Creatinine Assay Research Articles

Calycosin attenuates renal ischemia/reperfusion injury by suppressing NF-κB mediated inflammation via PPARγ/EGR1 pathway.

Renal ischemia reperfusion injury (IRI) is a leading and common cause of acute kidney injury (AKI), and inflammation is a critical factor in ischemic AKI progression. Calycosin (CAL), a major active component of Radix astragali, has been reported to have anti-inflammatory effect in multiple organs. However, whether CAL can alleviate renal IRI and its mechanism remain uncertain. In the present study, a renal IRI model is established by bilateral renal pedicles occlusion for 35 min in male C57BL/6 mice, and the effect of CAL on renal IRI is measured by serum creatinine and pathohistological assay. Hypoxia/reoxygenation (H/R) stimulated human renal tubular epithelial cells HK-2 were applied to explore the regulatory mechanisms of CAL. Luciferase reporter assay and molecular docking were applied to identify the CAL’s target protein and pathway. In the mice with renal IRI, CAL dose dependently alleviated the renal injury and decreased nuclear factor kappa B (NF-κB) mediated inflammatory response. Bioinformatics analysis and experiments showed that early growth response 1 (EGR1) increased in mice with renal IRI and promoted NF-κB mediated inflammatory processes, and CAL dose-dependably reduced EGR1. Through JASPAR database and luciferase reporter assay, peroxisome proliferator-activated receptor γ (PPARγ) was predicted to be a transcription factor of EGR1 and repressed the expression of EGR1 in renal tubular epithelial cells. CAL could increase PPARγ in a dose dependent manner in mice with renal IRI and molecular docking predicted CAL could bind stably to PPARγ. In HK-2 cells after H/R, CAL increased PPARγ, decreased EGR1, and inhibited NF-κB mediated inflammatory response. However, PPARγ knockdown by siRNA transfection abrogated the anti-inflammation therapeutic effect of CAL. CAL produced a protective effect on renal IRI by attenuating NF-κB mediated inflammatory response via PPARγ/EGR1 pathway.

Prevalence, Characteristics and Outcome of Post-Operative Acute Kidney Injury in Cameroon: A Prospective Study in Three Hospitals in Douala

Objective: Post-operative acute kidney injury (AKI) is a frequent surgical complication. Data on this disorder are scare in our setting. We aimed to study the prevalence, characteristics and outcome of postoperative AKI in Cameroon. Methods: A prospective and analytical study from December 2020 to Mai 2021 including all consenting adults’ patients admitted in the departments of surgery, obstetrics/gynecology and intensive care unit (ICU) of 3 referral hospitals in Douala. For each patient, 3 serum creatinine assays were done on admission before the surgery, on days 2 and 7 after surgery. Postoperative AKI was defined and classified according to the modified KDIGO 2012 criteria. Outcome measure were kidney recovery at day 7 and mortality. Kidney recovery was total if serum creatinine on day 7 was less or equal to the preoperative value, partial if less than diagnostic value of day 2 but not the preoperative value and absent if creatinine on day 7 did not decrease or if the patient required dialysis. p <0.05 was considered significant. Result: Out of 203 patients included, 52 developed postoperative AKI, giving a prevalence of 26.6%. Mean age of AKI patients was 35.34 (13.74) years with 61.6% being (32/52) male; AKI stage 1 accounts for 55.7% (29/52), 19.3% (10/52) stage 2 and 25% (13/52) stage 3. AKI was functional in 61.5% (32/52) of cases mainly due to hypovolemia 42.5% (22/52) and sepsis 34.6% (18/52). For the 40 patients diagnosed on D2, kidney recovery was known in 75% (30/40); with 66.6% (20/30) total recovery, 23.4% (7/30) partial recovery and 10 % (3/30) without recovery. Mortality rate was 19% (10/52) mainly due to hemorrhagic shock. Intra operative hypotension (aOR: 6.09; CI: 1.4 - 26.33; p = 0.016) and dirty surgery (aOR: 6.22; CI: 1.35 - 28.75; p = 0.019) were factors associated with AKI. Conclusion: Postoperative AKI occurred in 1/4 of patients in our setting. It is mainly due to hypovolemia and sepsis, renal recovery and mortality were high.

