ABL90 FLEX Research Articles

Verification of automated review, release and reporting of results with assessment of the risk of harm for patients: the procedure algorithm proposal for clinical laboratories.

Autoverification increases the efficiency of laboratories. Laboratories accredited according to ISO 15189:2022 need to validate their processes, including autoverification, and assess the associated risks to patient safety. The aim of this study was to propose a systematic verification algorithm for autoverification and to assess its potential risks. The study was conducted using retrospective data from the Laboratory Information System (LIS). Seven laboratory medicine specialists participated. Autoverification rules were defined for analytes in serum, stool, urine and whole blood determined on Alinity ci (Abbott), Atellica 1500 (Siemens) and ABL90 FLEX (Radiometer). Criteria included internal quality control results, instrument flags, hemolysis/icteria/lipemia indices, median patient values, critical values, measurement ranges, delta checks, and reference values. Verification was performed step by step. Risk analysis was performed using Failure Modes and Effects Analysis and the Risk Priority Number (RPN) was calculated. During the study, 23,633 laboratory reports were generated, containing 246,579 test results for 167 biochemical tests. Of these, 198,879 (80.66 %) met the criteria for autoverification. For 2,057 results (0.83 %), the experts disagreed with the autoverification criteria (false negatives). Discrepancies were mainly associated to median and delta check values. Only 45 false positives (0.02 %) were identified, resulting in an RPN of 0 for all cases. The autoverified and non-autoverified results showed high agreement with the expert opinions, with minimal disagreement (0.02 % and 0.83 %, respectively). The risk analysis showed that autoverification did not pose a significant risk to patient safety. This study, the first of its kind, provides step-by-step recommendations for implementing autoverification in laboratories.

Abstract 4136448: A Novel Cardiomyocyte Targeting Peptide Enhances Calcium Handling

Introduction: Intracellular calcium handling plays a central role in cardiac contractility and relaxation. Genes such as the Ca 2+ -ATPase pump (SERCA2a) and the Dihydropteridine reductase (DHPR) enzyme are especially important in the cycling of intracellular calcium. As prior research has established a link between treatment with our cardiac targeting peptide (CTP: a 12-amino acid, cardiomyocyte-specific cell penetrating peptide) and upregulation of calcium-handling genes such as SERCA2a and DHPR, we hypothesized that treatment with our novel hybrid cardiac targeting peptide (hCTP: positions #3 and 11 replaced with the D-enantiomer form of the amino acids) will improve intracellular calcium handling in human cardiomyocytes (CMCs) by increasing expression of key calcium handling genes instrumental in sequestering calcium in diastole and lowering cytosolic levels. Methods: To test hCTP’s calcium handling abilities, CMCs were plated on day 1 and allowed to settle for 24 hours, after which they received daily treatment with various concentrations of hCTP (1-25µM) for three days. On day 5, cells underwent either intracellular calcium measurements using the FLIPR 6 Calcium assay or were prepared for western blotting. Western blotting was performed to determine the protein concentrations of SERCA2a and DHPR, as compared to a GAPDH control. To test hCTP’s intrinsic calcium handling abilities, various concentrations of hCTP were mixed with a constant amount of elemental calcium dissolved in water. After 20 min at 37 o C, the concentration of free Ca 2+ was measured with an ABL90 Flex Plus radiometer. Results: In CMCs, treatment with hCTP led to a decrease in cytosolic calcium in a dose dependent fashion; concentrations as low as 1µM led to a significant decrease in cytosolic calcium (p< 0.0001 for all groups). Western blots performed on the treated CMCs revealed an increase in expression of both DHPR and SERCA2a, normalized to GAPDH control. Outside of the cellular environment, hCTP did not appear to display inherent calcium sequestring properties, suggesting that improvements in calcium handling are due to upregulation of gene expression. Conclusion: hCTP appears to lower cytosolic calcium and improve calcium handling through upregulation of SERCA2a and DHPR. Our data indicates that hCTP is worth pursuing as a stand-alone, cardio-selective therapy for cardiomyopathies involving calcium mishandling.

