A Risk Assessment of the Jaffe vs Enzymatic Method for Creatinine Measurement in an Outpatient Population

Outcome-based analytical performance specifications: current status and future challenges

Analytical performance specifications (APS) based on outcomes refer to how 'good' the analytical performance of a test needs to be to do more good than harm to the patient. Analytical performance of a measurand affects its clinical performance. Without first setting clinical performance requirements, it is difficult to define how good analytically the test needs to be to meet medical needs. As testing is indirectly linked to health outcomes through clinical decisions on patient management, often simulation-based studies are used to assess the impact of analytical performance on the probability of clinical outcomes which is then translated to Model 1b APS according to the Milan consensus. This paper discusses the related key definitions, concepts and considerations that should assist in finding the most appropriate methods for deriving Model 1b APS. We review the advantages and limitations of published methods and discuss the criteria for transferability of Model 1b APS to different settings. We consider that the definition of the clinically acceptable misclassification rate is central to Model 1b APS. We provide some examples and guidance on a more systematic approach for first defining the clinical performance requirements for tests and we also highlight a few ideas to tackle the future challenges associated with providing outcome-based APS for laboratory testing.

Application and comparison of point-of-care devices for field evaluation of underlying health status of Guatemalan sugarcane workers

With chronic disease prevalence on the rise globally, surveillance and monitoring are critical to improving health outcomes. Point-of-care (POC) testing can facilitate epidemiological research and enhance surveillance systems in limited resource settings, but previous research has identified bias between POC devices and laboratory testing. We compared the performance of two POC blood analyzers, the iSTAT handheld (Abbott, Princeton, NJ, USA) and the StatSensor Creatinine (Nova Biomedical, Waltham, MA, USA) to concurrent blood samples analyzed at a local laboratory that were collected from 89 agricultural workers in Guatemala. We measured creatinine and other measures of underlying health status with the POC and the lab blood samples. Pearson correlation coefficients, Bland-Altman plots, no intercept linear regression models and two-sample t-tests were used to evaluate the agreement between the POC and lab values collected across three study days and to assess differences by study day in a field setting. On average there was no observed difference between the iSTAT and lab creatinine measurements (p = 0.91), regardless of study day. Using lab creatinine as the gold standard, iSTAT creatinine results were more accurate compared to the Statsensor, which showed some bias, especially at higher values. The iSTAT had good agreement with the lab for sodium and blood urea nitrogen (BUN), but showed differences for potassium, anion gap, bicarbonate (TCO2), glucose, and hematocrit. In this tropical field setting, the research team devised a protocol to prevent the devices from overheating. In limited resource settings, POC devices carry advantages compared to traditional lab analyses, providing timely results to patients, researchers, and healthcare systems to better evaluate chronic health conditions. Technical challenges due to use of POC devices in high heat and humidity environments can be addressed using a standard protocol for transporting and operating the devices.

Improved solution-based SERS detection of creatinine by inducing hydrogen-bonding interaction for effective analyte capture

Recently, solution-based surface-enhanced Raman scattering (SERS) detection technique has been widely recognized due to its cost-effectiveness, simplicity, and ease of use. However, solution-based SERS is limited for practical applications mainly because of the weak adsorption affinity of the target biomolecules to the surface of plasmonic nanoparticles. Herein, we developed a highly sensitive solution-based SERS sensing platform based on mercaptopropionic acid (MPA)-capped silver-coated gold nanostars (SGNS@MPA), which allows efficient enrichment on the nanostars surface for improved detection of an analyte: creatinine, a potential biomarker of chronic kidney disease (CKD). The SGNS@MPA exhibited high enrichment ability towards creatinine molecules in alkaline medium (pH-9) through multiple hydrogen bonding interaction, which causes aggregation of the nanoparticles and enhances the SERS signal of creatinine. The detection limit for creatinine was achieved at 0.1 nM, with a limit of detection (LOD) value of 14.6 pM. As a proof-of-concept demonstration, we conducted the first quantitative detection of creatinine in noninvasive human fluids, such as saliva and sweat, under separation-free conditions. We achieved a detection limit of up to 1 nM for both saliva and sweat, with LOD values as low as 0.136 nM for saliva and 0.266 nM for sweat. Overall, our molecular enrichment strategy offers a new way to improve the solution-based SERS detection technique for real-world practical applications in point-of-care settings and low-resource settings.

Socioeconomic differences associated with consumption of a plant-based diet: Results from the national health and nutrition examination survey

BACKGROUND

A plant-based diet (PBD) has been associated with potential health benefits, but factors that may affect access to and consumption of a PBD are not well defined.

AIM

To determine the association between socioeconomic status and plant-based dietary consumption among participants enrolled in the National Health and Nutrition Examination Survey (NHANES).

METHODS

This was a cross-sectional study using data obtained from the NHANES database. The following covariates were assessed: age, sex, race/ethnicity, educational level, marital status, smoking status, physical activity, alcohol use, history of diabetes, and hypertension. Socioeconomic status was categorized according to poverty-income ratio (PIR). Food frequency questionnaires were used to calculate previously validated plant-based diet index (PDI) and healthful plant-based diet index (hPDI). Multivariable-adjusted logistic regression was performed to determine the association between PIR, clinical, demographic, and plant-based diet indices.

RESULTS

A total of 5037 participants were in the final analytic sample. Median age of participants was 51 ± 18.5 years. Overall PDI and hPDI were 50 [46-54] and 52 [47-57], respectively. Median PDI index was significantly different among PIR groups (PDI, p = 0.018; hPDI, p < 0.001). On multivariable analysis, participants in the poorest socioeconomic group (PIR ≤ 130%) were more likely to have lower consumption of a healthful PBD (hPDI).

CONCLUSION

Lower socioeconomic status (PIR ≤ 130%) was associated with decreased consumption of a healthful plant-based diet. These data suggest that socioeconomic disparities may limit consumption of healthier food and contribute to the high prevalence of adverse health conditions that exist in certain population groups.

Selective Partitioned Regression for Accurate Kidney Health Monitoring

The number of people diagnosed with advanced stages of kidney disease have been rising every year. Early detection and constant monitoring are the only minimally invasive means to prevent severe kidney damage or kidney failure. We propose a cost-effective machine learning-based testing system that can facilitate inexpensive yet accurate kidney health checks. Our proposed framework, which was developed into an iPhone application, uses a camera-based bio-sensor and state-of-the-art classical machine learning and deep learning techniques for predicting the concentration of creatinine in the sample, based on colorimetric change in the test strip. The predicted creatinine concentration is then used to classify the severity of the kidney disease as healthy, intermediate, or critical. In this article, we focus on the effectiveness of machine learning models to translate the colorimetric reaction to kidney health prediction. In this setting, we thoroughly evaluated the effectiveness of our novel proposed models against state-of-the-art classical machine learning and deep learning approaches. Additionally, we executed a number of ablation studies to measure the performance of our model when trained using different meta-parameter choices. Our evaluation results indicate that our selective partitioned regression (SPR) model, using histogram of colors-based features and a histogram gradient boosted trees underlying estimator, exhibits much better overall prediction performance compared to state-of-the-art methods. Our initial study indicates that SPR can be an effective tool for detecting the severity of kidney disease using inexpensive lateral flow assay test strips and a smart phone-based application. Additional work is needed to verify the performance of the model in various settings.

