Lactate Scout Research Articles

Comparison of lactate measurements from earlobe and fingertip capillary blood using Biosen S-Line and lactate scout analyzers.

This study aimed to compare variations between the earlobe and fingertip sampling sites in exercises dominated by upper body muscle exertion. It also sought to investigate capillary blood lactate differences between Lactate Scout 4 (LS4) and a bench-top analyzer (Biosen S-Line analyzer, BSL) during Double Poling. Blood samples were collected from the earlobe and fingertip immediately before exercise, at the end of each of five stages, and at 1-, 3-, 5-, and 7-min post-exercise. Forty healthy university students participated as volunteers. During the study, they performed double poling on a ski ergometer with progressively increasing load. Lactate levels were measured using both the BSL and LS4 analyzers. Fingertip Bla values were significantly higher than earlobe values, with a mean bias of -0.66mmol/L, reaching -0.86mmol/L in the 4-8mmol/L range. At the earlobe, the highest CCC between BSL and LS4-a was 0.84 (> 8mmol/L), and for BSL and LS4-b, it was 0.85 (> 8mmol/L). At the fingertip, the highest CCC between BSL and LS4-c was 0.68 (> 8mmol/L), and for BSL and LS4-d, it was 0.52 (> 8mmol/L). Comparing LS4-a and LS4-b at the earlobe, the highest CCC was 0.83 (0-4mmol/L). At the fingertip, comparing LS4-c and LS4-d, the highest CCC was 0.68 (> 8mmol/L). Blood lactate concentrations are higher at the fingertip than the earlobe during SkiErg double poling. The LS4 is less reliable, especially at the fingertip, so using the earlobe with the BSL analyzer is recommended for accurate measurements.

Precision and accuracy of four handheld blood lactate analyzers across low to high exercise intensities.

To evaluate the precision and accuracy in measured blood lactate concentrations among four commonly used handheld lactate analyzers compared to two stationary analyzers. Venous blood samples were taken at exercise intensities ranging from low to high. The blood lactate concentration was measured simultaneously with four pairs of handheld lactate analyzers (two new units of each brand: Lactate Plus, Lactate Pro2, Lactate Scout 4, and TaiDoc TD-4289), and compared with two stationary analyzers (Biosen C-Line and YSI Sport 1500). Measurements were repeated for a range of blood lactate concentrations (measured with Biosen) from 0.88 to 4.89mM with a median difference between measurements of 0.10 mM. The mean relative differences to the Biosen analyzer were 7% (Plus), 7% (Pro), 10% (Scout), 42% (Tai), and 32% (Ysi). The residual standard errors after linear regression against Biosen were 0.18 mM (Plus), 0.20 mM (Pro), 0.22 mM (Scout), 0.15 mM (Tai), and 0.06 mM (Ysi). Accordingly, a blood lactate concentration of 3mM measured with Biosen yielded 95% prediction intervals that were 0.72 mM (Plus), 0.80 mM (Pro), 0.87 mM (Scout), 0.60 mM (Tai), and 0.23 mM (Ysi) wide. Compared to our two stationary analyzers, the precision of the four handheld lactate analyzers evaluated in this study was poor. Among the four, Tai was the most precise; however, this analyzer had low accuracy with a substantial mean difference to the reference analyzer.

Transcranial magnetic stimulation in the assessment of acupuncture effect on exercise-induced fatigue.

Acupuncture as a traditional Chinese medicine therapy relies on unique theories to alleviate fatigue. The aim of this study is to evaluate the effect of acupuncture on exercise-induced fatigue utilizing transcranial magnetic stimulation (TMS). A total of 20 participants with regular exercise habits were recruited for this study. All participants were randomly assigned to receive either acupuncture or sham acupuncture intervention for exercise-induced fatigue. TMS and a heart rate monitor were used to measure the amplitude and latency of motor evoked potential (MEP) as well as heart rate every 5min over a 30-min period. The blood lactic acid (BLA) levels were measured using Lactate Scout+ at baseline, 0min, and 30min after fatigue. Two-way repeated measures analysis of variance was utilized to compare the differences between the effects of acupuncture method and time. Bonferroni post hoc tests were conducted to compare specific differences. Statistical significance was set at p<.05. Interaction effect was observed between acupuncture method and time effect in terms of amplitude (F(1, 38)=5.40, p<.001, η2=0.12) and latency (F(1, 38)=3.78, p=.008, η2=.09) of MEP. The application of acupuncture can promote the recovery of heart rate especially at 30min (p<.05), but which seem insufficient to generate significant difference in BLA (F(1, 38)=0.067, p=.797, η2=0.002). Acupuncture can promote the increase of MEP amplitude, shorten MEP latency, and restore heart rate. Preliminary findings provide novel insights for individuals with exercise habits to alleviate fatigue and enhance sports performance.