An Endorsement of the Removal of Race From GFR Estimation Equations: A Position Statement From the National Kidney Foundation Kidney Disease Outcomes Quality Initiative

An Endorsement of the Removal of Race From GFR Estimation Equations: A Position Statement From the National Kidney Foundation Kidney Disease Outcomes Quality Initiative

Interaction of fluoride exposure and CREB1 gene polymorphisms on thyroid function in school-age children

To evaluate the effects of CREB1 gene polymorphisms and long-term exposure to fluoride on thyroid function of children. A total of 424 children (including 226 boys and 198 girls) aged 7-12 years old were enrolled in Kaifeng, China by cross-sectional study in 2017. The concentrations of urinary fluoride (UF) and creatinine (UCr) were measured using fluoride ion-selective electrode assay and creatinine assay kit (picric acid method), respectively. The concentration of UCr-adjusted UF (CUF) was calculated. Children were divided into high fluoride exposure group (HFG, CUF >1.41mg/L) and low fluoride exposure group (LFG, CUF ≤1.41mg/L) according to the median concentration of CUF (1.41mg/L). The serum thyroid-stimulating hormone (TSH), total triiodothyronine (TT3) and total thyronine (TT4) levels were detected by the radiation immunoassay. The B-mode ultrasound was performed to test the thyroid volume (Tvol). Genotyping of CREB1 gene was conducted by a custom-by-design 48-plex SNPscan™ Kit. Associations between CUF concentration, CREB1 single nucleotide polymorphisms (SNPs) and thyroid function were assessed by multiple linear regression models. Negative and positive associations between serum TT4 level (β=-0.721, 95%CI: -1.209, -0.234) and Tvol (β=0.031, 95%CI: 0.011, 0.050) and CUF concentration were observed respectively. Children carrying CREB1 rs11904814 TG and rs2254137 AC genotypes had lower TT3 levels (P<0.05). Children in HFG carrying rs11904814 TT, rs2253206 GG genotypes and rs6740584 C allele easily manifested lower serum TT4 levels (P<0.05). Moreover, interactions between excessive fluoride exposure and CREB1 SNPs on Tvol were observed, and the interaction among different loci of CREB1 gene could modify serum TT3 level (P<0.05, respectively). Fluoride could alter children's serum TT4 levels and Tvol. Interactions between fluoride exposure and CREB1 polymorphisms may modify thyroid volume of children.

Do methylenetetrahydrofolate dehydrogenase, cyclohydrolase, and formyltetrahydrofolate synthetase 1 polymorphisms modify changes in intelligence of school-age children in areas of endemic fluorosis?

Background:Excessive exposure to fluoride can reduce intelligence. Methylenetetrahydrofolate dehydrogenase, cyclohydrolase, and formyltetrahydrofolate synthetase 1 (MTHFD1) polymorphisms have important roles in neurodevelopment. However, the association of MTHFD1 polymorphisms with children's intelligence changes in endemic fluorosis areas has been rarely explored.Methods:A cross-sectional study was conducted in four randomly selected primary schools in Tongxu County, Henan Province, from April to May in 2017. A total of 694 children aged 8 to 12 years were included in the study with the recruitment by the cluster sampling method. Urinary fluoride (UF) and urinary creatinine were separately determined using the fluoride ion-selective electrode and creatinine assay kit. Children were classified as the high fluoride group and control group according to the median of urinary creatinine-adjusted urinary fluoride (UFCr) level. Four loci of MTHFD1 were genotyped, and the Combined Raven's Test was used to evaluate children's intelligence quotient (IQ). Generalized linear model and multinomial logistic regression model were performed to analyze the associations between children's UFCr level, MTHFD1 polymorphisms, and intelligence. The general linear model was used to explore the effects of gene-environment and gene-gene interaction on intelligence.Results:In the high fluoride group, children's IQ scores decreased by 2.502 when the UFCr level increased by 1.0 mg/L (β = −2.502, 95% confidence interval [CI]:−4.411, −0.593), and the possibility for having “excellent” intelligence decreased by 46.3% (odds ratio = 0.537, 95% CI: 0.290, 0.994). Children with the GG genotype showed increased IQ scores than those with the AA genotype of rs11627387 locus in the high fluoride group (P < 0.05). Interactions between fluoride exposure and MTHFD1 polymorphisms on intelligence were observed (Pinteraction < 0.05).Conclusion:Our findings suggest that excessive fluoride exposure may have adverse effects on children's intelligence, and changes in children's intelligence may be associated with the interaction between fluoride and MTHFD1 polymorphisms.

