Handheld Lactate Meter Research Articles

Comparison of plasma l-lactate between jugular and cephalic veins in healthy and systemically ill horses using a point-of-care device.

To compare plasma l-lactate (LAC) values between samples collected from jugular and cephalic venipuncture in healthy horses and systemically ill horses. Prospective, experimental study. Large animal university teaching hospital. Thirty healthy adult university-owned horses and 43 client-owned horses presenting to the large animal hospital for elective surgical procedures or for emergent medical evaluation of systemic illness. Blood samples were collected from the jugular vein (JV) and cephalic vein (CV) and placed in EDTA blood tubes prior to any medical therapy. LAC values were obtained with a handheld lactate meter at the time of blood collection. LAC was higher in CV samples than JV samples in healthy horses (P<0.001); however, all values were within the normal reference range. Similarly, LAC was higher in CV samples than JV samples in systemically ill horses (P<0.001), but the median JV value was within normal reference range (1.9mmol/L [17.1mg/dL]), while the median CV value was outside the normal reference range (2.9mmol/L [26.1mg/dL]). The CV is an alternative venipuncture site for assessing plasma LAC if the JV is not accessible or to preserve the JV for subsequent catheterization. However, in ill horses, the CV value may be outside the reference range when the corresponding JV value would have been within the reference range.

Use of Lactate ProTM2 for measurement of fetal scalp blood lactate during labor – proposing new cutoffs for normality, preacidemia and acidemia: a cross-sectional study

Objective Measurement of fetal scalp blood lactate is a supplementary tool to cardiotocography in the case of a non-reassuring tracing. Several hand-held lactate meters have been launched, all with differentials in absolute values. Therefore, the reference intervals must be calculated for each device. The internationally accepted reference interval is based on measurement with Lactate ProTM with recently got out of production. The aim of this study was to propose cutoffs for normality, preacidemia, and acidemia in fetal scalp blood for Lactate ProTM2 based on the comparison of lactate values measured with Lactate ProTM and Lactate ProTM2. Design Seven hundred one fetal scalp blood samples were analyzed simultaneously. The conversion equations were retrieved from the linear regression model. On the basis of the cutoffs for Lactate ProTM cutoffs for Lactate ProTM2 were calculated. Results The conversion equations obtained were Lactate ProTM = −0.02 + 0.68 × Lactate ProTM2 (SD: −0.09–0.07 × Lactate ProTM2) and Lactate proTM2 (LP2) = 0.03 + 1.48 × Lactate ProTM (SD: 0.16 + 0.17 × Lactate ProTM). The correlation to umbilical arterial pH was identical for the two devices (r = −0.18), whereas the correlation to umbilical arterial lactate was better for Lactate ProTM than for Lactate ProTM2 (r = 0.38, respectively, r = 0.33). The correlation to umbilical arterial lactate was dependent on time from sampling to delivery. Conclusion Proposed reference values for Lactate ProTM2: scalp lactate <6.3 mmol/L = normal, no indication for intervention; 6.3–7.1 mmol/L = preacidemia, repeated testing has to be considered; > 7.1 mmol/L = acidemia, expedite delivery.

Assessment of a portable lactate meter for field use in the white rhinoceros (Ceratotherium simum).

Blood lactate is a predictor of mortality in critically ill humans and animals. Handheld lactate meters have the potential to be used in the field to evaluate the condition of severely injured rhinoceroses but have not been compared with laboratory-based methods. Agreement between a handheld lactate meter and a laboratory method was assessed, as was the stability of rhino blood lactate in the anticoagulant sodium fluoride/potassium oxalate (fluoride/oxalate). Blood samples were obtained from 53 white rhinos that had been immobilised for management reasons. Lactate was measured by means of a handheld meter using whole blood in heparin (WBHEP), whole blood in fluoride/oxalate (WBFO) and fluoride/oxalate plasma (PFO). Results were recorded in both blood (BL) and plasma (PL) modes and compared to an established laboratory method for measuring plasma lactate. To assess the stability of lactate over time, blood lactate in fluoride/oxalate was measured on the handheld meter at intervals for up to 91 h. Agreement was best using WBFO in PL mode, with small bias (−0.16), tight 95% limits of agreement (LOA) (−1.46, 1.14) and a Pc (95% CI) of 0.97 (0.92, 0.99). The agreement was improved for all sample types when using the PL mode compared to the blood lactate (BL) mode. Blood lactate was stable in fluoride/oxalate for 91 h, with a mean change from baseline of 0.15 (−0.178, 0.478) mmol/L (mean, 95% CI). The handheld meter was found to be suitable for field use in white rhinos but provided more reliable results with the device in PL mode. Furthermore, rhino blood lactate was found to be stable in fluoride/oxalate for as long as 3 days.