Critical values for carbon monoxide in cases admitted to the emergency department in a local hospital

Abstract Carbon monoxide (CO) poisoning has been an important concern in winter particularly due to malfunctioning coal stoves, in many developing countries, including Turkey. Winter months, especially February, were the most dangerous periods for CO exposure. Carbon monoxide has no color or smell so has known as the silent killer. Brain, heart, and other organs are under risk in CO poisoning. Because patients usually present with non-specific symptoms, CO poisoning should be considered in the differential diagnosis of unexplained nausea and vomiting, neurological or cardiac signs and symptoms. Carboxyhemoglobin (COHb) is a reliable marker to monitor the patient. Lactate is also important as a measure of impaired systemic oxygen delivery. Fifteen patients with a diagnosis of CO poisoning were included in the study. This is the number of all cases admitted to the emergency in the last one and a half months in our local hospital located in a town with almost 48.918 residents. Blood gas analysis was performed by ABL90 FLEX, Radiometer. Reference for COHb was 0.6-1.5 % and for lactate was 0.5-1.6 mmol/L. Troponin I levels were also analyzed in some patients to assess possible myocardial ischemia. Troponin levels were analyzed by ARCHITECT i2000, Abbott and reference range was <16 ng/mL in woman, <34 ng/mL in men. Graph Pad Prism program was used for statistical analysis of the data. We had 15 cases aged between 4-56 years with COHb values with panic values (> 20%) except two of the cases with values 16.5% and 19%. The female-male ratio was 6/9. On admission to the Emergency Department, 46.6% of patients (n=7) had headache and vomiting, 40% of patients (n=6) had headache, 6.6% (n=1) fatigue and 6.6% of patients (n=1) had syncope. Median value of COHb % was 23.7(16.5-40.8), lactate was 1.9 (0.8-4.8), pH was 7.39 (7.30-7.47). Excluding three patients as outliers, lactate levels had a good correlation with carboxyhemoglobin values (R2=0.9413). It was notable that 1 patient had a higher-than-normal Troponin I level (24.9 ng/mL) who has highest lactate level (4.8 mmol/L). Four of the patients, from the same family was admitted for suspected food poisoning for the symptoms of nausea, vomiting, diarrhea. A diagnosis of CO poisoning was made after a COHb value between 16.5-25.7% for these patients. This was very critical for the accurate treatment given to those patients being hyperbaric oxygen treatment in CO poisoning cases. CO poisoning should be considered in patients admitting to the emergency department with complaints of headache, dizziness, weakness, nausea, and vomiting. Reporting panic values is a means of alerting the clinician for the right diagnosis.

Prehospital blood gas analyses in acute patients treated by a ground-based physician-manned emergency unit: a cohort study

BackgroundThe prehospital patients treated by ambulances and mobile emergency care units (MECU) are potentially critically ill or injured. Knowing the risks of serious outcomes in these patients is important for guiding their treatment. Some settings allow for prehospital arterial blood gas analyses. This study aimed to assess the outcomes of prehospital patients in relation to their prehospitally measured lactate, pH, and CO2 levels. The primary outcome was 7-day mortality.MethodsThis register-based cohort study included patients with one or more prehospital blood gas analyses during their prehospital treatment by a physician-manned MECU, from January 2015 to December 2018. The blood samples were analyzed on an ABL90 Flex analyzer. Absolute values with percentages and odds ratios (OR) with 95% confidence intervals (CI) were calculated for the primary and secondary outcomes within prespecified subgroups.ResultsThe study included 745 patients, with an overall 7-day mortality rate of 20.0%.Lactate levelThe 7-day mortality rates were 11.5% in patients with normal lactate levels (< 2.0 mmol/L), 14.4% with intermediate lactate levels (2.0–3.9 mmol/L), and 33.0% with high lactate levels (≥ 4.0 mmol/L). This corresponded to an OR of 1.30 (95% CI: 0.75–2.24) in the intermediate lactate group (2.0–3.9 mmol/L) and an OR of 3.77 (95% CI: 2.44–5.85) in the high lactate group (≥ 4.0 mmol/L), compared to the reference group with normal lactate.pH levelThe ORs of 7-day mortality rates were 4.82 (95% CI: 3.00–7.75) in patients with blood pH of < 7.35 and 1.33 (95% CI: 0.65–2.72) in patients with blood pH > 7.45, compared to the reference group with normal pH (7.35–7.45).CO2 levelThe ORs of 7-day mortality rates were 2.54 (95% CI: 1.45–4.46) in patients with blood CO2 of < 4.3 kPa and 2.62 (95% CI: 1.70–4.03) in patients with blood CO2 > 6.0 kPa, compared to the reference group with normal CO2 (4.3–6.0 kPa).ConclusionsThis study found a strong correlation between increasing 7-day mortality rates and high blood lactate levels, low levels of pH, and abnormal CO2 blood levels, in prehospital patients undergoing prehospital blood analysis.