Resolving icteric interference by a novel photoisomerization device: Bilibox

Icterus, a phenomenon caused by bilirubin elevation in the blood, is a common endogenous interference in chemistry testing, occurring either spectrally or through chemical reactivity with assay reagents. Often, laboratories have few options other than to dilute or reject samples exceeding icteric thresholds. However, recent studies have optimized in vitro photoisomerization of bilirubin to a 17-minute bilirubin half-life using 500 nm light at 37 °C. Using an enzymatic creatinine assay as a model, due to its prevalence in routine laboratory testing and susceptibility to icteric interference, our study explores the usage of in vitro photoisomerization by replicating these conditions in a device, the Bilibox, as means of resolving icterus in laboratory testing.Left-over icteric and non-icteric clinical samples, collected by lithium heparin vacutainer (n = 10), were analyzed for baseline creatinine, diluted creatinine (1:4 0.9 % NaCl), total bilirubin, direct bilirubin, and hemolysis, icterus and lipemia (HIL) indices. Samples were then placed in the Bilibox in two intervals of 30 min with repeat measurements of the aforementioned analytes.On average, icteric-index, total bilirubin (TBIL), and direct bilirubin (DBIL) decreased by 33.5, 39.1 and 39.9 % respectively following 30 min of Bilibox treatment; and by 47.6 %, 63.7 % and 59.8 % following 60 min. The average percent difference between the pre-exposure diluted and undiluted creatinine was 5.8 %, demonstrating the icterus interference. Following Bilibox treatment, the difference between undiluted (post-exposure) and diluted (pre-exposure) creatinine decreased to 0.02 % (p = 0.0232) and 2.2 % (p = 0.0021) at 30 and 60 min of treatment respectively, demonstrating resolution of interference. Consequently, photoisomerization can be utilized as an additional and reasonably quick method for resolving icterus when dilutional methods cannot be applied.

Combination of Ashwagandha Water Extract and Intermittent Fasting as a Therapy to Overcome Cisplatin Resistance in Breast Cancer: An in vitro and in vivo Study.

Breast cancer is considered a universal public health dilemma in women. Due to the high toxicity and low selectivity of conventional anticancer therapies, there is a growing trend of using plant-derived natural products in cancer prevention and therapy. Ashwagandha (Withania somnifera, WS) has been used in the Mediterranean region and Ayurvedic medicine for millennia as a functional food and a medicinal plant with anticancer activity. Besides, intermittent fasting (IF) has been engaged recently in cancer treatment. Hence, the combination of WS and IF provides possible solutions to treat cancer and reduce chemoresistance when combined with chemotherapy. In this study, WS root (WSR), IF, and cisplatin were tested on cisplatin-sensitive (EMT6/P) and cisplatin-resistant (EMT6/CPR) mouse mammary cell lines. The phytochemical content of the WSR extract was analyzed using liquid chromatography–mass spectrometry (LC-MS) analysis. Antiproliferative and apoptotic effects were assessed for WSR extract, cisplatin, and their combination in vitro using [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide] (MTT) and caspase-3 assays. An in vivo study was used to assess the effect of WSR extract, IF, cisplatin, and their combinations in mice inculcated with EMT6/P and EMT6/CPR cells. The safety profile was also investigated using liver enzymes and creatinine assays. In vitro, WSR extract and cisplatin had a synergistic effect in both cell lines. The same combination induced an apoptotic effect higher than the single treatment in both cell lines. In vivo, several combinations of WSR extract, IF, or cisplatin caused significant tumor size reduction and improved the cure rate in mice implanted with EMT6/P and EMT6/CPR cell lines. IF-treated groups showed a significant reduction in serum glucose and an elevation in β-hydroxybutyrate (BHB) levels. In the safety profile, WSR extract, IF, and their combinations were safe. Overall, the combination of WSR extract and IF provides a promising solution for breast cancer treatment besides cisplatin by reducing the proliferation of cancer cells through induction of apoptosis. Moreover, they minimize cisplatin toxicity to the liver and kidney.