Prehospital Lactate Measurement by Emergency Medical Services in Patients Meeting Sepsis Criteria.

IntroductionWe aimed to pilot test the delivery of sepsis education to emergency medical services (EMS) providers and the feasibility of equipping them with temporal artery thermometers (TATs) and handheld lactate meters to aid in the prehospital recognition of sepsis.MethodsThis study used a convenience sample of prehospital patients meeting established criteria for sepsis. Paramedics received education on systemic inflammatory response syndrome (SIRS) criteria, were trained in the use of TATs and hand-held lactate meters, and enrolled patients who had a recent history of infection, met ≥ 2 SIRS criteria, and were being transported to a participating hospital. Blood lactate was measured by paramedics in the prehospital setting and again in the emergency department (ED) via usual care. Paramedics entered data using an online database accessible at the point of care.ResultsPrehospital lactate values obtained by paramedics ranged from 0.8 to 9.8 mmol/L, and an elevated lactate (i.e. ≥ 4.0) was documented in 13 of 112 enrolled patients (12%). The unadjusted correlation of prehospital and ED lactate values was 0.57 (p< 0.001). The median interval between paramedic assessment of blood lactate and the electronic posting of the ED-measured lactate value in the hospital record was 111 minutes. Overall, 91 patients (81%) were hospitalized after ED evaluation, 27 (24%) were ultimately diagnosed with sepsis, and 3 (3%) died during hospitalization. Subjects with elevated prehospital lactate were somewhat more likely to have been admitted to the intensive care unit (23% vs 15%) and to have been diagnosed with sepsis (38% vs 22%) than those with normal lactate levels, but these differences were not statistically significant.ConclusionIn this pilot, EMS use of a combination of objective SIRS criteria, subjective assessment of infection, and blood lactate measurements did not achieve a level of diagnostic accuracy for sepsis that would warrant hospital prenotification and committed resources at a receiving hospital based on EMS assessment alone. Nevertheless, this work provides an early model for increasing EMS awareness and the implementation of novel devices that may enhance the prehospital assessment for sepsis. Additional translational research studies with larger numbers of patients and more robust methods are needed.

Preliminary investigation of the area under the L-lactate concentration-time curve (LACArea) in critically ill equine neonates.

BackgroundA variety of measures of l‐lactate concentration ([LAC]) in the blood of critically ill neonatal foals have shown utility as prognostic indicators. These measures, evaluating either the severity of hyperlactatemia or the duration of exposure to hyperlactatemia, perform fairly well and have correctly classified 75–80% of foals examined in several studies. The area under the l‐lactate concentration versus time curve (LAC Area) encompasses both severity and duration of hyperlactatemia and should improve correct classification of patient survival.Hypothesis/Objectives LAC Area is larger in nonsurviving critically ill neonatal foals.AnimalsForty‐nine foals admitted for critical illness to 1 of 4 referral hospitals.MethodsWhole blood was obtained at admission and 6, 12, 18, and 24 hours after admission for measurement of l‐lactate using a handheld lactate meter. LAC Area was calculated for: admission–6, 6–12, 12–18, 18–24 hours, and admission–24 hours using the trapezoidal method and summing the 6‐hours interval areas to determine total 24 hours area. Differences between survivors and nonsurvivors were determined using robust regression and Kruskal–Wallis testing, P < .05.Results LAC Area was significantly larger in nonsurviving foals (n = 9) than in surviving foals (n = 40) at all time periods examined.Conclusions and Clinical ImportanceDifferences in LAC Area between surviving and nonsurviving critically ill neonatal foals are large and support further investigation of this method as an improved biomarker for survival in critically ill neonatal foals is indicated.

Validation of the handheld Lactate-Pro analyzer for measurement of blood L-lactate concentration in cattle.