PULM7: Toward Automatic Control Of Arterial Blood Paco2 Using Artificial Lung Exhaust Gas CO2 As A Surrogate

Purpose: Current clinical Extra Corporeal CO2 removal systems rely on human intervention to adjust to changes in patient activity. Previous studies have investigated the use of capnography for measurement of arterial blood carbon dioxide tension (PaCO2) using artificial lungs (AL). The presented work demonstrates an initial implementation of a controller that directly monitors and regulates PaCO2 using exhaust gas CO2 (EGCO2) measurements. Method: The system operates through two cycles, namely measurement and control. First, the sweep gas flow through the AL is temporarily (~60s) reduced to ~400 mL/min to allow the CO2 concentration on the blood and gas phase of the AL to equilibrate. This allows for EGCO2 (measured via a CO2Meter GC-0017) values to be used as an estimate of PaCO2. The control cycle is based on Proportional-Integral-Derivative (PID) principle wherein the system automatically modulates sweep gas flows through the AL to minimize the difference between the desired PaCO2 and the estimated PaCO2 (i.e., measured EGCO2). Blood samples were intermittently collected at the inlet of the AL to monitor actual PaCO2 (measured via a Radiometer ABL800 Flex blood gas analyzer). The in vitro study setup (Fig. 1) consists of a Novalung iLA oxygenator (main AL) and a Capiox RX25 oxygenator (conditioning AL) connected in parallel to model a typical ECMO circuit. The blood reservoir mimics the blood volume (7 L) while the centrifugal pump simulates cardiac output (fixed at ~5 L/min) of a patient. Blood flow through the main AL (AV shunt) was regulated at ~1 L/min using a Hoffman clamp. CO2 concentration in the sweep gas through the conditioning AL was modulated to simulate metabolic activity. The baseline CO2 concentration measured at the outlet of the conditioning AL that projects reservoir PaCO2 level when the main AL is not operational. The baseline blood concentration was varied between 45 and 90 mmHg representing all levels of normocapnia and hypercapnia. Results: Prior to the controller testing, a feasibility study was performed to determine the accuracy of capnography technique in calculating the PaCO2 using the AL. A total of forty-two blood samples were collected at blood flow rates of 0.5, 0.6 and 1.0 L/min. The results show a good correlation between PaCO2 and EGCO2 (r2=0.824, P<0.001). There was a reasonable degree of agreement between the PaCO2 and EGCO2 with accuracy (bias or mean difference between PaCO2 and EGCO2) of 6.04 mmHg with a precision (95% limits of agreement) of ± 9.62 mmHg (Fig. 2). Despite the limitation of the AL in estimating PaCO2 using EGCO2, the PID controller implementation demonstrated that average reservoir CO2 concentration can be maintained at 44.23 ± 8.7 mmHg for a target PaCO2 of 40 mmHg (Fig. 3),against baseline blood reservoir PaCO2 of 60.76 ± 13.81 mmHg.Figure 1. Image showing in vitro test setup. The bovine blood in the test circuit was anticoagulated (ACT > 1200s) with heparin and maintained at 37°C.Figure 2. a) The regression curve generated between PaCO2 samples and measured EGCO2 b) Agreement between PaCO2 samples and measured EGCO2.Figure 3. a) In vitro test results showing changes in all PaCO2 concentrations in the circuit b) Result summary comparing average reservoir PaCO2 level with target PaCO2

Elevated methemoglobin levels in patients treated with high-dose hydroxocobalamin.

The aim of this study was to assess the impact of hydroxocobalamin (OHCbl) infusion on arterial blood gas and oximetry values in patients with vasoplegic syndrome. Blood samples collected from 95 patients receiving OHCbl infusion were assayed using the ABL90 FLEX Plus blood gas analyzer for the concentration of methemoglobin (MetHb), total hemoglobin (tHb), carboxyhemoglobin (COHb), arterial oxygen saturation (SaO2), arterial oxygen partial pressure (PaO2), and arterial carbon dioxide partial pressure (PaCO2). Interference of OHCbl on these variables was evaluated using the measured difference between the preinfusion and postinfusion samples. Blood MetHb (%) measured after the infusion of OHCbl (5g) were significantly higher than the baseline levels, with a median of 4.8 (IQR, 3.0-6.5) versus 1.0 (IQR, 1.0-1.2) (P < .001). Blood COHb (%) increased from a median of 1.3 (IQR, 1.0-1.8) to 1.7 (IQR, 1.3-2.2) (P < .001) following the OHCbl infusion. No differences were seen in median levels of tHb, PaO2, PaCO2, and SaO2 between pre- and post-OHCbl treatment. The presence of OHCbl in blood clearly interfered with the oximetry measurements of the hemoglobin component fractions by falsely increasing the levels of MetHb and COHb. Blood levels of MetHb and COHb cannot be reliably determined by the co-oximetry when OHCbl is known or suspected.