International consensus guideline for anticancer drug dosing in kidney dysfunction (ADDIKD): A standardized approach to assessing kidney function in cancer patients and its application to anticancer drug dosing.

e13518 Background: Anticancer drug dosing recommendations in kidney dysfunction are often empirical, based on non-standardised creatinine assays calculated via the Cockcroft-Gault equation, and lack applicability to globally accepted kidney dysfunction classifications. ADDIKD aims to provide a standardised approach to assessing kidney function in cancer patients, and to apply evidence and consensus-based recommendations to anticancer drug dosing in kidney dysfunction. Methods: An expert international multidisciplinary working group was established to develop anticancer drug dosing recommendations. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to critically appraise the quality and strength of evidence and formulate recommendations. The working group participated in workshops to achieve &gt; 80% consensus for a standardised approach to assessing and classifying levels of kidney function, its application to anticancer drug dosing in kidney dysfunction, and dosing recommendations for individual drugs. Upcoming public consultation will refine these recommendations and facilitate acceptance as an international benchmark. Results: Three key recommendations formed the basis of ADDIKD: Application of estimated glomerular filtration rate via the Chronic Kidney Disease-Epidemiology Collaboration equation (eGFRCKD-EPI) to guide the assessment of kidney function, except where directly measured glomerular filtration rate (mGFR) is clinically necessary. Where the anticancer drug dose is dependent on kidney function and mGFR is not clinically necessary, eGFRCKD-EPI is suggested to guide dosing. Application of the Kidney Disease Improving Global Outcomes (KDIGO) Chronic Kidney Disease categories to guide stepwise dose adjustments of anticancer drugs in kidney dysfunction. A review of 2263 published articles and 177 registered product information monographs enabled 127 GRADE assessments by the working party, resulting in evidence and consensus-based dosing recommendations for 59 anticancer drugs. 'Quick reference’ dosing tables incorporated a traffic light system for alerting clinicians to caution around levels of kidney function and specific patient risk factors for consideration. Conclusions: eGFRCKD-EPI is the most accurate and convenient method for assessing kidney function in diverse populations (including cancer patients) and accounts for the standardisation of the creatinine assay. ADDIKD’s expert acceptance of this standardised approach, together with anticancer drug dosing recommendations in kidney dysfunction, provides a practical tool to establish clinically relevant dosing in this patient population.

Levamisole causes a transient increase in plasma creatinine levels but does not affect kidney function based on cystatin C

BackgroundIn pediatric patients treated with levamisole to prevent relapses of idiopathic nephrotic syndrome (INS), a transient and non-progressive rise in creatinine levels has been observed. It has been suggested that levamisole affects tubular secretion of creatinine. However, other potential mechanisms — nephrotoxicity and interference with the analytical assay for creatinine — have never been thoroughly investigated.MethodsIn three steroid-sensitive nephrotic syndrome (SSNS) patients with elevated plasma creatinine levels, treated with levamisole 2.5 mg/kg every other day, serum cystatin C was determined. The glomerular filtration rate (GFR) was estimated using the full age spectrum for creatinine and the full age spectrum for cystatin C equations. Interference of levamisole with the enzymatic creatinine assay was tested using spare human plasma of different creatinine concentrations spiked with levamisole (4, 20, and 100 µM).ResultsThree patients who received levamisole with elevated plasma creatinine levels had normal serum cystatin C levels and corresponding estimated GFR. There was no assay interference.ConclusionLevamisole increases plasma creatinine levels, which is most probably due to impaired tubular secretion of creatinine since there was no assay interference and patients had normal eGFR based on serum cystatin C. However, interference of metabolites of levamisole could not be excluded. To monitor GFR, cystatin C in addition to creatinine should be used and be measured before and during levamisole use.