Blood L-lactate concentration (LAC) can be used for various diagnostic purposes in cattle. As multiple handheld analyzers for LAC exist, it is important to validate their use in cattle in comparison with reference laboratory blood analyzers. The objectives of this study were to validate the handheld Lactate Pro meter (LacP) including reproducibility, and compare the measurements with the StatProfile (StatP) as a gold standard. In addition, diagnostic sensitivity and specificity, and the impact of HCT on LAC measured by both analyzers were assessed. A cohort of 64 cattle with acute medical and surgical conditions was studied. Whole blood samples in heparin lithium tubes were analyzed upon arrival with both StatP and LacP. Twenty-three samples were immediately retested to assess intra-assay coefficient of variation (CV). The HCT values were also recorded. The LAC using LacP was highly correlated with the StatP (r=0.9736 [95% confidence interval [CI]: 0.9562-0.9841]). The LacP underestimated LAC (mean difference:-0.9mmol/L, 95% CI:-3.1mmol/L to 1.3mmol/L). The intra-assay CV was excellent (4.77%). No significant correlation was observed between LacP or StatP and HCT (P=.39 and .09, respectively). Sensitivity and specificity for LacP were 91.7% (95% CI: 76.4-97.8%) and 100% (83.4-100%, cutoff of 4mmol/L), and 78.6% (58.5-90.9%) and 100% (87.0-100%, cutoff of 6mmol/L). The LacP handheld lactate meter can be used safely and reliably cow-side, although it underestimates LAC value when compared with a standard laboratory analyzer especially for LAC≥10.0mmol/L. The LAC value was not influenced by HCT in this study.

Evaluation of Three Handheld Lactate Meters for Measuring Hemolymph L-Lactate in Decapod Crustaceans

The aim of this study was to determine the reliability and accuracy of 3 commercially available handheld lactate meters when measuring hemolymph L-lactate in decapod crustaceans. The instruments tested were Accutrend Plus (AP), Lactate Scout (LS), and Lactate Plus (LP), and all models were tested in triplicate and compared with a commonly used enzymatic kit for L-lactate quantification (TB-kit). The Norway lobster Nephrops norwegicus and the European lobster Hommarus gammarus were used as model organisms, with emersion as an invoker of hemolymph L-lactate. Between-method comparisons were investigated by determining correlations (Pearson's r) and concordance (concordance correlation coefficient (CCC) and Bland-Altmand's 95% limit of agreement (95% LOA)) between handheld instruments and TB-kit. Within-instrument variation was tested by calculating the coefficient of variation (CV), and the average absolute deviation from the mean (AD). The within-instrument variation was low for all models (CV, 3.8–6.1%; AD, <0.3 mM), showing high reproducibility of technical replicates. A significant correlation with TB-kit was found for all handheld instruments (AP, r = 0.970; LS, r =; 0.956; LP, r = 0.950). For both AP and LS, there was a moderate and significant concordance with TB-kit (AP, CCC = 0.945; LS, CCC = 0.940). The mean difference from TB-kit was -1.42 mM (95% LOA,-4.50–1.66 mM) for AP and 1.19 mM (95% LOA,-3.13–5.51 mM) for LP. Emersion experiments with the European lobster showed that AP and LS were in line with TB-kit in terms of detecting differences in L-lactate levels between groups of animals. As a result of the high frequency of error readings from LP, this instrument was not considered reliable when measuring L-lactate in decapod crustaceans. In conclusion the handheld instruments AP and LS are found to be reliable instruments when measuring hemolymph L-lactate in decapod crustaceans. Comparison of results from different methods should be avoided, and in cases when accurate absolute measurement of L-lactate is needed, methods allowing for greater accuracy and resolution should be used.

Accuracy of a hand-held lactate meter in measuring umbilical cord blood lactate at all lactate levels

Objective: Fetal scalp lactate has largely replaced pH analysis to assess intrapartum hypoxia. Many obstetrics units use hand-held lactate meters to measure umbilical blood because of its affordability and ease of use. We sought to investigate the agreement of Lactate ProTM with a reference method blood gas analyser and to determine its usefulness with a recommended cutoff value of 4.8 mmol/L. Methods: Prospective study carried out at a tertiary institution where 237 arterial and 233 venous samples from umbilical cords of 16 elective caesarean and 285 emergency deliveries were measured using Lactate ProTM and ABL735 Sesries Acid-Base analyser. Limits of agreement were analysed using Bland-Altman plots. Results: Lactate ProTM differentiated fewer deliveries as “high risk” (≥4.8 mmol/L) and more as “low risk” (TM) were –1.46 - 0.97 mmol/L for arterial lactate levels arterial lactate levels ≥ 4.8 mmol/L. Conclusion: There was a poorer agreement between the two devices at higher lactate values. Lactate ProTM underestimates by up to 3.2 mmol/L; a 4.8 mmol/L reading may actually signify a lactate level of 8.0 mmol/L, indicating severe metabolic acidosis. We caution the use of this device in assessing fetal lactate levels.