The effect of caffeine on running performance in performance triathletes

Background and purpose In an endurance sport such as triathlon, coaches at the elite level strive to select an appropriate nutritional strategy prior to performance in addition to optimizing the training process. Based on this, the research in question was designed with the aim to verify the effect of caffeine on the running performance of performance triathletes during the preparation period. Purpose is to determine the effect of caffeine on running performance in triathletes. Material and methods The study sample consisted of 8 performance triathletes from the TRIAN club of ŠK UMB Banská Bystrica, whose age was 16.7 ± 0.67 years. Diagnostics were run on InSPORTline Condi T6000i treadmill with the aim of detecting lactate and blood sugar levels (mmol/l) before the performance and within 10 seconds after the performance. The blood lactate level was detected with the portable device Lactate Scout+ and the blood glucose level was measured with the Wellion CALLA light glucose meter. The running pace at which the participants performed the test was at anaerobic threshold and they attempted to cover a distance of 1,500 m at a constant incline of 3%. The testing took place 1 time per week in the morning hours (08:00-08:30). On the second day after the initial testing from 01.03.2023 to 14.03.2023, the participants started taking placebo (magnesii lactas) on a daily basis in form of capsules. The participants took 2 capsules (200 mg magnesium) which they consumed with 200 mL of water 45 to 60 minutes before each morning workout/test. This was followed by the administration of caffeine capsules, which they consumed for an additional 2 weeks from 03.15.2023 to 03.28.2023. The participants consumed caffeine capsules at 5 mg/kg body weight 45 to 60 minutes before each morning workout/test. The intervention programme lasted 5 weeks. Results When administering caffeine capsules at a dose of 5 mg/kg body weight, there was a significant reduction of approximately 26% in the average blood lactate level of the participants after the 1,500 m run. The participants' mean blood glucose levels increased by approximately 4.9% after the 1500 m run. Conclusions Based on the results we can claim that for ergogenic effects on performance we recommend supplementing with 5mg/kg body weight of caffeine approximately 45 to 60 minutes before training.

Genetic and Physiological Predictors of Bioenergetic Adaptation Skeletal Muscles in Athletes of Cyclic Sports

When performing maximum loads, an important criterion for assessing prospects is the achievement of the best result with the least metabolic changes in the body of athletes, which indicates the possibility of further increasing physical performance. The study of the mechanisms of energy supply and the reaction of body systems when testing performance under special conditions is one of the important conditions for the development of additional biochemical criteria for assessing the prospects of athletes. Purpose: To study genetic and physiological predictors of bioenergetic adaptation of skeletal muscles in athletes of cyclic sports. Methods: 76 athletes of cyclic sports (speed skating, running disciplines in track-and-field) of European origin who lived in the Southern Urals region took part in the study. The average age of the study participants was 22.1 ± 2.5 y.o. Experience in sports was at least 5 years. We used the Step One Real-Time PCR System (Applied Biosystems, USA) device for real-time polymerase chain reaction. The study of bio-energetic indicators of athletes' physical performance was carried out using the bicycle ergometry method (test with maximum load). Biochemical studies were carried out using a Lactate Scout Plus lactometer. Results: Significant differences were found in the ΔLa (%) indicator: in athletes with a dominant homozygous genotype R/R, lactate clearance during a 10-minute rest after performing a bicycle ergometer load is statistically significantly higher than in athletes with a recessive homozygous genotype X/X (20.14±12.74%, versus 11.11±3.12%; p&lt;0.05). The major allele C (R) was associated with moderate and high lactate clearance (OR = 2.25 [95% CI: 0.99 – 5.11] and OR = 2.24 [95% CI: 0.91 – 5.51], respectively). At the same time, a statistically significant association was identified between the minor allele T(X) and the homozygous genotype TT (XX) with low lactate clearance (OR = 12.14 [95% CI: 1.30 – 13.55]). High values of lactate clearance indicate the utilization of lactate from peripheral blood and more efficient recovery processes in carriers of the major allele C (R). Conclusions: lactate clearance during a 10-minute rest period after a bicycle ergometer test with maximum load and DNA profiling of the ACTN3 gene rs1815739 can be recommended as significant physiological and genetic predictors of bioenergetic adaptation of skeletal muscles in cyclical sports athletes of Caucasian origin in the Southern Urals.