IDF21-0124 Relationship between Serum Zinc Status and Diabetic Nephropathy in Algerian Patients with Type 2 Diabetes

Background: Diabetic nephropathy is a microvascular complication associated with diabetes that causes the kidneys to slowly deteriorate, leading to end-stage renal disease. Nephropathy associated with diabetes has been attributed to oxidative stress. Chronic zinc deficiency generally results in an increased sensitivity to the effects of oxidative stress. Zinc deficiency is often seen in diabetic patients. This alteration in zinc status appears to be involved in the development of microvascular complications of diabetes. Aim: The objective of this study will be to explore the relationship between zinc status and the progression of nephropathy in type 2 diabetes. Method: The study involved 80 normotensive diabetic patients with positive microalbuminuria and 60 healthy non-diabetic subjects of corresponding age. For all subjects, a serum zinc assay was performed on the ICE 3300 atomic absorption spectrometer from Thermo Fisher, a serum creatinine assay on Cobas 501 from Roche Diagnostic with evaluation of GFR, as well as a microalbuminuria assay. on the DCA Vantage from Siemens. Results: Serum zinc levels were low (p <0.001) in diabetic patients compared to non-diabetic control subjects. Elevated levels of microalbuminuria (p <0.001) were observed in diabetic patients with low serum zinc levels compared to those with normal serum zinc levels. Serum zinc level in diabetic patients was inversely correlated with serum creatinine (r = −0.51, p <0.001), microalbuminuria (r = −0.587, p <0.001) and positively with GFR (r = 0.24, p <0.01). Discussion: The results of our study support the observation that diabetes affects zinc status with a significant decrease in serum zinc levels at the onset of diabetic complications. During progression to the stages of diabetic nephropathy, morphological and structural changes occur in the glomerular and basal membrane of the kidneys, hyperfiltration, thickening of the glomerular basement membrane. All of these changes will cause albumin with trace metals to leak into the urine. Therefore, the hypozincemia seen in diabetics can be attributed to hyperzincuria. The results of this study are consistent with results reported by others.

Using Pen-Side Measurable Blood Parameters to Predict or Identify Dystocic Lambing Events.

Simple SummaryProlonged or non-progressive labour is the greatest risk factor for loss of newborn lambs in Australia and poses significant welfare and economic concerns worldwide. In this study, we set out to investigate whether pen-side technology could be used to predict which ewes would be at risk of prolonged labour. In our pilot trial, we found potentially useful markers. We next developed a sampling protocol by looking at changes in candidate markers over time in normal lambing events. Finally, we searched for blood markers that could distinguish between normal and difficult lambing events, sampling pre-birth (estimated one week before birth), at birth (within 3 h) and post-birth (16–26 h). Possible predictors of lambing difficulty were chloride, haematocrit and haemoglobin, sampled one week before birth; creatinine, sampled at birth; and acid–base related parameters after birth. In conclusion, we found that pen-side analysis of blood markers showed promise in identifying dystocic lambing events. More information is required to decide whether pen-side diagnostics could be useful to identify and predict dystocic lambing in the future.Dystocia is the greatest contributor to neonatal lamb mortality in Australia and poses significant welfare and economic concerns worldwide. In this study, we set out to investigate whether pen-side analysis technology could be employed to detect blood parameters predictive of dystocic labour events in sheep. In a pilot trial, we collected and analysed blood samples in pen-side assays for glucose, lactate, pH, pCO2, pO2, base excess, HCO3, TCO2, sO2, lactate, sodium, potassium, chloride, calcium, urea nitrogen, creatinine, haematocrit, haemoglobin and anion gap. From the pilot data, we identified creatinine, TCO2, chloride and calcium as potentially useful markers. To develop a time course and to establish variability of the selected blood parameters, a time series of samples was collected from 12 ewes, from mid-gestation to 48 h after birth. For the main trial, blood samples were collected at mid- and late gestation for glucose determination and for the full set of blood parameters at three time points before, at and after birth. Possible predictors of lambing difficulty were chloride, haematocrit and haemoglobin, sampled one week before birth; creatinine, sampled at birth; and blood pH and base excess after birth. In conclusion, we found that pen-side analysis of blood markers showed promise in identifying dystocic lambing events.

Analytical performance evaluation of different test systems on serum creatinine assay.