Hemoglobin determination with point-of-care testing, performance evaluation compared to central laboratory analyzers in transfusion decision, an in vitro and retrospective study.

Point of care (POC) analyzers are an integral part of the patient care. Transfuse can be an emergency decision, not being a benign act, it is necessary to ensure that the hemoglobin value measured by the POC are comparable with the reference analyzer. The objective is to compare the analytical performance of three POCs: ABL800 Flex, Hemocue and iSTAT and a central laboratory analyzer: XN-10 and the impact on the transfusion decision. An in vitro study was performed in 50 patients for whom a hemogram had been prescribed on the XN-10, the hemoglobin determination was performed in parallel on the three POCs. Then, retrospective study was performed to compare the hemoglobin values returned for matched samples in routine practice, 5505 for ABL800 Flex, 55 for Hemocue and 70 for iSTAT were analyzed. In vitro study shows systematic biases in the measurement of hemoglobin between the different analyzers, overestimation for the ABL800 Flex and the Hemocue, underestimation for the iSTAT. These biases are accentuated in current practice for iSTAT but decreased for ABL800 Flex. In the transfusion decision range from 70 to 100 g/L, there were 8.6% of clinically discordant results between the reference method and ABL, 34.8% for Hemocue and 21.4% for iSTAT. In addition to systematic biases, many additional factors may be involved for variation in hemoglobin measurement with POC. Thus, in the case of urgent transfusion decisions, sending a hemogram on a central laboratory analyzer seems to be essential, while being compatible with a life-threatening emergency.

Evaluation of the Accuracy of Cr and BUN Using the ABL90 FLEX PLUS Blood Gas Analyzer and the Equivalence of Candidate Specimens for Assessment of Renal Function.

The ABL90 FLEX PLUS (Radiometer) is a blood gas analyzer that also provides creatinine (Cr) and blood urea nitrogen (BUN) results. We assessed the accuracy of the ABL90 FLEX PLUS to measure Cr and BUN and find suitable candidate specimens against primary specimens (heparinized whole-blood (H-WB)). Paired H-WB, serum, and sodium-citrated whole-blood (C-WB) samples (105) were collected. The Cr and BUN levels in the H-WB using the ABL90 FLEX PLUS were compared with those of the serum using four automated chemistry analyzers. The suitability of the candidate specimens was assessed at each medical decision level according to the CLSI guideline EP35-ED1. The respective mean differences of the ABL90 FLEX PLUS for the Cr and BUN were below -0.10 and -3.51 mg/dL compared to the other analyzers. The systematic differences between the serum and the H-WB at the low, medium, and high medical decision levels were all 0% for Cr, but those of the C-WB were -12.96%, -11.81%, and -11.30%, respectively. Regarding imprecision, the SDserum/SDH-WB ratios at each level were 0.14, 1.41, and 0.68, whereas the SDC-WB/SDH-WB ratios were 0.35, 2.00, and 0.73, respectively. The ABL90 FLEX PLUS provided Cr and BUN results comparable with the four widely used analyzers. Among the candidates, the serum was suitable for Cr testing using the ABL90 FLEX PLUS, while the C-WB did not satisfy the acceptance criteria.

Comparison of ionised calcium measured using a portable analyser to a reference method in healthy dogs.

To compare the ionised calcium measured on a portable analyser (iSTAT, Abbott) to a reference method. Blood samples from 39 apparently healthy dogs were analysed in duplicate using a portable analyser and a reference method (Radiometer ABL800 FLEX). Bland-Altman plots and Passing-Bablok regression were used to assess constant and proportional bias between the two instruments. A within-assay percentage coefficient of variation and total error (TE) was calculated for both analysers. The reference interval was calculated for the portable analyser using the robust method with confidence interval bootstrapping. The Bland-Altman plot showed a -0.036 mmol/L difference between the two instruments (95% confidence limit -0.08 to 0.01 mmol/L; limits of agreement -0.07 to 0.006 mmol/L). Neither the Bland-Altman plot nor the Passing-Bablock regression (slope -0.03; 95% confidence interval -0.08 to 0.19 and intercept 1; 95% confidence interval 0.83 to 1.2) showed significant proportional bias. The coefficient of variation for the portable analyser was 1.08%, compared to 0.78% for the reference method with a total error of 3.5% for the portable analyser. The estimated population-based reference interval for ionised calcium using the portable analyser is 1.23 to 1.42 mmol/L. For the healthy dogs in this study, compared to the reference method, the portable analyser showed no significant bias for measurement of ionised calcium. Further studies including hyper and hypocalcaemic dogs are required to determine clinical impact of the use of this analyser.