Monitoring methaemoglobinaemia in birds using 5μL of whole blood.

Methaemoglobin (MetHb) forming compounds such as para-aminopropiophenone (PAPP) and sodium nitrite (NaNO2) have recently been adopted for the lethal control of a range of invasive carnivores and mustelids. Determining the relative hazard of these compounds to non-target bird species is an important component of ecological risks evaluation. Problematically, some potential non-target bird species may be as small as 10 g in body mass, thus placing limitations on blood volumes that can be routinely sampled. Accordingly, we developed methods to quantify markers of increasing methaemoglobinaemia at their point of collection that required only 5 μL of whole blood. A 3 μL blood aliquot is pipetted into a plastic micro-cuvette and placed in a custom made holder optically coupled to the Ocean Optics spectrometer, enabling absorbance for oxyhaemoglobin (HbO: 575 nm) and MetHb (630 nm) to be determined. Haemoglobin (HbFe2+), packed cell volume (PCV) and lactate (LAC) data were generated from the remaining 2 μL aliquot apportioned to biosensor strips for the Cera-Check® and Lactate Scout® point-of-care devices. After oral doses of PAPP, a methaemoglobinaemia absorbance index (MAI = absorbance 575 nm-absorbance 630 nm) was strongly and significantly associated with dose-dependent declines in HbFe2+ in 9 bird species. Quantifying dose-dependent responses to MetHb-forming agents at the point of sample collection avoids analytical and storage artifacts arising from sample degradation that appears to be a much greater problem in avian blood compared to mammalian blood.

Sex-related differences in perceptual indices, serum cortisol and blood lactate responses to endurance exertion in competitive male and female athletes in a field setting

Background: Boxing requires very high aerobic fitness from male and female practitioners, therefore, endurance exercises play an important role in the preparation to competition. One of the way for rating of the state of demanded physical adaptation is monitoring of biological responses to endurance training units. The aim of the study was to examine psycho-hormonal responses to a 10km cross-country run in male and female boxers. Material and methods: Twenty-four amateur adult boxers, 12 women and 12 men, of various weight categories, excluding heavyweight athletes, performed field a 10km run. Capillary blood was sampled in the morning at 8:00, 5 minutes prior to the run (11:00 am), and within 5 minutes after exercise. Plasma cortisol concentration (C) was determined using a commercial ELISA kit (IBL, GERMANY). Post-exercise blood lactate was determined with a Lactate Scout analyzer. Pre-run anticipatory stress (AS) was estimated on a numerical scale of 1 to 10 points, with the same tool used to measure the rating of perceived exertion (RPE). Results: Morning plasma cortisol levels in females (54082 nM) and males (52073 nM) did not differ significantly but the pre-and post-run levels were higher in females. Furthermore, males rather than females showed lower pre-exercise compared to post-exercise C levels, meaning that blood lactate level was significantly higher in males (6.31.1 mM) compared to that in females (5.40.7 mM). There were no significant differences between the sexes for AS and RPE. However, both perceptual parameters were slightly higher in females. Conclusion: Based on blood cortisol measurements and perceptual parameters it can be concluded that the psychophysiological cost of exercise is higher in female athletes, even in the case of non-competitive exercise.

