Light green and gold-top tubes demonstrated lower variability in the unspun study, with coefficients of variation (CV) under 2%. Comparisons between manual and PTS delivery yielded minimal variability (<2%) in analyte recovery, indicating negligible effects of the handling method. Notably, variability was more pronounced in low-concentration samples compared to mid-concentration samples, particularly in tubes with sodium heparin or EDTA additives. Out of 356 samples tested for EG using the enzymatic method, only 26 were positive. Among these, only two samples had concentrations above 10 mg/dL; these were the only samples that also tested positive by GC-MS. Conclusion This study establishes robust evidence for the stability of EG in blood and serum under varying conditions, providing crucial insights for clinical and forensic toxicology. It demonstrated that EG does not adhere to the gel layer in serum and plasma gel separator tubes. The findings validate the enzymatic assay as a rapid and automated alternative to GCMS for EG quantification. They also support establishing a lower limit for the clinical reportable range of 10mg/dL for the enzymatic assay, rather than using limit of quantification of 5 mg/dL.

Low vacuum (3mL) rapid serum tubes offer better protection from hemolysis than plasma separator tubes collected in the emergency department.

IntroductionUse of Pneumatic tube systems (PTS's) poses a risk to inherently unstable protein therapeutics. Mechanical stress caused by those systems can lead to aggregation, compromising product safety and quality. However, PTS's are widely used in hospitals, and contradictory effects on protein stability have been reported.MethodsWe studied whether mechanical stress levels differ between hospitals and routes, potentially leading to different findings regarding protein aggregation. By transporting a mechanical sensor on nine different PTS routes in seven different hospitals, we quantified the accelerations that protein therapeutics experience in a specific PTS setup.ResultsIt was found that the maximum acceleration within the different PTS setups was similar. However, transportation times differed up to 4-fold, leading to varying amounts of cumulative stress.ConclusionThe cumulative and maximum stress quantified can be compared to stress found in studies investigating protein stability, which justifies the usage of mechanical sensors for risk evaluation. The differences in stress found underscore the importance of evaluating handling practices individually in each hospital, for each therapeutic protein.

Rapid coagulation assessment is crucial in emergencies, especially with acute bleeding, where timely intervention prevents shock and circulatory failure. Viscoelastic tests (VET) offer real-time insights into clot formation, fibrinolysis, and overall coagulation dynamics, often surpassing conventional lab tests. To accelerate diagnostics, hospitals use pneumatic tube systems (PTS) for blood transport. However, the effect of PTS transport on VET results remains unclear, especially with newer VET technologies and in critically ill patients, who may be more vulnerable to acceleration forces. The VETaPT (Viscoelastic Testing after Pneumatic Tube Transport) trial investigates whether PTS transport influences results of three next generation VET and platelet function testing in healthy volunteers and critically ill septic patients. It explores if acceleration during transport alters coagulation and platelet function parameters and whether septic patients exhibit increased susceptibility due to their altered coagulation profiles. A goal is to define an acceleration threshold above which PTS-related effects become clinically relevant. This threshold could allow assessment of transport suitability based on force data alone, supporting wider clinical application without repeated blood testing. This prospective, randomized clinical trial includes both healthy volunteers and critically ill septic patients. Paired blood samples are collected and randomly assigned to either manual or PTS transport, with each subject serving as their own control. Acceleration forces during PTS transport are continuously recorded using a three-axis accelerometer. Samples are analyzed using standard lab tests and following point-of-care devices: ClotPro®, ROTEM® sigma, Multiplate®, and TEG6s®. The primary outcome is the difference in coagulation parameters between transport methods, evaluated in the context of measured acceleration forces. This is the first study to systematically compare multiple next generation VET and platelet aggregation systems in both healthy and septic patients under controlled PTS transport conditions. It is hypothesized that PTS-induced acceleration may alter test results. Identifying a critical threshold could ensure safe, rapid blood transport without compromising diagnostic quality, potentially reducing personnel needs and expediting therapy initiation. Ethics approval was obtained from the responsible committee of the Technical University Dresden (BO-EK-12012024_1). The study is registered with the German Clinical Trials Register (DRKS00036231).