Establishing age and gender-specific serum creatinine reference ranges for Thai pediatric population

Accurate assessment of kidney function in children requires age and gender-specific reference ranges for serum creatinine. Traditional reference values, often derived from adult populations and different ethnic backgrounds, may not be suitable for children. This study aims to establish specific reference ranges for serum creatinine in the Thai pediatric population, addressing the gap in localized and age-appropriate diagnostic criteria. This retrospective study analyzed serum creatinine levels from Thai children aged newborn to 18 years, collected from the Laboratory Information System of the Queen Sirikit National Institute of Child Health from January 2017 to December 2021. The Bhattacharya method was employed to establish reference ranges, considering different age groups and genders. The study compared these newly established reference values with international studies, including those of Schlebusch H., Pottel H., and Chuang GT., to validate their relevance and accuracy. A total of 27,642 data entries (15,396 males and 12,246 females) were analyzed. The study established distinct reference ranges for serum creatinine, which varied significantly across different age groups and between genders. These ranges were found to gradually increase with age from 2 months to 18 years. The study also highlighted notable differences in reference values when compared with other ethnic populations. The study successfully establishes tailored reference ranges for serum creatinine in Thai children, providing a valuable tool for more accurate diagnosis and monitoring of kidney health in this demographic. This initiative marks a significant advancement in pediatric nephrology in Thailand and suggests a need for continuous refinement of these ranges and further research in this area.

Performance of Modification of Diet in Renal Disease and Chronic Kidney Disease Epidemiology Collaboration Equations Versus 99Tc-DTPA-Renogram in Assessing Kidney Function

Objectives

To evaluate the performance of measurement of glomerular filtration rate (GFR) using Modification of Diet in Renal Disease equations (MDRD186, MDRD175) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations, in comparison with technetium-99m diethylenetriaminepentaacetic acid (99Tc-DTPA) renogram method, the gold standard. A related aim was to correlate the three equations to estimate GFR and their impact on reclassifying the stages of CKD in adult Omani patients.

Methods

This cross-sectional study recruited two groups of patients diagnosed with CKD during a 10-month period from January to October 2021. The first group comprised 48 patients who underwent a 99Tc-DTPA renogram procedure for GFR measurement, and the second group comprised 30 348 adult patients who did not undergo the same procedure; estimated GFR was calculated using the three equations.

Results

The median of the reference GFR was 106.0 mL/min/1.73 m2, whereas the median estimated GFR for the MDRD175, MDRD186, and CKD-EPI equations were 92.5, 98.3, and 102.1, respectively. All three equations correlated moderately with the reference GFR (0.428, 0.428, 0.523, respectively; p < 0.010). The CKD-EPI showed lesser bias (3.7 vs. 12.9 and 7.5 for MDRD175 and MDRD186, respectively) and more accuracy (95.8% vs. 91.7% and 93.8%); however, it was the least precise (25.1 vs. 22.3 and 23.8). The MDRD186 performed similarly to the CKD-EPI equation at CKD stages 3a-5 and differed significantly at stages 1-2. Whereas the MDRD175 differed significantly with both equations at stages 1-3b and was similar to them at stages 4-5.

Conclusions

The CKD-EPI equation had the highest accuracy and the least bias and precision in the general population. The MDRD186 CKD classification differed significantly from the CKD-EPI equation at CKD-stages 1-2 only. The CKD-EPI equation is preferred to MDRD for the detection and classification of early CKD stages.

Population pharmacokinetics of lisinopril in hypertensive children and adolescents with normal to mildly reduced kidney function

AIMS

Lisinopril, an angiotensin-converting enzyme inhibitor, is a frequently prescribed antihypertensive drug in the paediatric population, while being used off-label under the age of 6 years in the USA and for all paediatric patients globally. The SAFEPEDRUG project (IWT-130033) investigated lisinopril pharmacokinetics in hypertensive paediatric patients corresponding with the day-to-day clinical population.

METHODS

The dose-escalation pilot study included 13 children with primary and secondary hypertension who received oral lisinopril once daily in the morning; doses ranged from 0.05 to 0.2 mg kg-1 . Patients were aged between 1.9 and 17.9 years (median 13.5 years) and weight ranged between 9.62 and 97.2 kg (median 53.2 kg). All data were analysed using Monolix version 2020R1 (Lixoft, France) and R version 3.6.2.

RESULTS

A 1-compartment model with first-order absorption and first-order elimination optimally describes the data. Parameter estimates of absorption rate constant (0.075 h-1 [0.062, 0.088], typical value [95% confidence interval]), volume of distribution (31.38 L 70 kg-1 [10.5, 52.3]) and elimination clearance (24.2 L h-1 70 kg-1 [19.5, 28.9]) show good predictive ability. Significant covariate effects include total body weight on elimination clearance, and distribution volume and estimated glomerular filtration rate (eGFR) on elimination clearance. The effects of eGFR on the elimination clearance are optimally described by a linear effect centred around 105 mL min-1  1.73 m-2 . The effects of body weight were implemented using fixed allometric exponents centred around an adult weight of 70 kg.

CONCLUSION

Lisinopril dose and regimen adjustments for paediatric patients should include eGFR on top of weight adjustments. An expanded model characterizing the pharmacodynamic effect is required to identify the optimal dose and dosing regimen.

Comparison of Pakistani CKD-EPI, new Asian-modified CKD-EPI and revised Lund-Malmö study equations in a South Asian CKD population: a study from a Pakistani CKD cohort

BACKGROUND

Newly proposed estimating glomerular filtration rate equations need to be studied, evaluated and compared for chronic kidney disease staging, diagnosis and medication dosing in South Asians. The objectives of the study were (1) to assess the performance of the CKD-EPIPK, CKD-EPIAsian-Modified, and LMRevised equations in the Pakistani chronic kidney disease population, and (2) to investigate prospective implications on chronic kidney disease classification and end-stage kidney disease prevalence.

METHODS

We conducted a cross-sectional analysis on a chronic kidney disease cohort of 385 participants 18 years of age or above.