The impact of reaching the anaerobic threshold on some kinematic variables related to the accuracy of shooting the penalty kick among footballers

The aim of this study was to identify the correlation of the kinematic variables in the accuracy of shooting the penalty kick among footballers before and after reaching the anaerobic threshold, and also to identify the impact of reaching the anaerobic threshold on some kinematic variables related to the accuracy of shooting the penalty kick among football players. We used the experimental approach using the divided goal to determine the accuracy extent of shooting the penalty kick in addition to Cunningham and Faulkner Anaerobic Treadmill Test. The study sample consisted of 12 football players from the Jordanian Professional Football League for the year 2021, who are specialized in performing penalty kicks in their clubs. Their average age was 25.1± 4.1 years, average weight 71±2.2 kg and average foot weight 10.9±1.6. The study used Canon Eos 80D cameras, lactate Scout Cortex device and Kinovea 0.8.15 software to analyze the performance. The data was processed through the Statistical Package for the Social Sciences (SPSS). Our study showed that there is a statistically significant relationship at α = 0.05 of the kinematic variables before and after the player reaches the anaerobic threshold with the accuracy of shooting the penalty kick. The results also revealed that there is a statistically significant negative impact at α = 0.05 for reaching the anaerobic threshold on some kinematic variables related to the accuracy of shooting the penalty kick among football players. In conclusion, the kinematic variables of the study and the accuracy of shooting the penalty kick were negatively affected by reaching the anaerobic threshold at a level that exceeds 4.2 mmol/L.

Comparaison de la mesure des lactates au cordon par des appareils portatifs ayant l’habilitation pour une utilisation pendant le travail avec un appareil de référence

ObjectiveTo compare two portable lactate devices, Lactate Scout and StatStrip Xpress, to a laboratory reference device by assessing the concordance of cord blood lactate values at birth. MethodsWe conducted a single-center prospective validation study in a level 3 maternity hospital. For all cord samples taken at birth, we analyzed lactates on the reference device (GEM4000®) and on two portable devices Lactate Scout and StatStrip Xpress. We compared the lactate values from each of the two handheld devices to the reference device. ResultsA total of 101 samples were collected. Each was analyzed by all three machines. The average lactate value obtained by the different machines was 3.7mmol/L. The mean difference between the Lactate Scout and GEM4000® apparatus was 0.0mmol/L±0.8mmol/L. Between these two devices at lactate threshold of 4.8mmol/L, the negative predictive value was 96,2% (76/79) and the area under the curve was 0.98 (95% CI 0.96–1]. The mean difference between StatStrip Xpress and GEM4000® was 0.1mmol/L±0.7mmol/L. Between these two devices at the lactate threshold of 4.8mmol/L, the negative predictive value was 97,4% (76/78) and the area under the curve was 0.95 (95% CI 0.86–1). ConclusionThere is a good correlation between the lactates obtained by the reference device and the two portable devices Lactate Scout and StatStrip Xpress.

Cardiorespiratory fitness and cognition in healthy elderly and MCI patients

AbstractBackgroundCurrent research indicates a positive impact of physical activity on healthy ageing, on brain plasticity and on the risk for dementia. Furthermore, several epidemiological, cross‐sectional and interventional studies have shown that cardiorespiratory fitness is associated with cognitive performance, especially regarding executive functions.MethodHere, we investigated the relationship between cardiorespiratory fitness and cognition in both healthy elderly (n=33; age: 68.8 ± 6.9) and in patients with mild cognitive impairment (MCI; n=27, age: 70.8 ± 6.1). Cardiorespiratory fitness was assessed using bicycle spiroergometry (cosmos torqualizer 600ef med; Germany) with an incremental step test. To determine the metabolic status, capillary blood samples were taken from the ear at rest (baseline), after each step and one, three and five minutes after the incremental step test was finished. The lactate concentration was measured with lactate scout sensors (SensLab GmbH Leipzig, Germany). Cognitive abilities were measured with the extended CERAD plus neuropsychological test battery (including Trial making test &amp; verbal fluency S words).ResultStatistical analysis revealed significant between group differences in cognitive functions (e.g. MMSE, p&lt;.001 TMT‐A, p&lt;.001), but no significant differences in cardiorespiratory fitness (e.g. VO2peak, Wpeak, lactate). Furthermore, correlation analysis showed a significant correlation between VO2peak and MMSE in healthy elderly (p=.029, r=‐0.333)), but not in MCI patients (p=.317, r=‐0.096).ConclusionOur results indicate no differences in cardiorespiratory fitness between healthy elderly and MCI patients. However, cardiorespiratory fitness is associated with general cognition in healthy elderly. Why this correlation was not seen in MCI patients needs to be assessed in more detail in future research.