Comparison of blood gas results obtained on Abbott i-Stat® and on Radiometer ABL 800 Flex® analyzers Impact for the clinical decision

Point of care testing (POCT) tests are needed to assess severity and to help for triage in hospital and in prehospital settings. Before their use, the analytical performances of POCTs have to be compared with central laboratory reference methods. In this study, we describe the comparability of results obtained by either the Abbott i-STAT® System POCT handheld device or the blood gases analyzer of the central laboratory of our hospital. Sample blood from 37 septic patients admitted to the intensive care unit (ICU) were assayed by Abbott i-STAT® System POCT and Radiometer ABL800 Flex® lab analyzer. Studied parameters were as follows: pH, pO2, pCO2, base excess (BE), HCO3-and lactate. Comparability was evaluated using Bland-Altman method. The clinical value for possible mismatch issued of values differences was also assessed. Quite acceptable correlations in results of POCT and laboratory analyzer were observed with R²most of time above 0.85. Bland-Altman analysis showed a bias of 1.26% for Abbott i-STAT® System POCT vs laboratory. Abbott i-STAT® System POCT handheld device is comparable to Radiometer ABL800 Flex® lab analyzer and concordant with laboratory analysis. Abbott i-STAT® System POCT handled device could be used in the prehospital settings in order to evaluate the severity of sepsis.

Determination of the compatibility between arterial samples and blood samples from arteriovenous fistulas for ESRD patients

Arterial blood gases (ABG) is a common and gold standard procedure and is often used to assess acid-base status and electrolytes. Arterial blood sampling is technically difficult and painful and causes rare but serious complications for the patient (such as vascular injury or embolism). The blood gas analysis of samples drawn from the arteriovenous fistula (AVF) requires fewer punctures and is a relatively safer and less painful procedure for the patient. The study included (22) patients and a blood gas analyzer (ABL800 FLEX PLUS blood gas analyzer) was used. The results showed that there were no clinically significant differences between the arterial blood sample and the arteriovenous fistula sample.

Pediatric ionized calcium reference intervals from archived radiometer data

BackgroundMeasurement of ionized calcium (iCa) reflects bioavailable calcium and has significant utility in children. However, robust pediatric iCa reference intervals (RI) have not been well-established. In this study, we retrospectively calculated RI for iCa in a pediatric population by accessing archived data acquired on Radiometer instruments and applying stringent exclusion criteria. MethodsData saved on 4 Radiometer ABL800 FLEX blood gas analyzers were queried. Exclusion criteria were applied based on information available from these instruments. iCa results were plotted and inflection points were visually identified. Following outlier removal and partition verification, age-specific RI were calculated using a nonparametric rank order approach from > 5,000 individuals. Finally, the stringency of the exclusion criteria was assessed by calculating RI from additional results in the dataset and comparing to existing in-house ranges. ResultsSix age-specific iCa partitions were established from 0 to 19 years. Relative to adults, wider ranges for the central 95th percentile were observed early in life that progressively narrowed with increasing age and approached adult concentrations by 2.5 years. Analysis of concurrent data for sodium and creatinine in the dataset suggest the applied exclusion criteria reduced the likelihood of including results from acutely-ill children. ConclusionsNormal concentrations of iCa in children are more variable than adults. Observed differences may reflect the transition from maternally supplied calcium to nutritional sources, the maturation of calcium homeostatic mechanisms, and/or the need for calcium for growth/development. This study also demonstrates the feasibility and advantages of using data archived on Radiometer analyzers to establish pediatric RI. This approach enables rapid, cost-effective evaluation of large datasets and may be a feasible option when prospective or detailed retrospective analyses are not possible.

Accuracy of a point-of-care blood lactate measurement device in a prehospital setting

Point-of-care blood lactate is a promising prognostic biomarker of short-term mortality risk. Portable lactate meters need validation in the prehospital setting before widespread implementation and it is unknown whether the mode of sampling (arterial, capillary or venous) matters. This study aims to compare the StatStrip Xpress Lactate Meter’s (SSX) accuracy to a validated blood gas analyser, ABL90 FLEX (ABL90), in arterial samples in the prehospital environment and to determine if lactate levels measured in venous and capillary blood samples are sufficiently accurate compared to arterial lactate levels. Patients with arterial samples drawn by the prehospital anaesthesiologist for any reason were eligible for inclusion. Simultaneously, three blood samples (arterial, capillary and venous) were analysed on SSX and arterial blood on ABL90. Measurements of agreements were evaluated by Lin’s concordance correlations coefficient (CCC) and Bland–Altman Plots. One-hundred-and-eleven patients were included. SSX showed good accuracy compared to ABL90 in arterial samples with a CCC of 0.92 (95% CI 0.90–0.94). Compared to the arterial samples measured on ABL90, venous samples analysed on SSX showed higher agreement than capillary samples analysed on SSX with CCCs of 0.88 (95% CI 0.85–0.91) and 0.79 (95% CI 0.72–0.85), respectively. Bland–Altman plots showed that SSX lactate measurements in arterial, venous and capillary blood samples all had systematically negative biases compared to ABL90. We conclude that the SSX is accurate in our prehospital setting. Venous samples should be preferred over capillary samples, when arterial samples cannot be obtained.