RESULTS

CKD-EPIPK showed the lowest bias (- 1.33 ml/min/1.73 m2), highest precision [IQR, 2.33 (- 2.36, - 0.03)] and enhanced P30 accuracy (89.35%) compared to the CKD-EPIAsian-Modified and LMRevised equations. The mean difference (ml/min/1.73 m2), 95% limit of agreement (ml/min/1.73 m2) of the equations were; CKD-EPIAsian-Modified: - 5.98, - 13.03, LMRevised: - 4.06, - 8.13 and CKD-EPIPK: - 1.18, - 6.14 (P < 0.001). CKD-EPIAsian-Modified and LMRevised showed upward re-classification of the GFR categories compared to the CKD-EPIPK equation except in the G5 category where the highest count (217, 56.36%) was noted for the CKD-EPIPK equation. End-stage kidney disease prevailed in all age groups according to all equations, and the prevalence was high in females in all equations.

CONCLUSION

CKD-EPIPK showed the best performance, whereas both CKD-EPIAsian-Modified and LMRevised showed poor performance and did not offer a sufficient advantage in chronic kidney disease classification and end-stage kidney disease prevalence estimation over CKD-EPIPK. Hence, CKD-EPIPK seems ideal for South Asians, thus appropriate measures should be taken for its implementation, at least in Pakistani laboratories.

The estimation of glomerular filtration in acute and critical illness: Challenges and opportunities

Recent events have made it apparent that the creatinine based estimating equations for glomerular filtration have their flaws. Some flaws have been known for some time; others have prompted radical modification of the equations themselves. These issues persist in part owing to the behaviour of the creatinine molecule itself, particularly in acute and critical illness. There are significant implications for patient treatment decisions, including drug and fluid therapies and choice of imaging modality (contrast vs. non-contrast CT scan for example). An alternative biomarker, Cystatin C, has been used with some success both alone and in combination with creatinine to help improve the accuracy of particular estimating equations. Problems remain in certain circumstances and costs may limit the more widespread use of the alternative assay. This review will explore both the historical and more recent evidence for glomerular filtration estimation, including options to directly measure glomerular filtration (rather than estimate), perhaps the holy grail for both Biochemistry and Nephrology.

Pseudohypercreatininemia after surgery for aortic dissection: a case report

BACKGROUND

Elevated creatinine concentrations often indicate acute renal injury and renal biopsies are considered in this situation. However,pseudohypercreatininemia is potential cause of elevated creatinine concentrations, and invasive interventions should be avoided.

CASE PRESENTATION

A 54-year-old woman underwent surgery for descending aortic dissection.Nine days postoperatively, her creatinine concentration increased from 1 mg/dl to 5.78 mg/dl (normal range, 0.47-0.7 mg/dl). Azotemia and hyperkalemia were absent and physical examination findings were unremarkable. Cystatin C concentration was 1.56 mg/l (normal range, 0.56-0.8 mg/l) and pseudohypercreatininemia was suspected. Testing with different reagents showed a creatinine concentration of 0.84 mg/dl. Immunoglobulin (Ig)G was markedly elevated, and creatinine and IgG fluctuated in parallel, suggesting the cause of the pseudohypercreatininemia. IgG4 was also elevated at 844 mg/dl. Immunosuppressive steroid therapy effectively decreased the IgG concentration and resolved the pseudohypercreatininemia.

CONCLUSIONS

In cases of elevated creatinine concentration with the presence of abnormal proteins, pseudohypercreatininemia should be considered. We report a rare case of pseudohypercreatininemia caused by polyclonal IgG.

Comparison of Jaffe Method and Enzymatic Method at Measuring Serum Creatinine Level, Creatinine Clearance and Estimated Glomerular Filtration Rate

Background

Correct measuring of blood and urine creatinine level is necessary for identification and tracking of chronic kidney disease (CKD).

Objective

The aim of this study is a comparison of Jaffe and enzymatic methods for measuring creatinine in serum and in urine, in order to determine whether there are any statistical significant differences between them, and whether they are reflected on creatinine clearance calculation and estimated glomerular filtration rate (eGFR).

Methods

Creatinine in serum and urine was measured for the group of patients (N=60; female=34, male=26) from 24 to 69 years of age by using Jaffe's method on Dimension RxL biochemical analyzer, and enzymatic method on integrated biochemical and immunochemical analyzer Architect ci8200, and obtained levels are used for creatinine clearance calculation and eGFR.

Results

The methods correlate well, both in measuring serum creatinine (r 1 = 0.990) and in measuring urine creatinine (r 2 =0.974). There are no statistically significant differences between them (p=0.57). Measuring creatinine using different methods showed no statistically significant differences in the calculated clearances (p=0.93), they significantly correlate (r=0.9722). eGFR, using the MDRD and CKD-EPI formulas, were not statistically significantly different, regardless of the used method.

Conclusion

Apart from significant correlations between the used methods, the results of using the Jaffe and enzymatic methods showed no significant differences at measuring serum creatinine level, or creatinine clearance and glomerular filtration rate.

Incidence and factors associated with acute kidney injury among children with type 1 diabetes hospitalized with diabetic ketoacidosis: A prospective study

BACKGROUND AND OBJECTIVES

Acute kidney injury (AKI) is frequent among critically ill children. This study aimed to assess the incidence and factors associated with AKI among children with type 1 diabetes mellitus (T1DM) hospitalized with diabetic ketoacidosis (DKA).

METHODS

This prospective observational study was conducted at Sohag University Hospital, Egypt over 1 year. Children aged 6 months to 12 years, diagnosed with T1DM and hospitalized with the criteria of DKA were included. The study participants received intravenous fluid therapy and intravenous insulin infusion for DKA management. Serum creatinine levels were measured at admission, 24 and 48 h after admission. AKI was defined and staged using the Kidney Disease Improving Global Outcomes serum creatinine criteria.

RESULTS

The study included 265 DKA episodes in 240 participants. AKI was found in 110 (41.5%) DKA episodes. Moderated to severe AKI developed in 41 (15.5%) episodes. Multivariate regression analysis revealed that age (adjusted odds ratio = 0.78, 95% confidence interval (CI): 0.69-0.89, p < 0.001), Glasgow-Coma scale (GCS) < 14 at admission (adjusted odds ratio = 4.66, 95% CI: 1.66-13.14, p = 0.004) and serum chloride level at 12 h (adjusted odds ratio = 1.10, 95% CI: 1.02-1.18, p = 0.01) were the most significant factors associated with moderate to severe AKI development.

CONCLUSIONS

AKI is common among T1DM children hospitalized with DKA. Younger age, low GCS at hospital admission and increased serum chloride level during DKA management were associated with increased risk for moderate to severe AKI development.