The Effects of Ground and Treadmill Running on Energy Metabolism and Muscle Contractile Properties: A Randomized Cross-Over Study

PurposeThis study aimed to compare the effects of ground and treadmill running on energy metabolism and muscle contractile properties, providing a basis for the general public to choose running venues.MethodsTen male college students (age, 20.10 ± 1.53 years; height, 176.20 ± 5.49 cm; weight, 72.14 ± 8.25 kg; body fat percent, 12.41% ± 4.65%) were recruited in this study. Energy expenditure (EE) was measured using the accelerometer (GT9X) combined with specific estimation equations. Average heart rate (HR) was measured using a heart rate band (Polar). Muscle contractile properties were assessed by measuring muscle displacement (Dm) and contraction velocity (Vc) using tensiomyography (TMG-S1). Blood glucose (Glu) and lactate (Lac) were measured by portable devices (eB-G and Lactate Scout). The running speed was 9 km/h and the duration was 25 min. Two-way ANOVA (protocol × time) was used to analyze the effect of running protocols on energy metabolism and muscle contractile properties.ResultsEE of treadmill running was significantly higher than EE of ground running (protocol main effect, P < 0.001), and HR of treadmill running was significantly higher than that of ground running in the first testing time (protocol simple effect, P = 0.026; protocol × time interaction P = 0.043). The decrease in Dm of the rectus femoris after treadmill running was significantly higher than that of ground running (protocol main effect, P = 0.009). The interaction of different running protocols and testing times on Lac was significant (P = 0.025), but all results of the simple effects analysis were not statistically significant (P > 0.05).ConclusionOur study found a difference in energy expenditure between treadmill and ground running at 9 km/h with duration of 25 min. In addition, treadmills are more likely to cause a decrease in muscle displacement distance of the rectus femoris measured after exercise than ground running. Future studies are needed to further investigate whether the differences are induced by internal metabolism or the environmental conditions of running.

Correlation between L-Lactate Concentrations in Beef Cattle, Obtained Using a Hand-Held Lactate Analyzer and a Lactate Assay Colorimetric Kit.

Simple SummaryLactate is a metabolite used in animal research as an indicator of muscle fatigue; therefore, it has been used as an indicator of cattle response to long distance transportation. The aim of this study was to assess the relationship of L-lactate concentrations measured using a Lactate Scout+ hand-held analyzer and a traditional lactate assay colorimetric kit. Blood samples were collected from 96 steers prior to loading and after 36 h of transportation, and prior to reloading and after an additional 4 h of road transportation, and on d 1, 2, 3, 5, 14, and 28 after transport. The Lactate Scout+ hand-held analyzer strip was dipped in blood at the time of sampling, while blood samples were collected into sodium fluoride tubes for use in the colorimetric analysis. Correlations were calculated to assess the strength of the relationship between the L-lactate concentrations measured between methods. The strength of the correlation and the level of statistical significance varied over the observed time points, while the correlation for the pooled data was weak. Based on the low strength of the correlation, the Lactate Scout+ analyzer is not a suitable alternative to a colorimetric assay for measuring L-lactate in transported cattle.Lactate is a product of anaerobic glycolysis, used in animal research as an indicator of muscle fatigue. Therefore, it has been used as an indicator of cattle response to long distance transportation. The aim of this study was to assess the relationship of L-lactate concentrations measured using a Lactate Scout+ analyzer and a traditional lactate assay colorimetric kit. Blood samples were collected by venipuncture from 96 steers (Black or Red Angus × Hereford/Simmental and Black or Red Angus × Charolais; 247 ± 38.2 kg BW) prior to loading (LO1) and after 36 h of transport, and prior to reloading and after an additional 4 h of road transportation, and on d 1, 2, 3, 5, 14, and 28 after transport. The Lactate Scout+ analyzer strip was dipped in blood at the time of sampling, while blood samples were collected into sodium fluoride tubes for use in the colorimetric analysis. Pearson correlations were calculated to assess the strength of the relationship between the experimental methods for the quantification of L-lactate concentrations. The magnitude and direction of the correlation, and the level of statistical significance varied over the observed time points, ranging from r = −0.03 (p = 0.75; LO1) to r = 0.75 (p < 0.0001; d 3). The correlation for the pooled data was weak but statistically significant (r = 0.33, p < 0.0001). Based on the low magnitude of the correlation due to variability across sampling time points in this study, the Lactate Scout+ analyzer is not a suitable alternative to a lab-based assay (considered the gold standard) for measuring L-lactate in transported cattle.