The rapid and efficient transportation of therapeutic monoclonal antibody (mAb) dosing solutions, prepared in intravenous (IV) infusion containers (e.g., IV bags), from pharmacy departments to target locations within hospital campuses globally requires the use of pneumatic tube systems (PTSs). Evaluating the impact of hospital pneumatic tube system (PTS) transportation on the quality attributes of mAb dosing solutions poses significant challenges for pharmaceutical companies. Herein, we present a novel, first-of-its-kind laboratory-scale PTS transportation model capable of assessing the effects of hospital PTS transportation on the product quality of therapeutic mAbs. The laboratory-scale PTS transportation model generated shock and vibration stresses comparable to those experienced in a model hospital PTS transportation. The impact on the product quality of a test mAb due to model hospital PTS transportation was comparable to that observed with laboratory-scale PTS transportation. We found that the impact of PTS transportation on product quality was influenced by the cumulative stress levels experienced by the mAb. Additionally, the product quality was affected by the type of surfactant. The effectiveness of removing air headspace from an IV bag prior to PTS transportation, as a means to mitigate the product quality impact, was also influenced by cumulative PTS stress levels. PTS transportation, with or without stabilizing surfactant in the dosing solution, did not negatively affect the conformational stability, the tertiary structure, or the potency of the test mAb. This study demonstrates a practical approach for designing laboratory-scale PTS transportation studies to assess the risk to product quality of a given mAb due to hospital PTS transportation, determine the residual surfactant (e.g., polysorbate 80/PS80) level needed for protein stabilization, and establish safe transportation and handling practices when using hospital PTS systems.

Evaluating accelerations across multiple routes of a pneumatic tube system to ensure sample integrity for LDH measurement.

ABSTRACTObjectivesNeonatal patients present a challenge to the clinical laboratory because of their low blood volume. The Sysmex XN‐series features a predilution (PD) mode allowing hematologic measurements with only 20–50 μL of blood. We verified the PD mode for analysis of selected hematologic parameters in 50 μL microsamples.MethodsMicrosamples were prepared from adult EDTA blood. White blood cell count (leukocytes, neutrophils, and lymphocytes) and red blood cell parameters (erythrocytes, hemoglobin, hematocrit, mean cell volume, and reticulocytes) were evaluated. The imprecision of the PD mode was evaluated over 3 days, and the accuracy was assessed by method comparison with the standard whole blood mode. The effect of capillary sampling, microsample stability during storage, and pneumatic tube transportation was evaluated. Finally, the bias was reproduced in a small sample of pediatric patients.ResultsFor white blood cells, the bias was ≤ 5.4% (95% CI: 4.5–6.2) and imprecision was below 3.5% (except at the lowest levels). Capillary sampling had little effect on PD analytical performance (bias ≤ 0.7% and imprecision ≤ 4.7%) and white blood cell counts were stable for 7 h at room temperature and after pneumatic tube transportation. The red blood cell parameters generally exceeded the allowable bias and imprecision. The bias of the pediatric samples remained within the 95% PI for the method comparison studies.ConclusionThe PD mode has acceptable analytical performance and preanalytical stability for white blood cell counts but not for red blood cell parameters. It may offer a low‐volume alternative for hematologic monitoring.

Arterial hypertension is one of the most important public health problems, especially in developed countries. The quality and calibration of blood pressure (BP) equipment used for non-invasive blood pressure (NIBP) measurement are essential to obtain accurate data that support correct medical diagnostics. This paper includes the hardware and software description of a flexible, low-cost and algorithm-independent calibrator prototype that can be used for the static and dynamic calibration of automated blood pressure measuring devices (ABPMDs). In the context of this paper, the meaning of calibrator flexibility is mainly related to its ability to adapt or change easily in response to different situations in terms of the calibration of ABPMDs that can use a variety of calibration settings without the need to use specific oscillometric curves from different ABPMD manufacturers. The hardware part of the calibrator includes mainly an electro-pneumatic regulator, used to generate dynamic pressure signals with arbitrary waveforms, amplitudes and frequencies, a pressure sensor, remotely connected through a pneumatic tube to the blood pressure (BP) cuff, a blood pressure release valve and analog conditioning circuits, plus the A/D converter. The software part of the calibrator, mainly developed in LabVIEW 20, enables the simulation of oscillometric pressure pulses with different envelope profiles and the implementation of the main algorithms that are typically used to evaluate systolic, diastolic and mean arterial pressure values. Simulation and experimental results that were obtained validate the theoretical expectations and show a very acceptable level of accuracy and performance of the presented NIBP calibrator prototype. The prototype calibration results were also validated using a certified NIBP calibrator that is frequently used in clinical environments.