Первая доклиническая ангиоспастическая фаза ретинопатии недоношенных

Purpose. To evaluate the role of the first preclinical phase in the pathogenesis of retinopathy of prematurity (ROP). Material and methods. 642 premature babies were examined. The gestational age at the time of birth was up to 30 weeks and the weight was up to 1500 g. Ophthalmological monitoring was carried out from 28–30 weeks of postconceptional gestational age. Indirect ophthalmoscopy, digital calibration of retinal vessels, and studies on a wide-field retinal pediatric camera were performed. Dopplerography data of the blood flow in the brain vessels and in the ocular artery were analyzed in 28 children (56 eyes). The partial pressure of oxygen (pO2) and carbon dioxide (pCO2) in capillary blood was studied using Radiometer ABL800 FLEX gas analyzer (normal levels of pO2 are 40–60 mmHg, pCO2 is 35–45 mmHg). Results. It was revealed that the lower the degree of maturity of the child’s body was, the more often retinal arteriospasm was detected. In children with a postconceptional age of 25–27 weeks, arteriospasm was detected in 82% of cases, at 28 – 29 weeks – in 67%, 30 – 32 weeks – in 54% of cases. The degree of angiospasm correlates with a high index of blood flow resistance in the brain vessels and the ocular artery. The predominance of a high index of blood flow resistance in more premature infants with low body weight was revealed.The index of resistance of brain vessels 0.8 and higher, according to dopplerography, is a critical indicator of the threat of ROP development in a premature baby. Conclusion. During retinopathy of prematurity, it is important to detect the first preclinical, antispasmodic phase of ROP development, which lasts about one month and until now practically does not attract the attention of ophthalmologists. In this phase, the pathogenesis of pathological angiogenesis is formed. Further study of the preclinical phase will radically revise the strategy and tactics of diagnosis and treatment of RP. Key words: retinopathy of prematurity, first preclinical angiospastic ROP phase, active ROP phase, scarring ROP phase, autoregulation of retinal vessels, hypoxic and hypercapnic drives.

Resolving Pseudohyponatremia: Validation of Plasma Sodium on Radiometer ABL800 Blood Gas Analyzers for Immediate Reflex Testing.

To perform validation of plasma sodium on blood gas analyzers to reflexively correct erroneous measurements by ion-selective electrodes (ISEs). We compared remnant specimens of whole blood and plasma collected by lithium heparin vacutainer with normal protein concentrations and no lipemia. Whole-blood specimens were tested for sodium concentration on the ABL800 Flex blood gas analyzer, followed by centrifugation for plasma separation, and repeat sodium determination on an aliquot of the plasma only. Also, plasma specimens were analyzed by indirect ISE on the Cobas 8000 series and by direct ISE on the ABL800 Flex for instrument comparison. Plasma aliquots yielded comparable results to the parent whole-blood specimen, with an average change of -1.33 mmol/L (R2 = 0.9727). Comparison of indirect ISE to direct ISE similarly yielded comparable results, with an average change of + 0.8 mmol/L (R2 = 0.9016). Plasma is a valid specimen matrix for use on blood gas analyzers for sodium determination, eliminating the need for re-collection of whole-blood specimens from patients with pseudohyponatremia.

Pediatric Reference Intervals for Point-of-Care Random Glucose in Healthy Children and Adolescents.