Clinical application of the StatSensor and StatSensor Xpress point-of-care creatinine measurement devices in dogs

BACKGROUND

Creatinine is a universally important blood parameter used to detect and monitor acute and chronic kidney disease. Reliable measurements at the bedside remain a challenge in human and veterinary medicine. Despite its potential, a trustworthy point-of-care creatinine biosensor has yet to be established.

OBJECTIVES

We aimed to determine the precision and accuracy of the StatSensor (SS) and StatSensor Xpress (SSX) handheld creatinine measurement devices in dogs.

METHODS

Paired creatinine samples from dogs with normal (creatinine ≤159 μmol/L), moderate (159-354 μmol/L), and marked (>354 μmol/L) azotemia were compared with a commercial enzymatic analyzer. Within-day precision and linearity studies were performed prior to method comparison studies. Method comparison was evaluated using Bland-Altman, concordance correlation coefficient, Deming, and Passing-Bablok regression analysis.

RESULTS

Seventy-eight dogs were enrolled in the study, including 28 (35%), 25 (32%), and 26 (33%) with normal, moderate, and marked azotemia. Total error surpassed recommendations for all devices, and linearity deviated from identity for the SS1 and SS2. The concordance correlation coefficients of the SS1, SS2, SSXI, and SSX2, were 0.69, 0.59, 0.82, and 0.44, respectively. Bland-Altman analyses showed a high variation in the differences, and relationships showed high heteroskedasticity with negative systemic bias among high creatinine concentrations.

CONCLUSIONS

Neither the SS and SSX are considered acceptable for clinical applications in dogs. Further research is indicated for the development of a reliable, cost-effective, point-of-care creatinine analyzer to improve the rapid detection and monitoring human and veterinary patients.

A disposable printed amperometric biosensor for clinical evaluation of creatinine in renal function detection

In clinical practice, sera creatinine level is regarded as a crucial biomarker for the diagnosis, staging and monitoring of kidney disease. An amperometric biosensor is rapid, accurate, and cost-effective, with a portability and a simple operation. Herein, we report for the firsttime a disposable, printed amperometric biosensor for the clinical evaluation of creatinine in renal function detection. The sensor is constructed based on Prussian blue/carbon-graphite paste as the working electrode and the immobilization of creatinine amidohydrolase, creatine amidinohydrolase and sarcosine oxidase. The creatinine biosensor shows a linear detection range from 0.05 to 1.4 mM with a detection time of about 3 min. In addition, the sensor shows a high stability that can maintain above 86% of the initial activity after being stored for over 4 months. Moreover, the sensor shows almost the same results as those with the Jaffe method for measuring the real blood samples. We anticipate that the creatinine biosensor could be widely used in the medical and healthcare areas, especially for at-home testing and onsite medical examinations.

Health Risk Assessment of Exposure to 15 Essential and Toxic Elements in Spanish Women of Reproductive Age: A Case Study

This case study investigates the exposure of 119 Spanish women of reproductive age to 5 essential (Co, Cu, Mn, V, Zn) and 10 toxic (Ba, Be, Cs, Ni, Pb, Pt, Sb, Th, Al, U) elements and assesses their risk. The essential elements (Co, Cu, Mn, V, and Zn) showed average concentrations (GM: geometric mean) of 0.8, 35, 0.5, 0.2, and 347 μg/L, respectively. Five of the toxic elements (Ba, Cs, Ni, Al, U) exhibited detection frequencies of 100%. The GM concentrations of the novel toxic elements were 12 μg/L (Al), 0.01 μg/L (Pt), 0.02 μg/L (U), 0.12 μg/L (Th), 0.009 μg/L (Be) and 4 μg/L (Cs). The urine analysis was combined with a survey to assess any variations between subgroups and potential predictors of exposure to elements in the female population. Significant differences were obtained between the rural and urban areas studied for the toxic element Cs, with higher levels found in mothers living in urban areas. In relation to diet, statistically significantly higher levels of essential (Cu) and toxic (Ba) elements were detected in women with a high consumption of fish, while mothers who consumed a large quantity of legumes presented higher levels of the toxic element Ni (p = 0.0134). In a risk-assessment context, hazard quotients (HQs) greater than 1 were only observed for the essential elements Zn and Cu in P95. No deficiency was found regarding the only essential element for which a biomonitoring equivalent for nutritional deficit is available (Zn). For the less-studied toxic elements (Al, Pt, U, Th, Be, and Cs), HQs were lower than 1, and thus, the health risk due to exposure to these elements is expected to be low for the female population under study.

Evaluating kidney function using a point-of-care creatinine test in Ugandan children with severe malaria: a prospective cohort study

Background

Acute kidney injury (AKI) disproportionately affects individuals in low-and middle-income countries (LMIC). However, LMIC—particularly countries in sub-Saharan Africa— are under-represented in global AKI research. A critical barrier in diagnosing AKI is access to reliable serum creatinine results. We evaluated the utility of a point-of-care test to measure creatinine and diagnose AKI in Ugandan children with malaria.

Methods

Paired admission creatinine was assessed in 539 Ugandan children 6 months to 4 years of age hospitalized with severe malaria based on blood smear or rapid diagnostic test. Creatinine levels were measured using isotope dilution mass spectrometry (IDMS)-traceable methods. The reference creatinine was measured using the modified Jaffe method by a certified laboratory and the point-of-care testing was conducted using an i-STAT blood analyzer (i-STAT1, with and without adjustment for the partial pressure of carbon dioxide). AKI was defined and staged using the Kidney Disease: Improving Global Outcomes criteria.

Results

The mean age of children was 2.1 years, and 21.6% of children were stunted. Mortality was 7.6% in-hospital. Over the entire range of measured creatinine values (<0.20mg/dL-8.4mg/dL), the correlation between the reference creatinine and adjusted and unadjusted point-of-care creatinine was high with R² values of 0.95 and 0.93 respectively; however, the correlation was significantly lower in children with creatinine values <1mg/dL (R² of 0.44 between the reference and adjusted and unadjusted i-STAT creatinine). The prevalence of AKI was 45.5% using the reference creatinine, and 27.1 and 32.3% using the unadjusted and adjusted point-of-care creatinine values, respectively. There was a step-wise increase in mortality across AKI stages, and all methods were strongly associated with mortality (p<0.0001 for all). AKI defined using the reference creatinine measure was the most sensitive to predict mortality with a sensitivity of 85.4% compared to 70.7 and 63.4% with the adjusted and unadjusted point-of-care creatinine values, respectively.