In hospitals, IV bags can be prepared in advance for logistical and microbial safety reasons in a compounding unit and then transported to wards. Transport of protein drugs using a pneumatic tube system has been reported to result in high particle levels. In this study, pneumatic tube transport of trastuzumab in saline polyolefin bags was compared to delivery by hospital porters using an electric platform truck in an underground tunnel system. The transport was tracked using designed smart labels. Two strategies to prevent particle formation, removing headspace and adding the surfactant polysorbate 20 were evaluated. The transport by pneumatic tube had a higher level of shock and vibration than truck delivery. The total particle count measured using flow microscopy also increased more for pneumatic transport than for transport by vehicle. Removing the headspace decreased particle formation for both transports. Surfactant decreases particles over 10 µm for trastuzumab in saline IV bags but increases the total particle levels. Pneumatic tube transport of saline in polyolefin bags resulted in high particle levels and surfactant increased the total particle count. Removing headspace is a measure that can be incorporated into compounding practices to cover for inadequate surfactant levels in IV bags.

Abstract CONTEXT: A pneumatic tube system (PTS) can speed up the transportation of specimens to the laboratory, but they may also undergo acceleration/deceleration, high speeds, and changes in air pressure. AIMS: This study aims to determine different serum hemoglobin levels among the specimens sent using PTS and manual transport. SETTINGS AND DESIGN: A cross-sectional study included 40 healthy adult subjects whose specimens were sent to the Central Laboratory of Central General Hospital-Rumah Sakit Umum Pusat (RSUP) Dr. M. Djamil Padang from May to October 2023. Venous blood was collected aseptically in the cubital fossa region, and 3 mL of venous blood was inserted into the tube containing clot activator with gel separator. SUBJECTS AND METHODS: Specimen delivery was carried out from the same distance (1.500 m) using two methods. The first tube was sent using PTS (at the speed of 6 m/s), while the second tube was transported manually by an officer (human courier). STATISTICAL ANALYSIS USED: Serum hemoglobin was examined using hematology analyzer. Statistical analysis was conducted using the Mann–Whitney U-test, and P < 0.05 was considered statistically significant and was examined using JASP. The average age of the subjects was 31.6 (5.5) years, and the majority (85%) were females. RESULTS: Differences in serum hemoglobin levels (g/dL) sent using PTS and manual transport, respectively, were 0.0 (0.0–0.3) versus 0.0 (0.0–0.3) with P = 0.873. CONCLUSIONS: There were no significant differences in serum hemoglobin levels between specimens sent using PTS at 1.500 m and the speed of 6 m/s with manual transport.

Abstract The pneumatic tube plays a critical role in the frequency response of the pressure measurement system, which also greatly affects the accuracy of the measurement data. This paper applied the Monte Carlo uncertainty qualification method to the pressure measurement tube system frequency response and studied the effects of four parameters, including tube length, radius, temperature, and source pressure, on uncertainty characteristics for a given tube system configuration. The reported results show the technique's applicability and flexibility and the limitations of GUM. It is found that the frequency response and corresponding uncertainty are not directly related to frequency but are closely related to the natural frequencies. Comparative experimental results show that the longer tube significantly reduces the system's natural frequencies and intensifies the phase lag. In addition, larger tube radius and source pressure result in larger amplitude response peaks. Closed to the natural frequencies, with the increase of the parameter, the uncertainties of frequency response value and the corresponding variation range increase for tube radius and source pressure while decreasing for temperature and tube length.