PSVII-3 Correlations between L-lactate concentrations obtained using a handheld lactate analyser and a lactate assay colorimetric kit in beef cattle transported by road

Abstract Blood metabolites are used to assess a variety of animal conditions for veterinary diagnosis and research. Concentration of metabolites in blood can be measured using a commercially-available lab-based assay or in real-time using a handheld device developed to be more time- and cost-effective than the lab-based method. Lactate is a product of anaerobic glycolysis, used in animal research as an indicator of muscle fatigue. Therefore, it has been used as an indicator of cattle response to long distance transportation. The aim of this study was to assess the relationship of L-lactate concentrations measured using a Lactate Scout+ analyzer (Lactate Scout, EFK Diagnostics, Barleben, Germany) and a lactate assay colorimetric kit (Lactate Assay Kit, Cell Biolabs Inc., San Diego, CA). Blood samples were collected by venipuncture from 96 steers (245 ± 35.7 kg BW) prior to (L1) and after 36 h, and prior to and after an additional 4 h of road transportation, and on d 1, 2, 3, 5, 14, and 28 after transport. The Lactate Scout+ analyzer strip was dipped in blood at the time of sampling, while blood samples were collected into sodium fluoride tubes for use in colorimetric analysis. Pearson correlations were calculated to determine the relationship between the experimental methods for the quantification of L-lactate concentrations. The strengths and levels of statistical significance of the correlation varied over the observed time points, r = -0.03, P = 0.75 (L1) to r = 0.75, P = &amp;lt; 0.0001 (d 3). The correlation for the pooled data was weak but statistically significant (r = 0.33, P &amp;lt; 0.001). Based on the experimental results, the Lactate Scout+ analyzer is not a suitable alternative to a lab-based assay for measuring L-lactate in transported cattle, due to variability across sampling time points and weak correlation with the traditional enzymatic method.