Glucose testing at the point-of-care (POC) is routinely used in the diagnosis, prognosis, and monitoring of diabetic states and other clinical conditions. Accurate reference intervals (RIs) are essential in appropriate clinical decision-making. In this study, RIs were established for random glucose (whole blood) in the Canadian Laboratory Initiative on Pediatric Reference (CALIPER) cohort using 2 POC instruments: the Nova Biomedical StatStrip (handheld glucometer) and Radiometer ABL90 FLEX Plus (benchtop instrument). An analytical comparison was also completed between the 2 POC systems and a laboratory-based analyzer (Ortho Vitros 5600). Approximately 400 healthy children and adolescents (birth to 18 years) were recruited with informed consent from community schools or clinics providing care to metabolically stable/healthy children. Random venous samples were collected and run sequentially on the Nova Biomedical StatStrip (whole blood), Radiometer ABL90 FLEX Plus (whole blood), and Ortho Vitros 5600 (serum). RIs and method comparisons between analytical platforms were completed according to CLSI guidelines. Significantly different glucose concentrations were observed in infancy, requiring age-specific partitioning (0-<1 month, 1-<6 months, 6 months-<19 years) on all platforms. Excellent concordance was observed between POC platforms (Pearson r > 0.90), with a small negative bias. Good comparability was observed between POC and laboratory-based platforms (Pearson r > 0.80). This study established comprehensive pediatric RIs for random glucose (whole blood) on modern POC systems in the CALIPER cohort for the first time. Results demonstrate excellent concordance in glucose values between POC systems and good comparability with a laboratory-based analyzer. These data will assist in more accurate clinical decision-making in pediatric healthcare institutions.

Comparison of Sodium and Potassium by Point-of-Care Arterial Blood Gas Analyzer and Venous Serum by Central Laboratory Analyser in Emergency Clinical Decision Making

Introduction: The Emergency Departments (ED) are equipped with Point-of-Care (POC) blood gas analysers (BGA) which deliver fast results on multiple parameters of arterial/venous blood. There is no consensus among ED physicians on the reliability of electrolyte results by POC Arterial Blood Gas (ABG) analysis compared to venous serum electrolyte from Central Laboratory Analyser/Auto-Analyser (CLA/AA). Aim: To compare the electrolyte(sodium and potassium) by POC arterial BGA (ABL800 Flex Radiometer) with venous electrolyte by CLA (Beckman Coulter AU 5800). Materials and Methods: This cross-sectional study was performed in the ED and Central Laboratory of the tertiary hospital from 1st July 2018 to 31st July 2019. A total of 254 critically ill adult patients with various etiologies, were enrolled in the study. The arterial and venous blood samples were collected for electrolyte measurement within a span of 15 minutes. The ABG samples, anticoagulated with liquid heparin, were processed in POC BGA. The venous samples collected in plain tubes were analysed in CLA. The results of sodium and potassium were compared by the mean, correlation coefficient, p-value, and Bland Altman Plots {95% Limit of agreement (LOA)}. Results: Out of 254 paired samples (mean age: 63±15 years), 157 (61.8%) were males and 97 (38.2%) females. The mean sodium values were 131.9±7.7 mmol/L in ABG and 132.3±7.1 mmol/L in CLA (p-value &lt;0.0001). The mean difference was 0.4 mmol/L. The mean potassium values were 3.9±1.0 mmol/L (ABG) and 4.2±0.9 mmol/L (CLA), {p-value&lt;0.0001}. The mean difference was 0.3 mmol/L. These differences were within the accepted range specified by the United States Clinical Laboratory Improvement Amendments. There were statistically significant strong positive correlations between the measurements of the two instruments r=0.78 for sodium and r=0.76 for potassium. The 95% LOA for sodium and potassium on both the instruments were -10.03 to 9.09 mmol/L and -1.49 to 0.97 mmol/L respectively, both wide and unacceptable. Conclusion: The arterial sodium and potassium measurements by BGA were not reliable in decision making in ED when compared to the venous serum by CLA as the 95% LOA was wide and unacceptable. Hence, sodium and potassium values by BGA alone might not be used as criteria for management without confirmation from venous serum values by CLA.

Asparaginase-induced pseudohyponatremia, a case-driven working strategy in pediatric patients

ABSTRACT Objectives When using indirect ion-selective electrode (ISE) methods, hypertriglyceridemia leads to pseudohyponatremia due to water displacement artifacts. Multiple strategies exist to minimize this interference. Our objective was to create a patient-friendly one-tube-fits-all testing setup without compromising the method robustness. Methods Four strategies were evaluated in a single patient with hypertriglyceridemia. Additionally, the interchangeability between the Cobas 8000 and ABL Flex was evaluated on samples (n = 2274) with different total protein (TP) concentrations. Finally, a proof-of-concept (n = 40) was performed by re-measuring the routine sample with the ABL90 Flex. Results ABL90 flex results and calculated sodium did not suffer from the presence of high triglyceride levels. We did not observe any significant differences between the three groups (P > 0.05) of sample types (arterial vs. venous plasma vs. venous whole blood after mixing up) nor for the analysers (Roche vs. ABL90 Flex). Passing–Bablok and Bland–Altman tests revealed interchangeability. Conclusion In future cases of hypertriglyceridemia, 1500 mg/dL will be used as a preliminary threshold for reliable sodium determination. Routine Li-heparin samples can be used for accurate sodium determination without any need for extra arterial or venous blood gas tubes, offering a patient-friendly test setup for similar cases.