Impact of pneumatic tube transportation on the aggregation of monoclonal antibodies in clinical practice

Abstract Timely reporting of critical values serves as a quality indicator for the National Patient Safety Goal. Since the oncology inpatient unit at our institution has the highest number of critical values and often struggles to meet the targeted goal of timely results acknowledgement, this prompted a performance improvement initiative. By utilizing the Institute for Healthcare Improvement (IHI) Model for Improvement, the study aimed to decrease the time from specimen collection to acknowledgment of a complete blood count critical values (overall TAT). Three key metrics were monitored, including unit turnaround time (time from collection to receipt in laboratory; uTAT), laboratory turnaround time (time from receipt in laboratory to verified results) and timely critical value acknowledgment rate (% acknowledgement within 30 minutes). Quality improvement tools such as process maps and fishbone diagrams were employed, and two areas for improvement were identified. Firstly, it was observed that samples collected by the phlebotomists were delivered in batch to the laboratory via carts. However, samples collected by nurses were sent to the laboratory via a pneumatic tube. Hence, the uTAT varied drastically due to the different delivery methods. Secondly, the mode of alerting providers regarding critical values, which was via telephone calls from telecommunication staff, was deemed disruptive and redundant, as the providers often were already aware of the results from the electronic medical record (EPIC). Two multi-cycle Plan-Do-Study-Act (PDSA) interventions were implemented by a multidisciplinary team. The first focused on sending samples via pneumatic tube. The second PDSA intervention focused on a direct clinician acknowledgment of critical values within EPIC, by creating an auxiliary column on the EPIC patient list. Consequently, the overall TAT decreased from a median time of 167 minutes in July 2021 to 140 minutes by March 2022 in the oncology inpatient unit, with a sustained result (139 minutes) by October 2023. This reduction was driven by the standardization of pneumatic tube delivery system; the uTAT decreased from a median time of 104 minutes to 46 minutes by March 2022 and remained low at 52 minutes by January 2024. Notably, the rate of timely acknowledgment of critical value results worsened, dropping from 67% to as low as 51 % (March 2022) and improved to 64% by January 2024. It was realized that this unintended consequence was attributed to the decrease in uTAT, leading to more critical value results reported in early morning when there was less staffing. Despite the worsening in timely critical value acknowledgment, the overall TAT showed a discernible reduction. The application of IHI methodology played a pivotal role in expediting result reporting. Subsequent steps will focus on utilizing secure communication channels to augment the success rate of critical values acknowledgment within 30 minutes.

Abstract Introduction/Objective Timely delivery of blood products can be of utmost importance to providing quality care. We aimed to validate the use of a high-speed pneumatic tube system (PTS) that was already installed at our hospital. By reducing delivery times, patient resuscitation and survivability can be increased. Methods/Case Report We followed the Association for the Advancement of Blood & Biotherapies (AABB) guidelines to validate a PTS in a large tertiary academic medical center. The requirements include: verifying product suitability, ensuring product integrity, temperature monitoring, transportation time measurements, and proper packaging and tracking of product receipt. We validated the transfer of packed red blood cells (PRBC), plasma, platelets, and cryoprecipitate from the central blood transfusion services lab (BTS) to nursing stations in a separate building up to 1500 feet (>1/4 mile) away using a Swisslog Translogic® PTS Inclusion with foam inside the PTS carriers helped reduce bumps during transit and insulated products from heat. Results (if a Case Study enter NA) The mean temperature of the PRBC was 6.6 degrees Celsius and none exceeded the AABB maximum of 10 degrees Celsius. The mean time for blood products transit to the nursing stations was 3 minutes (m) and 33 seconds (s). The median time was 3m 31s, and it ranged from 2m 18s to 5m 38s. The PTS reduced delivery times of blood products by up to 10-12 minutes compared to manual porters. Conclusion Transporting blood products via PTS is an efficient method that reduces the required manpower and leads to better utilization of resources. However, it is essential to validate the PTS system before implementing it operationally.