Conclusions

Point-of-care assessment of creatinine in lean Ugandan children <4 years of age underestimated creatinine and AKI compared to the clinical reference. Additional studies are needed to evaluate other biomarkers of AKI in LMIC to ensure equitable access to AKI diagnostics globally.

AACC Guidance Document on Laboratory Investigation of Acute Kidney Injury

BACKGROUND

Acute kidney injury (AKI) is a sudden episode of kidney damage or failure affecting up to 15% of hospitalized patients and is associated with serious short- and long-term complications, mortality, and health care costs. Current practices to diagnose and stage AKI are variable and do not factor in our improved understanding of the biological and analytical variability of creatinine. In addition, the emergence of biomarkers, for example, cystatin C, insulin-like growth factor binding protein 7, and tissue inhibitor of metalloproteinases 2, and electronic notification tools for earlier detection of AKI, highlights the need for updated recommendations to address these developments.

CONTENT

This AACC Academy guidance document is intended to provide laboratorians and clinicians up-to-date information regarding current best practices for the laboratory investigation of AKI. Topics covered include: clinical indications for further investigating potential AKI, analytical considerations for creatinine assays, the impact of biological variability on diagnostic thresholds, defining "baseline" creatinine, role of traditional markers (urine sodium, fractional excretion of sodium, fractional excretion of urea, and blood urea-to-creatinine ratio), urinary microscopic examination, new biomarkers, improving AKI-associated test utilization, and the utility of automated AKI alerts.

SUMMARY

The previous decade brought us a significant number of new studies characterizing the performance of existing and new biomarkers, as well as potential new tools for early detection and notification of AKI. This guidance document is intended to inform clinicians and laboratorians on the best practices for the laboratory investigation of AKI, based on expert recommendations where the preponderance of evidence is available.

Malaria-Associated Acute Kidney Injury in African Children: Prevalence, Pathophysiology, Impact, and Management Challenges

Acute kidney injury (AKI) is emerging as a complication of increasing clinical importance associated with substantial morbidity and mortality in African children with severe malaria. Using the Kidney Disease: Improving Global Outcomes (KDIGO) criteria to define AKI, an estimated 24–59% of African children with severe malaria have AKI with most AKI community-acquired. AKI is a risk factor for mortality in pediatric severe malaria with a stepwise increase in mortality across AKI stages. AKI is also a risk factor for post-discharge mortality and is associated with increased long-term risk of neurocognitive impairment and behavioral problems in survivors. Following injury, the kidney undergoes a process of recovery and repair. AKI is an established risk factor for chronic kidney disease and hypertension in survivors and is associated with an increased risk of chronic kidney disease in severe malaria survivors. The magnitude of the risk and contribution of malaria-associated AKI to chronic kidney disease in malaria-endemic areas remains undetermined. Pathways associated with AKI pathogenesis in the context of pediatric severe malaria are not well understood, but there is emerging evidence that immune activation, endothelial dysfunction, and hemolysis-mediated oxidative stress all directly contribute to kidney injury. In this review, we outline the KDIGO bundle of care and highlight how this could be applied in the context of severe malaria to improve kidney perfusion, reduce AKI progression, and improve survival. With increased recognition that AKI in severe malaria is associated with substantial post-discharge morbidity and long-term risk of chronic kidney disease, there is a need to increase AKI recognition through enhanced access to creatinine-based and next-generation biomarker diagnostics. Long-term studies to assess severe malaria-associated AKI’s impact on long-term health in malaria-endemic areas are urgently needed.

Avoiding insufficient therapies and overdosing with co-reporting eGFRs (estimated glomerular filtration rate) for personalized drug therapy and improved outcomes - a simulation of the financial benefits

Patients with impaired renal function are at high risk for morbidity and mortality. Chronic kidney disease (CKD) even in the early stages can be associated with significant side effects of drug therapy, longer length of stay, and high costs. Correct assessment of renal function in the hospital is important to detect CKD, to avoid further damage to the kidneys, and to optimize pharmacological therapy. Current protocols for renal function testing in drug dosing are only creatinine based, are not robust enough, and can wrongly classify certain patients. Goal of our simulation study is to optimize noninvasive renal function estimates and to allow for optimal dosing of pharmacological treatment without further renal damage. Co-reporting of creatinine- and of cystatin C-derived estimated glomerular filtration rates (eGFR) allows a personalized approach for patients with large discrepancies in eGFR and it enabled us in detecting patients at high risk for side effects due to incorrect drug dosing. This approach might be highly effective for patients as well as for clinicians. In addition, we simulated the efficiency by estimating savings for the hospital administration and the payor with a benefit cost ratio of 58 to 1.

A phase II, open-labeled, single-arm study of dose-dense paclitaxel plus carboplatin in advanced or recurrent uterine endometrial cancer treatment: a KCOG-G1303, DOENCA trial

Objective

To determine the safety and efficacy of dose-dense (dd) paclitaxel (PTX) and carboplatin (CBDCA) in treating advanced or recurrent endometrial cancer.

Methods

Women aged 20–75 years with histologically confirmed endometrial cancer, the International Federation of Gynecology and Obstetrics (FIGO) stage III disease with some residual tumor, FIGO stage IV disease, recurrence after front-line curative treatment, or recurrence after second-line chemotherapy or radiotherapy were enrolled in this study. PTX (80 mg/m²) was administered intravenously (IV) to every participant on days 1, 8, and 15, and CBDCA (area under the curve of 5) was administered IV on day 1 once every 3 weeks until the disease progressed, unacceptable adverse events occurred, or consent was withdrawn. The primary endpoint was the response rate (RR), while the secondary endpoints were progression-free survival, overall survival, and adverse effects.

Results

Forty-eight participants were enrolled, and 46 were eligible to receive treatment. The patients' median age was 61 years (range, 43–76 years). Twenty-two participants had experienced recurrence, and the remaining patients had primary advanced endometrial cancer. There were 10 cases of serous carcinoma, 3 cases of endometrioid carcinoma G3, 2 cases of carcinosarcoma, and 2 cases of clear-cell carcinoma according to histology. Twenty-nine participants (63.0%) received ≥6 cycles of chemotherapy. The RR (complete, 13 cases; partial, 20 cases) was 71.3% (95% confidence interval: 59.0%–84.5%).

Conclusion

The dd PTX with CBDCA is feasible and available as a treatment option for advanced or recurrent endometrial cancer.

Trial Registration

UMIN Clinical Trials Registry Identifier: UMIN000017138

Measurement of serum creatinine levels with liquid chromatography-tandem mass spectrometry: comparison with Jaffe and enzymatic methods

Objectives

Our aim was to validate a mass spectrometric creatinine method and compare this method with Jaffe and enzymatic serum creatinine methods.