BackgroundSerum creatinine (SCr) is a useful diagnostic marker for the assessment of renal function. Accurate quantitation of SCr is clinically important in calculation of glomerular filtration rate (GFR).MethodTo confirm whether there are differences in SCr between enzymatic kits of different manufacturers, the analytical performance of the matched and open test system in the measurement of SCr was evaluated. The analytical performance evaluation was conducted according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. Precision, accuracy, linearity, dilution, lower limit of measurement and analytical interference were studied between the two test systems.ResultsThe performance of SCr from the open test system was in compliance with the matched test system with good precision, accuracy, and linearity. In presence of most common interferents, both test systems could lead to accurate creatinine results except for the existence of specified drugs. For dobutamine, the open test system showed better anti‐interference performance than the matched system.ConclusionThis study provides referable opinions for clinical laboratory selection on the test system and a framework for future analogous studies based on different test systems.

Prévalence de la maladie rénale chronique à Antananarivo, Madagascar

IntroductionChronic kidney disease is defined as an inability of the kidney to perform its normal functions and which persists beyond three months. Nowadays, the estimated glomerular filtration rate based on plasmatic creatinine level remains the gold standard to assess renal function. In Madagascar, we miss national data concerning the epidemiology of chronic kidney disease probably due to the complexity of carrying out the serum creatinine assays. The recent availability of creatinometer using a creatinine strip test with capillary creatinine facilitated the determination of the creatinine level in epidemiological study. Patients and methodsThis simple technique allowed us to plan a pilot study in Antananarivo, the capital of Madagascar. The main objective was to assess the prevalence of chronic kidney disease determined from capillary creatinine level. The secondary objective was to determine the factors associated with chronic kidney disease in Madagascar. It is an analytical cross-sectional study over a period of three months. Chronic kidney disease is defined as a decrease of the glomerular filtration rate of capillary creatinine less than 60mL/min/1.73m2 and calculated with Chronic Kidney Disease Epidemiology formula (CKD-EPI). The minimum number of studied population has been assessed and settled at 210 people. Cluster sampling was performed for randomization of participants. ResultsAt the end of the study, 210 people were randomized for screening. The average age was 40 years old with 14.9 as standard deviation. The sex ratio (male/female) was 1.76. The prevalence of chronic kidney disease was 13.8% with extreme values of 9,1 and 18.5. With chronic kidney disease, high blood pressure (hypertension) and diabetes were found respectively in 41.3 and 17.2%. Chronic kidney disease affected mainly in 72.4% of population aged 25 to 54 years old. ConclusionThis is the first study in Africa to screen chronic kidney disease using a creatinine strip test. This prevalence is relatively different compared to other African countries. The limits of the study are the absence of a subsequent control and/or double control of the creatinine, which definitively confirms the chronicity of kidney disease, the absence evaluation of the urinary sediments to determine proteinuria. Nevertheless, the results of our study can be used as data awaiting the results of a multicenter studies. To determine the national prevalence of chronic kidney disease, screening in the six provinces is currently in progress.

Tubular phosphate handling: references from child to adulthood in the era of standardized serum creatinine.

The assessment of phosphate homeostasis in clinical practice relies not only on circulating phosphate levels but also on phosphate tubular reabsorption, ideally assessed using the tubular maximum phosphate reabsorption per glomerular filtration rate (TmP/GFR). TmP/GFR reference values were established before the onset of isotope-dilution mass spectrometry-standardized (IDMS) creatinine assays and thus need to be updated. Our objective is to provide reference values for TmP/GFR from childhood to adulthood, using the gold-standard of GFR assessment and IDMS-standardized creatinine values. We retrospectively analysed all the inulin and iohexol clearances [measured glomerular filtration rate (mGFR)] performed in children and in adults screened for a living-donation in our unit since the beginning of IDMS-creatinine assays. TmP/GFR was calculated on a fasting sample, using the conventional formula without correction for tubular reabsorption of phosphate (TRP) in subjects below 19 years of age. A total of 2051 subjects (1711 children, 340 adults), aged from 1.9 to 73.4 years with normal GFR, normal phosphate and normal calcium levels, were included for TmP/GFR analysis. As expected, there was a progressive decrease along puberty in both genders of plasma phosphate and TmP/GFR, the decrease occurring earlier in girls. After the age of 19 years, there was a stabilization of plasma phosphate and TmP/GFR levels until the age of 55 years, phosphate levels and TmP/GFR being slightly lower in men than in women. We present the largest cohort describing TmP/GFR reference values in the era of IDMS-standardized creatinine assays. We believe that these data will help physicians to better diagnose and manage patients with abnormal phosphate metabolism in daily clinical routine.