BackgroundPseudohyperkalemia is well known in acute or chronic lymphocytic leukemia, but it is very rare in acute myeloid leukemia (AML). The lab flagging system for leukocytosis to prevent pseudohyperkalemia may not work.Case presentationA 55 year-old white man with AML was sent to emergency department for transfusion due to severe anemia. Blood test showed severe leukocytosis and elevated potassium. Repeated blood test showed his potassium was even higher. Anti-hyperkalemic medical treatment was given. He was then diagnosed with pseudohyperkalema.InvestigationI was repeatedly reassured that the lab’s manual flagging system for leukocytosis was the key in reaching the correct diagnosis. My persistent inquiries, however, revealed that the flagging system was not functioning in the care of this patient. It was clinicians’ suspicion of pseudohyperkalema that led to the correct diagnosis, although the clinicians’ recommendation of obtaining a heparinized plasma for test did not play a role because all blood samples were already heparinized. The cause of pseudohyperkalemia was pneumatic tube transport. After this incident, our laboratory is investigating the options of using the Laboratory Information System to automatically flag the results and Clinical Laboratory Scientists to make the chemistry team more aware of potentially erroneous potassium results due to pseudohyperkalemia.ConclusionsPseudohyperkalemia associated with leukocytosis still occurs. This is the first case of pneumatic tube transport causing pseudohyperkalemia associated with AML. When significant leukocytosis, thrombocytosis, hyperproteinemia, or hyperlipidemia is present, whole blood should be utilized for potassium measurements and walked to the lab instead of sent by pneumatic tube transport. Even in a lab with a manual flagging system, there is still room to improve by implementing an automatic flagging system.

Pseudohyperkalemia (falsely elevated serum potassium) must be distinguished from true hyperkalemia to avoid unnecessary treatment. Some case reports suggest that pneumatic tube transportation may increase the risk of pseudohyperkalemia, but comprehensive research on the topic is lacking. Here, we aimed to assess the association between WBC levels, pneumatic tube transport, and pseudohyperkalemia prevalence. We analyzed 1188 samples collected from 240 patients between 2019 and 2022. Samples with elevated WBC counts (≥ 100 × 103/μL) and potassium levels were included in this study. The method of specimen transportation was documented. Pseudohyperkalemia was observed (7/390) in specimens transported using pneumatic tubes. No pseudohyperkalemia was identified with manually transported specimens (0/132). Every increase in WBC count by 100 × 103/μL in the specimens multiplied the odds ratio of pseudohyperkalemia by 3.75 when delivered with pneumatic tube. The prevalence of pseudohyperkalemia increased as WBC count increased, especially at WBC counts greater than 200 × 103/μL. Pneumatic tube transport poses a risk for pseudohyperkalemia in patients with extreme leukocytosis. Physicians should anticipate odd potassium levels when interpreting blood test results. Redrawing of blood samples, manual specimen transportation, or point-of-care testing are suggested to prevent further misdiagnosis.

We aimed to develop an automated, low-volume method for thrombocyte counting in capillary blood using the Sysmex predilution (PD) mode. Microsamples were prepared by resuspension of 50 μL blood in 300 μL DCL CellPack. Thrombocyte counting was done in the impedance (PLT-I) and fluorescence (PLT-F) channels. The imprecision and bias was evaluated in >394 microsamples from adult blood. Preanalytical factors (skin-piercing, storage, and transportation in our pneumatic tube system) was assessed, and studies on pediatric microsamples were made for comparison. The improvement in analytical quality and turnaround time was examined. For PLT-F, the imprecision was 1.1%-3.7%, and the bias was 10.1% (95% CI: 8.8-11.3). After skin-piercing, the bias was 8.1% (95% CI: 5.6-10.6) and the imprecision 1.9% (95% CI: 1.3-2.5). Thrombocyte counts kept stable after 4 h at room temperature (94.8% [95% CI: 93.2-96.4]) and after pneumatic tube transportation [6.7% (95% CI: 4.8-8.6)]. The bias of the PD mode for pediatric microsamples was 13.0% (95% CI: -8.4-34.4) in the PLT-F channel. The automated method had a considerably lower imprecision than the existing manual thrombocyte counting method and reduced turnaround times. The automated microsample method offers a low-volume alternative for measurement of thrombocytes. The method appears useful also in pediatric samples.