Validation Of The Humon Hex Lactate Threshold Estimate

Fitness trackers track a wide range of fitness and physiological metrics, including muscle oxygen saturation and lactate threshold (LT). The Humon Hex (HH) is a low-cost wearable device that uses continuous-wave near-infrared spectroscopy (NIRS) to determine muscle oxygen saturation. The HH is unique in its ability to estimate LT based on muscle oxygen saturation during a threshold test. PURPOSE: The purpose of this study was to determine the validity and accuracy of predicting LT from continuous-wave NIRS compared to lab-based measurements. METHODS: 15 healthy, recreational runners (6 male, 9 female, 26.1 ± 6.4yrs, 67.9 ± 16.3kg, 173.3 ± 9.5cm, 31.6 ± 21.5km/week) participated in a single threshold test on a treadmill. The protocol was dictated by the HH device (“Threshold Test” in the app) and involved increasing treadmill velocity by 0.22 m/s (0.5 mph) every 3 min until volitional exhaustion. At the end of each stage, participants would straddle the treadmill while researchers collected and analyzed the blood lactate levels using a Lactate Scout portable lactate analyzer (Lactate.com). The HH LT estimate was provided by the Humon website. Blood lactate levels were recorded and graphed, and LT was derived by identifying the point immediately prior to where lactate levels had a greater than 1mmol/L jump from the previous stage that also placed the total lactate concentration above 4mmol/L. A 2-tailed, paired t-test, mean absolute percentage error (MAPE), single measures Intraclass Correlations (ICC), and Bland-Altman analysis with accompanying bias and Limits of Agreement were performed, calculated and plotted. RESULTS: There was no difference between the HH estimated LT velocity compared to the lab-based methods (12.5 ± 2.0km and 12.7 ± 1.3km/hr, respectively). There was a MAPE of 9.00% and an ICC of 0.652 with a 95% confidence interval of -0.222 to 0.869 (F(15,15) = 4.546, p = 0.004) when comparing the variables. CONCLUSION: Although there was no difference between HH estimated LT velocity compared to laboratory testing, the MAPE was above 5% and ICC slightly below 0.7 with a significant relationship. This data suggests that the HH does not produce a completely valid estimate of LT compared to lab-based tests; however, it still may be useful in situations where laboratory testing may not be available or practical.

Point-of-Care, Cable Type Electrochemical Sensor with Ultrahigh Sensitivity for Detection of Metabolites in Human Perspiration

Point-of-Care, Cable Type Electrochemical Sensor with Ultrahigh Sensitivity for Detection of Metabolites in Human Perspiration

Agreement between capillary and venous lactate in emergency department patients: prospective observational study

ObjectivesCapillary blood lactate testing with handheld analysers has great advantages to reduce the time needed for clinical decisions, and for extended use in the prehospital setting. We investigated the agreement...

Handheld Point-of-Care Lactate Measurement at Admission Predicts Mortality in Ugandan Children Hospitalized with Pneumonia: A Prospective Cohort Study.

Globally, pneumonia is the leading cause of death among children younger than 5 years old, with most deaths occurring in low-income countries. Rapid bedside tools to assist practitioners to accurately triage and risk-stratify these patients may improve clinical care and patient outcomes. We conducted a prospective cohort study of children with pneumonia admitted to two Ugandan hospitals to examine the predictive value of a single point-of-care lactate measurement using a commercially available handheld device, the Lactate Scout Analyzer. One hundred and fifty-five children were included, 90 (58%) male, with a median (interquartile range [IQR]) age of 11 (1.4-20) months. One hundred and twenty-five (81%) patients had chest indrawing, 133 (86%) were hypoxemic, and 75 (68%) had a chest x-ray abnormality. In-hospital mortality was 22/155 (14%). Median (IQR) admission lactate level was 2.4 (1.8-3.6) mmol/L among children who survived versus 7.2 (2.6-9.7) mmol/L among those who died (P < 0.001). Lactate was a better prognostic marker of mortality (area under receiver operator characteristic 0.76, 95% confidence interval: 0.69-0.87, P ≤ 0.001), than any single clinical sign or composite clinical risk score. Lactate level at admission of < 2.0, 2.0-4.0, and > 4.0 mmol/L accurately risk-stratified children, with 5-day mortality of 2%, 11% and 26%, respectively (P < 0.001). Slow lactate clearance also predicted subsequent mortality in children with repeated lactate measurements. Hand-held lactate measurement is a clinically informative and convenient tool in low-resource settings for triage and risk stratification of pediatric pneumonia.

Capillary and venous point-of-care testing of lactate concentrations in the emergency department: a prospective observational study