A pilot study to determine the feasibility of collecting amniotic fluid samples from women during labour and measuring amniotic fluid lactate at point of care

BackgroundThe level of lactate in amniotic fluid may provide useful clinical information when assessing progress of a woman’s labour and if so, a rapid, reliable method to assess amniotic fluid lactate is required in order to be clinically relevant. However, measuring lactate levels in amniotic fluid, using portable, handheld lactate meters may be less accurate than reference laboratory instruments designed to measure lactate levels in aqueous solutions. Prior to conducting a large study, we assessed recruitment, consent and sampling procedures, and the accuracy of a handheld lactate meter to measure lactate in amniotic fluid. We compared amniotic fluid lactate results obtained using the hand held Lactate Pro (Arkray) to results obtained using reference laboratory methods ABX Pentra 400 (Horiba).ResultsWe recruited 35 nulliparous women during their antenatal hospital visits and tested amniotic fluid samples collected from 20 labouring women. The handheld Lactate Pro meter was found accurate from 9–20 mmol/L with a Passing & Bablok regression of y = 0.18 + 0.97x (95% CI 0.76–1.45). Amniotic fluid lactate results remained reliable in the presence of potential contaminants commonly encountered during labour; obstetric lubricant, blood and meconium.ConclusionThe measurement of amniotic fluid lactate using the Lactate Pro meter was reliable compared to reference laboratory methods for measuring lactate levels in amniotic fluid. The pilot study enabled the refinement of information, recruitment, consenting and sampling procedures prior to commencing a large cohort study.

A new method for rapid measurement of lactate in fetal and neonatal blood.

A prospective trial to determine the accuracy and precision of the Boehringer Mannheim Accusport handheld lactate meter in measuring plasma lactate levels in umbilical cord blood and neonatal blood microsamples was performed in the labour ward and the neonatal intensive care unit of the NepeanHospital. Specimens were collected from the umbilical artery of 160 consecutive deliveries covering gestations from 26 to 42 weeks, and from 110 umbilical artery catheters covering a range of gestations from 26 to 41 weeks. Serum was also obtained from an exchange transfusion for coefficient of variation analysis. Blood was simultaneously tested for lactic acid concentration on the Boehringer Mannheim (BM) Accusport held lactate meter and the Radiometer ABL 625 blood-gas machine. Clinical data from the mother and baby were recorded together with the full blood-gas analysis for comparison with the lactate measures. Coefficients of variation for the BM Accusport lactate meter were established by a further 120 samples of plasma lactate at 6 concentrations from 1 to 20 mmol/L. The stability of measurements with the BM lactate meter over a wide range of temperatures was ascertained by repeated sampling of known concentrations of plasma lactate from 0.5 degrees C to 37 degrees C. The BM Accusport lactate meter was found to be accurate from 1 mmol/L to 20 mmol/L with a Passing Bablok regression line y = 0.004 + 0.915 x (95% CI of slope of 0.889 to 0.946 and intercept -0.138 to 0.094) for whole blood, and y = 0.200 + 1.000 x (95% CI of slope 0.989 to 1.018 and intercept 0.080 to 0.222) for plasma. Between run coefficient of variation (CV) was calculated to be 1.23% to 5.53% over the clinically significant range (2.2-19.3 mmol/L). The BM lactate meter was accurate from 5 to 37 degrees C. At 0.5 degrees C the BM lactate meter significantly underestimated the plasma lactate concentration. There was no significant effect of haematocrit (41.5 to 62%), gestation, or operator on the accuracy of the BM lactate meter. The Accusport handheld lactate meter is an accurate, commercially available, method of measuring plasma lactate levels in only 60 seconds at the point-of-care. It requires only 15 microL of blood and is significantly cheaper than other assay methods. The BM lactate meter is well suited to assess lactic acidaemia of fetal scalp and neonatal blood samples to help quantify hypoxic stress in the perinatal period.