Methods

90 samples were included. The levels were classified into three groups according to serum creatinine results as Group 1: Lower (n=30) (0.16–0.59 mg/dL), Group 2: Normal (n=30) (0.62–1.18 mg/dL) and Group 3: Higher (n=30) (1.33–3.88 mg/dL). Jaffe and enzymatic creatinine measurements were performed on the Beckman Coulter AU5800 autoanalyzer.

Results

Serum creatinine was linear from 0.039 up to 10 mg/dL, CV and bias values were ranged between 1.9–3.8% and 2–15%. Correlation coefficients were 0.990 (95% confidence interval 0.984–0.993), 0.992 (95% confidence interval 0.988–0.995) and 0.994 (95% confidence interval 0.991–0.996) for LC-MS/MS-Enzymatic, LC-MS/MS-Jaffe and Enzymatic-Jaffe, respectively.

Conclusions

Although, Jaffe method for serum creatinine measurement is still much more practical and cheap, so in use for routine practice, tandem mass spectrometric detection of serum creatinine can be used as an accurate and specific method for verification of discordant clinical results, existence of possible interferences and serum levels under 0.5 mg/dL creatinine results such as pediatric or pregnant populations.

Cefoxitin-Serum Creatinine Interference in a Patient With Nontuberculous Mycobacteria Ventriculomeningitis

Cefoxitin is a second-generation cephamycin antibiotic, which at concentrations ≥100 µg/mL is known to modestly interfere, for up to 2 hours post-infusion, with serum creatinine measurement via the traditional Jaffe-based assay. We report a case of a severe serum creatinine elevation while utilizing cefoxitin as a component of an antimicrobial regimen in a critically ill patient with Mycobacterium abscessus ventriculomeningitis. Our results, both via patient serum analysis and a cefoxitin spiking experiment, demonstrate interference despite the utilization of improved modern Jaffe-based assays. In fact, the cefoxitin-creatinine interference may be clinically relevant at concentrations 3 times lower than that listed in the package insert and may display more than a modest interference at typical therapeutic concentrations.

Clinical and Analytical Impact of Moving from Jaffe to Enzymatic Serum Creatinine Methodology

Background

Identification and monitoring of chronic kidney disease (CKD) requires accurate quantification of serum creatinine. The poor specificity of Jaffe creatinine methods is well documented, and guidelines recommend enzymatic methodology. We describe our experience of moving from Jaffe to enzymatic creatinine methodology. We present comparison of &gt;5000 paired Jaffe and enzymatic creatinine results, examine interferences, and attempt to assess clinical consequences of changing methodology.

Methods

Overall, 5303 serum samples received for routine creatinine measurement were analyzed using Jaffe and enzymatic methods with an Abbott Architect autoanalyzer. Associated results for glucose, total bilirubin, triglycerides, total protein, and hemolytic, icteric, and lipemic indexes were extracted from the laboratory database. CKD staging was estimated for each sample to assess potential clinical effects.

Results

The methods correlated well (r = 0.996) and showed good agreement (Passing-Bablok fit, y = 0.935x + 0.074). Paired analysis, however, showed significant differences (P &lt; 0.001), and approximately 20% of results differed by more than ±10%. Multivariate analysis demonstrated independent associations between difference in creatinine results, glucose (P &lt; 0.0001), and hemolytic index (P = 0.009). Glucose demonstrated positive interference in the Jaffe method, and hemolysis produced negative interference in the enzymatic method. Little or no association was observed with other analytes. CKD staging differed in 4% of samples.

Conclusions

Differences between Jaffe and enzymatic serum creatinine results exceed the recommended 5% target for a significant proportion of samples, particularly at concentrations &lt;1.13 mg/dL (100 µmol/L). Both glucose and hemolysis contribute to the variance in results. Although the clinical impact of these differences seems small, laboratories should continue moving toward enzymatic creatinine estimation to ensure the best estimate of renal function.

Comparison of glomerular filtration rate estimation using Jaffé and enzymatic creatinine assays in diabetic patients

BACKGROUND

Diabetic kidney disease (DKD) develops an end-stage renal failure and is a major cause of death in diabetic patients. A GFR below 60 ml/min per 1.73 m2 is one of the main markers of DKD. Therefore, the development of an accurate test for diagnosis and monitoring of the mentioned disease would be essential. Here, we examined the impacts of two different kits with different methods for creatinine measurement on the GFR values.

METHODS

Blood samples were collected from 80 diabetic patients referring to the clinical laboratory. The levels of serum creatinine were assessed using Jaffé and enzymatic assays by kits from two different manufacturers. Then to assess the eGFR levels, the MDRD equation was used. Further descriptive parameters of both methods and correlation of methods were also calculated.

RESULTS

Descriptive analysis of the data demonstrates a slight increase in the serum creatinine measured by Jaffé assay which leads to a substantial decrease in the levels of eGFR compared to the eGFR calculated by the enzymatic assay. Moreover, eGFR over 60 mL/min/1.73 m 2 in enzymatic assay was observed in 27.5% of participants while eGFR of the same participants was below 60 mL/min/1.73 m 2 when it was measured by Jaffé method. Consequently, 27.5% positive discordant cases were reported by Jaffé assay followed by misclassifying them as DKD patients compared with the enzymatic assay.

CONCLUSION

While using Jaffé assay, a low level of eGFR is observed which generates more misclassification into the DKD group and demands to an inclusive consideration by physicians in order to diagnose and monitor the DKD patients.

Biochemical evaluation of kidney disease

Different biochemical markers exist in both blood and urine for assessing renal function. Most of these biomarkers have advantages and limitations associated with their use, which is important to consider when ordering and utilising them in the clinical setting. The ideal marker should be able to detect acute kidney injury (AKI) at the onset and be used for the diagnosis and ongoing monitoring and management of kidney disease. The search for such a marker is ongoing, as all potential candidates thus far are associated with certain limitations. This article will attempt to compare and contrast established and emerging kidney disease markers.

Lower creatinine concentration values and lower inter-laboratory variation among Swedish hospital laboratories in 2014 compared to 1996: results from the Equalis external quality assessment program

Background

Creatinine measurement for estimation of glomerular filtration rate (GFR) is a frequently used laboratory test. Differences in analytic creatinine methods have caused large inter-laboratory variation. International and national standardization efforts have been made in the last decade.

Methods

This study describes the results of the standardization efforts in Sweden by summarizing data for creatinine concentration in blood plasma in the Equalis quality assessment program during 1996–2014.