BackgroundHyperlactatemia is a sensitive marker for early identification of patients who are critically ill. Rapid capillary lactate measurement using a handheld device can hasten the identification of patients at risk. We aimed to compare capillary lactate with venous blood lactate assessed using a blood gas analyser in the emergency department. MethodsThis was a prospective observational study of patients presenting to the emergency department in Hong Kong SAR. Venous and fingertip capillary blood samples were collected for lactate analysis. Venous lactate concentrations measured using a point-of-care blood gas analyser was used as a reference method (VL-Ref). Capillary lactate concentrations were measured using two handheld analysers: (1) Nova StatStrip Xpress (CL-Nova); and (2) Lactate Scout+ (CL-Scout+). Venous lactate measurements were also done using two handheld analysers (VL-Nova and VL-Scout+). Bland-Altman analysis was used to determine the agreement between different methods of measurement. Ethics approval was obtained from the Institutional Review Board of the Chinese University of Hong Kong (CREC 2015.624). Written consent was obtained either from the patient or a relative in all cases. The study is registered with ClinicalTrials.gov (NCT02694887). FindingsBetween March and July, 2016, we recruited 240 patients (aged 18 years or older) who were triage category 3 (urgent) presenting to the emergency department. Of 240 patients (mean age 69·9 years; 54% men), lactate concentrations were in the range 0·70–5·38 mmol/L (mean 1·96mmol/L). 151 patients (63%) had lactate concentrations (VL-Ref) less than 2 mmol/L, and 89 patients (37%) had lactate concentrations of at least 2 mmol/L. The results of a Bland-Altman analysis showed that percentage of mean difference were −6·2% between VL-Ref and CL-Scout+, 29·9% between VL-Ref and CL-Nova, with 95% limits of agreement of −79·3 to 66·8% and −43·8 to 103·6%, respectively. Regarding venous blood lactate, the results showed bias values of 13% between VL-Ref and VL-Scout+, 55·3% between VL-Ref and VL-Nova, with limits of agreement being −23·9 to 49·9% and 20·7 to 90·0%, respectively. InterpretationAn overall low systemic bias were observed in CL-Scout+ (bias −6·2%) and VL-Scout+ (bias 13%), suggesting the potential clinical utility of the Scout+ handheld analyser. However, the wide range of limits of agreement implies poor precision of using fingertip capillary blood for lactate testing. Further studies are needed to validate the use of capillary lactate in emergency settings. FundingDirect Grant for Research, The Chinese University of Hong Kong.

Reliability of Lactate Scout Portable Analyzer in Agility Dogs During Multiple Measurements

Abstract The aim of this study was to evaluate the reliability of multiple measurements with Lactate Scout portable analyzer in dogs during treadmill exercise. Ten Border collies were involved in the study and blood samples were taken before, three times during and twice after the treadmill exercise. Lactate concentration was measured in duplicate, by Scout portable analyzer and the reference biochemical analyzer in the laboratory, and the obtained values were compared. There was a high and positive correlation between these two methods (r=0.96, p=0.003). The Lactate Scout analyzer reveals a high degree of agreement with the laboratory method and therefore can be valid for use in research of veterinary sports medicine and emergency veterinary medicine where multiple measurements of lactate concentrations are often needed.

Reliability of the Lactate Scout point-of-care instrument for the determination of blood L-lactate concentration in sheep.

Data on accuracy and precision of the Lactate Scout point-of-care (POC) analyzer in ovine medicine are lacking. The purpose of the study was to assess the reliability of the Lactate Scout in sheep. Fifty-seven sheep at varying ages with various diseases were included. Blood lactate concentration in samples collected from the jugular vein was measured immediately on the Lactate Scout. Plasma L-lactate concentration was measured by the Cobas autoanalyzer as the reference method. Data were subjected to Student's t-test, Passing-Bablok regression, and Bland-Altman plot analyses for comparison and assessment of accuracy, precision, and reliability. Plasma l-lactate concentration was consistently lower than blood L-lactate concentration (3.06 ± 0.24 vs 3.3 ± 0.3 mmol/L, P < .0001). There was a positive correlation between plasma and blood L-lactate concentrations (r = .98, P < .0001). The Lactate Scout had 99% accuracy and 98% precision with the reference method. Blood (Y) and plasma (X) L-lactate concentrations were fitted to Y = 0.28 + 1.00 · X, with a residual standard deviation of 0.31 and a negligible deviation from the identity line (P = .93). The bias was fitted to Y = 0.10 + 0.05 · X, with Sy.x of 0.44 (P < .07). The Lactate Scout has high accuracy and precision, with a negligible bias. It is a reliable POC analyzer to assess L-lactate concentration in ovine medicine.