Time-domain NIRS system based on supercontinuum light source and multi-wavelength detection: validation for tissue oxygenation studies.

We present and validate a multi-wavelength time-domain near-infrared spectroscopy (TD-NIRS) system that avoids switching wavelengths and instead exploits the full capability of a supercontinuum light source by emitting and acquiring signals for the whole chosen range of wavelengths. The system was designed for muscle and brain oxygenation monitoring in a clinical environment. A pulsed supercontinuum laser emits broadband light and each of two detection modules acquires the distributions of times of flight of photons (DTOFs) for 16 spectral channels (used width 12.5 nm / channel), providing a total of 32 DTOFs at up to 3 Hz. Two emitting fibers and two detection fiber bundles allow simultaneous measurements at two positions on the tissue or at two source-detector separations. Three established protocols (BIP, MEDPHOT, and nEUROPt) were used to quantitatively assess the system’s performance, including linearity, coupling, accuracy, and depth sensitivity. Measurements were performed on 32 homogeneous phantoms and two inhomogeneous phantoms (solid and liquid). Furthermore, measurements on two blood-lipid phantoms with a varied amount of blood and Intralipid provide the strongest validation for accurate tissue oximetry. The retrieved hemoglobin concentrations and oxygen saturation match well with the reference values that were obtained using a commercially available NIRS system (OxiplexTS) and a blood gas analyzer (ABL90 FLEX), except a discrepancy occurs for the lowest amount of Intralipid. In-vivo measurements on the forearm of three healthy volunteers during arterial (250 mmHg) and venous (60 mmHg) cuff occlusions provide an example of tissue monitoring during the expected hemodynamic changes that follow previously well-described physiologies. All results, including quantitative parameters, can be compared to other systems that report similar tests. Overall, the presented TD-NIRS system has an exemplary performance evaluated with state-of-the-art performance assessment methods.

Abstract 41: Changes In Renal Oxygen Consumption With High-salt Diet Differ Between Sprague Dawley And Dahl Salt Sensitive Rats.

It has appeared evident that blood flow to the renal cortex which is required for glomerular filtration far exceeds the delivery of O 2 required for tubular metabolic needs. Yet, the metabolic needs of kidneys are second only to the heart per gram tissue and changes in O 2 extraction and utilization have not been directly measured in face of enhanced workloads such those imposed by high salt (HS) diets. We have developed techniques enabling continuous 24 hr/d monitoring of renal blood flow (RBF; Transonic flow probe) together with blood pressure (BP, 24hr/d) and intermittent sampling of arterial and renal venous blood over 21 days. O 2 content (mL/dL) was determined as 1.31 х Hemoglobin (Hb) (g/dL) х HbO 2 (%) + 0.003 х PaO 2 (mmHg); O 2 consumption (ml/min) was determined as RBF (ml/min) х (arterial-renal venous O 2 content difference). Sprague Dawley rats (SD; n=7; 10 wk age) were compared to Dahl salt-sensitive (SS; n=6; 8 wk age) rats fed 0.4% NaCl and during the 21 days of 4.0% NaCl (HS) diet. Beginning 7 days following surgery, RBF and BP were recorded 24 hr/day, and arterial and renal venous blood sampled for determination of blood gases (ABL800 FLEX radiometer) at 7, 14 and 21 of the HS diet. Average 24 hr mean BP of SD rats increased with the HS diet from 111±2 to 119±5 mmHg and SS rats rose from 121±5 to 155±9 mmHg (p&lt;0.05); average 24 hr RBF of SD rats rose from 9.2±0.6 to 11.7 + 0.6 ml/min (p&lt;0.05) while SS rats exhibited little change (7.0±0.6 to 7.0 + 0.9). RBF when expressed per gram kidney weight (gkw; determined in separate groups of rats) remained unchanged in both SD and SS rats in response to the HS diet. SS rats exhibited lower levels of RBF gkw than SD rats (p&lt;0.05). Expressed either as absolute values or gkw, O 2 extraction and consumption was increased significantly in SD rats but not SS rats fed the HS diet. The results of the study indicate that despite high levels of RBF per tissue weight, increased metabolic work imposed by a HS diet resulted in a significant increase of RBF, O 2 extraction and consumption in normal rats. In contrast, SS rats exhibited lower levels of RBF but failed to increase either O 2 delivery or extraction. This failure may contribute importantly to altered metabolic substrate utilization in SS rats fed a HS diet, progression of ischemic related injury and hypertension.