Results

Non-compensated Jaffe methods dominated in 1996–2001 (91 of 103 laboratories; 90%) and were then gradually replaced by either compensated Jaffe methods or enzymatic creatinine methods. In 2014 a majority of Swedish hospital laboratories (139 of 159; 87%) used enzymatic methods. The reported mean creatinine value by the Swedish laboratories was about 10 μmol/L higher than the isotope dilution mass spectrometry (IDMS) assured reference value in 2003, but consistent with the reference value from 2009 to 2014. The inter-laboratory CV was 7%–9% for creatinine values until 2007, and thereafter gradually decreased to about 4%–5% in 2014.

Conclusions

The introduction of enzymatic methods in Swedish laboratories has contributed to achieving a low inter-laboratory variation. Also, the reported values are lower for enzymatic methods compared to Jaffe methods, and the values obtained with enzymatic methods were consistent with IDMS certified values established at reference laboratories. Thus, many Swedish hospital laboratories reported 10 μmol/L lower, and more true, creatinine concentrations in 2012 than in 2003, which may cause bias in longitudinal studies.

Chronic kidney disease and kidney health care status: the healthy life in Suriname (HeliSur) study

The high cardiovascular risk burden in low- and middle-income countries is expected to lead to an explosive increase in chronic kidney disease (CKD). However, population data on CKD from these countries are scarce. Therefore, we assessed kidney health in Suriname. In the Healthy Life in Suriname (HeliSur) study, a random sample of the adult population, we collected data with standardized questionnaires, physical examination, and blood and urine samples analysed in a central laboratory. Prevalent CKD was graded with KDIGO guidelines. In addition, we assessed national data on prevalent renal replacement therapy (RRT), estimated the future need for RRT, and evaluated national kidney health work force and policies. We include 1117 participants (2.0‰ of the population), 63% women, 40% of African ancestry and 43% of Asian ancestry, with a mean age of 42.2 (SE 0.4) years. Blood pressure is elevated in 72% of the participants, 26% have diabetes or prediabetes, and 78% are obese or overweight. The prevalence of CKD is 5.4%, and around 0.3% have kidney failure, translating to approximately 1500 patients nationally (2690 per million population, pmp), with currently 516 patients (920 pmp) on dialysis. Based on the participants from the random population sample in CKD stage G3 or G4, we estimate that 6750-10,750 pmp may develop kidney failure within the next 10 years. However, specialized kidney health workforce is currently very limited, and specific national or local policies for CKD management are lacking. Since the large majority of the general population has one or more risk factors for CKD including elevated blood pressure, urgent action is needed to strengthen kidney health care and prevent a catastrophic rise in need for RRT in the coming years.

Identification of young adults at risk of an accelerated loss of kidney function in an area affected by Mesoamerican nephropathy

BACKGROUND

After two-years of follow-up of 263 apparently healthy 18- to 30-year-old men in communities affected by Mesoamerican nephropathy (MeN), we identified three distinct case groups: a subgroup with (i) established renal dysfunction (case-group 1); individuals with (ii) a rapid decline in kidney function (case-group 2); and individuals with (iii) stable kidney function (non-cases). This paper investigates whether local tests are potentially useful for the timely identification of these case groups.

METHODS

Creatinine levels were measured in local laboratories every six months for two years. Aliquots were sent to a centralized laboratory for measurements of cystatin C and creatinine levels. We investigated agreement between the locally and centrally measured creatinine-based Chronic Kidney disease Epidemiology Collaboration (CKD-EPI) equation for estimating the Glomerular Filtration Rate (eGFR). A logistic regression analysis was used to assess predictive factors for case groups 1 and 2 compared to non-cases. Predictive variables were locally measured eGFR, and urinary neutrophil gelatinase-associated lipocalin (uNGAL) levels. The discrimination performance of the model was assessed using the area under the receiver operating characteristic curve (AUC).

RESULTS

Considerable variation in local eGFR measurements was observed. The prediction model for case-group 1 included baseline kidney function and with or without uNGAL (AUC = 0.98, 95% confidence interval (CI), 0.91-1.00). The prediction model for case-group 2 also required eGFRScr at six and twelve months after baseline, with or without uNGAL levels (AUC = 0.88; 95% CI 0.80-0.99).

CONCLUSIONS

Established renal dysfunction was detected at a single time point using local measurements and uNGAL. For the detection of a rapid decline in kidney function over time, at least 2 more measurements at six and twelve months are needed.

Irregular analytical errors in diagnostic testing - a novel concept

BACKGROUND

In laboratory medicine, routine periodic analyses for internal and external quality control measurements interpreted by statistical methods are mandatory for batch clearance. Data analysis of these process-oriented measurements allows for insight into random analytical variation and systematic calibration bias over time. However, in such a setting, any individual sample is not under individual quality control. The quality control measurements act only at the batch level. Quantitative or qualitative data derived for many effects and interferences associated with an individual diagnostic sample can compromise any analyte. It is obvious that a process for a quality-control-sample-based approach of quality assurance is not sensitive to such errors.

CONTENT

To address the potential causes and nature of such analytical interference in individual samples more systematically, we suggest the introduction of a new term called the irregular (individual) analytical error. Practically, this term can be applied in any analytical assay that is traceable to a reference measurement system. For an individual sample an irregular analytical error is defined as an inaccuracy (which is the deviation from a reference measurement procedure result) of a test result that is so high it cannot be explained by measurement uncertainty of the utilized routine assay operating within the accepted limitations of the associated process quality control measurements.

SUMMARY

The deviation can be defined as the linear combination of the process measurement uncertainty and the method bias for the reference measurement system. Such errors should be coined irregular analytical errors of the individual sample. The measurement result is compromised either by an irregular effect associated with the individual composition (matrix) of the sample or an individual single sample associated processing error in the analytical process.

OUTLOOK

Currently, the availability of reference measurement procedures is still highly limited, but LC-isotope-dilution mass spectrometry methods are increasingly used for pre-market validation of routine diagnostic assays (these tests also involve substantial sets of clinical validation samples). Based on this definition/terminology, we list recognized causes of irregular analytical error as a risk catalog for clinical chemistry in this article. These issues include reproducible individual analytical errors (e.g. caused by anti-reagent antibodies) and non-reproducible, sporadic errors (e.g. errors due to incorrect pipetting volume due to air bubbles in a sample), which can both lead to inaccurate results and risks for patients.

Estimated glomerular filtration ratio is a better index than creatinine clearance (Cockcroft-Gault) for predicting the prevalence of atrial fibrillation in the general Japanese population

Direct oral anti-coagulants (DOACs) have been used in patients with non-valvular atrial fibrillation (AF), and renal function evaluation using the CCr (Cockcroft-Gault) is recommended as a criterion for the reduction of DOAC. In contrast, estimated glomerular filtration rate (eGFR) is usually used as an index of renal function in daily practice. We determined the age- and gender-specific prevalence rates of AF and whether CCr or eGFR was associated with the prevalence of AF. Data from the periodic health examinations of 108,951 subjects were collected. Risk factors for AF were determined based on medical history, physical examinations and blood samples, and AF was diagnosed based on electrocardiography. The prevalence rate of AF was 0.92% (998/108,951). It was four times higher in men than in women and increased with age. Cardiac disease (odds ratio (OR) = 27.07, confidence interval (CI) 23.39-31.37, p = 0.0001), male gender (OR = 3.65, CI 3.11-4.30), age > 65 years (OR = 2.52, CI 2.14-2.96), hyperlipidemia (OR = 2.51, CI 1.97-3.20), BMI > 25 kg/m² (OR = 1.37, CI 1.19-1.58) and hypertension (OR = 1.14, CI 1.11-1.16) were independently associated with a high risk of AF in the multivariate logistic regression analysis. The odds ratio of having AF was significantly higher in patients with eGFR ≤ 59 (OR = 2.10, CI 1.21-3.86) than in those with eGFR ≥ 90 but was not associated with CCr after adjustments for age, gender, diabetes mellitus and smoking. The significance of this difference disappeared after additional adjustment for hypertension. Cardiac disease, gender, age, hyperlipidemia, obesity, hypertension and renal dysfunction were strong risk factors for AF. The evaluation of renal dysfunction as a morbidity risk factor for AF suggests that eGFR should be used.

Impact of creatinine methodology on glomerular filtration rate estimation in diabetes

AIM

To evaluate the influence of creatinine methodology on the performance of chronic kidney disease (CKD)-Epidemiology Collaboration Group-calculated estimated glomerular filtration rate (CKD-EPI-eGFR) for CKD diagnosis/staging in a large cohort of diabetic patients.

METHODS

Fasting blood samples were taken from diabetic patients attending our clinic for their regular annual examination, including laboratory measurement of serum creatinine and eGFR.

RESULTS

Our results indicated an overall excellent agreement in CKD staging (kappa = 0.918) between the Jaffé serum creatinine- and enzymatic serum creatinine-based CKD-EPI-eGFR, with 9% of discordant cases. As compared to the enzymatic creatinine, the majority of discordances (8%) were positive, i.e., associated with the more advanced CKD stage re-classification, whereas only 1% of cases were negatively discordant if Jaffé creatinine was used for eGFR calculation. A minor proportion of the discordant cases (3.5%) were re-classified into clinically relevant CKD stage indicating mildly to moderately decreased kidney function (< 60 mL/min per 1.73 m²). Significant acute and chronic hyperglycaemia, assessed as plasma glucose and HbA_1c levels far above the recommended glycaemic goals, was associated with positively discordant cases. Due to a very low frequency, positive discordance is not likely to present a great burden for the health-care providers, while intensified medical care may actually be beneficial for the small number of discordant patients. On the other hand, a very low proportion of negatively discordant cases (1%) at the 60 mL/min per 1.73 m² eGFR level indicate a negligible possibility to miss the CKD diagnosis, which could be the most prominent clinical problem affecting patient care, considering high risk of CKD for adverse patient outcomes.

CONCLUSION

This study indicate that compensated Jaffé creatinine procedure, in spite of the glucose-dependent bias, is not inferior to enzymatic creatinine in CKD diagnosis/staging and therefore may provide a reliable and cost-effective tool for the renal function assessment in diabetic patients.

A laboratory score at presentation to rule-out serious cardiac outcomes or death in patients presenting with symptoms suggestive of acute coronary syndrome

BACKGROUND

We evaluated whether a low high-sensitivity cardiac troponin (hs-cTn) cutoff combined with glucose, red cell distribution width (RDW), and the estimated glomerular filtration rate (eGFR) can be used to rule-out a serious cardiac outcome or death in patients presenting with symptoms suggestive of acute coronary syndrome (ACS).

METHODS

This was a prospective observational emergency department (ED) study enrolling consecutive patients presenting with symptoms suggestive of ACS (ClinicalTrials.gov: NCT01994577). The primary outcome was a 7-day composite of myocardial infarction, unstable angina, decompensated congestive heart failure, serious ventricular cardiac arrhythmia, or death. A laboratory score combining glucose, RDW, eGFR with hs-cTnT (Roche) or hs-cTnI (Abbott) was compared to hs-cTn alone using the limit of detection (LoD; hs-cTnT<5ng/l/hs-cTnI<2ng/l) as the cutoff. A benchmark of >99% sensitivity was used to assess the laboratory panel with hs-cTn versus the LoD alone to identify low-risk patients suitable for discharge.

RESULTS

A total of 1095 patients (n=267 composite-outcomes) had measurements of glucose, RDW, eGFR, hs-cTnT, and hs-cTnI at presentation. Applying the hs-cTn LoD alone as the cutoff missed 5 composite-outcomes (sensitivity=98.1%), however the addition of the laboratory panel to the hs-cTn LoD increased the sensitivity to >99% with approximately 10% of the population identified as low-risk. The percentage of low-risk patients was increased to 15% (1 composite-outcome missed) when employing a low measurable hs-cTnI cutoff with the laboratory panel (laboratory score<2 points).

CONCLUSION

A laboratory score with hs-cTn may identify low-risk patients suitable for ED discharge at presentation.

Evaluating renal function and age as predictors of amikacin clearance in neonates: model-based analysis and optimal dosing strategies

AIMS

We aimed to compare the performance of renal function and age as predictors of inter-individual variability (IIV) in clearance of amikacin in neonates through parallel development of population pharmacokinetic (PK) models and their associated impact on optimal dosing regimens.

METHODS

Amikacin concentrations were retrospectively collected for 149 neonates receiving amikacin (post-natal age (PNA) between 4-89 days). Two population PK models were developed in parallel, considering at least as predictors current body weight (WT), in combination with either creatinine clearance (CLcr ) or age descriptors. Using stochastic simulations for both renal function or age-based dosing, we identified optimal dosing strategies that were based on attainment of optimal peak- (PCC) and trough target concentration coverage (TCC) windows associated with efficacy and toxicity.

RESULTS

The CLcr and age-based population PK models both included current body weight (WT) on CL, central distribution volume and intercompartmental clearance, in combination with either CLcr or PNA as predictors for IIV of clearance (CL). The WT-CLcr model explained 6.9% more IIV in CL compared with the WT-PNA model. Both models successfully described an external dataset (n = 53) of amikacin PK. The simulation analysis of optimal dose regimens suggested similar performance of either CLcr or PNA based dosing.

CONCLUSION

CLcr predicted more IIV in CL, but did not translate into clinically relevant improvements of target concentrations. Our optimized dose regimens can be considered for further evaluation to optimize initial treatment with amikacin.