On-line ‘protein shaker’: A multicommutated flow analysis system for fluorometric creatinine determination in deproteinized serum

A fully mechanized multicommutated flow analysis (MCFA) system for fluorometric determination of creatinine in serum samples is introduced in this paper. The flow system was constructed with microsolenoid pumps and valves and with a 3D-printed flow cell. Fluorometric assay relied on creatinine reaction with 3,5-dinitrobenzoic acid and hydrogen peroxide in an alkaline environment. To overcome significant interference from protein, a flow reactor for serum deproteinization was designed and implemented in the flow system. The deproteinization was carried out by precipitation with trichloroacetic acid and the addition of sodium chloride facilitated the precipitate sedimentation. The supernatant representative sample was pumped out and subjected to fluorometric creatinine assay. The obtained linear range was from 1.6 to 500 μmol L−1 and the precision, expressed as RSD, was below 3%. The proposed MCFA system was used to determine creatinine concentration in control serum samples. The results obtained with flow deproteinization correlated well with results obtained with conventional deproteinization (y = (0.91 ± 0.09) x + (37 ± 28)) with Pearson's r 0.979.

Amperometric biosensors for L-arginine and creatinine assay based on recombinant deiminases and ammonium-sensitive Cu/Zn(Hg)S nanoparticles

There are limited data on amperometric biosensors (ABSs) based on deiminases that produce ammonium as a byproduct of enzymatic reaction. The most frequently proposed biosensors utilizing such a mode are based on potentiometric transducers, which contain at least two enzymes in the bioselective layer; this complicates the procedure and increases the cost of analysis. Thus, the construction of a one-enzyme ABS is a practical problem. In our manuscript ABSs for the direct measurement of creatinine (Crn) and l-arginine (Arg), based on the recombinant bacterial creatinine deiminase (CDI) and arginine deiminase (ADI), are described. To choose the best chemosensor on ammonium ions, a number of nanoparticles (NPs) were synthesized and characterized using cyclic voltammetry. Hybrid Cu/Zn(Hg)S-NPs, having a good selectivity and an extremely high sensitivities towards ammonium ions (5660 A M−1 m−2 at +170 mV and 1870 A M−1 m−2 at −300 mV, respectively), was selected for the development of deiminase-based ABSs. The novel biosensors exhibited very high sensitivities (2660 A M−1 m−2 to Crn for CDI-ABS; 1570 A M−1 m−2 to Arg for ADI-ABS), broad linear ranges, low limits of detection, satisfactory storage stabilities and good selectivities towards natural substrates. The constructed CDI-ABS and ADI-ABS were tested on real samples of biological fluids and juices for Crn and Arg assay, respectively. High correlations of the obtained results with the reference methods were demonstrated for the target analytes.

Prévalence de la maladie rénale chronique en France, Esteban 2014–2016

BackgroundThe epidemiology of chronic kidney disease remains poorly described in France despite its burden. The objective of our study was to provide an estimate of the prevalence of chronic kidney disease stades 3–5 (without replacement therapy) in France. MethodThe data come from the Esteban study carried out in France between 2014 and 2016 on a representative sample of the French population. This study included 3,021 adults between 18 and 74 years old. Of these, 2422 adults (80.2%) had serum creatinine assay and were included in this analysis. Renal function was estimated by calculating glomerular filtration rate using the Chronic kidney disease epidemiology collaboration (CKD-Epi) and European Kidney function consortium (EKFC) equations. ResultsThe means glomerular filtration rate in our population were respectively 97.5 and 89.0 mL/min/1.73 m2 with the CKD-EPI and EKFC equations. The prevalence of chronic renal failure, defined by a glomerular filtration rate less than 60 mL/min/1.73 m2 was 1.5% with the CKD-EPI formula and 2.1% with the EKFC formula in adults aged 18 to 74 years. The prevalence was higher in women than in men and increased with age, reaching 6.5% and 9.9% in 65–74 years with the CKD-EPI and EKFC equations, respectively. After extrapolation to the French population, the number of adults with chronic kidney disease stades 3–5 without renal replacement therapy was around 1.6 million. ConclusionIn France, the prevalence of chronic kidney disease stades 3–5 without renal replacement therapy was between 1.5 and 2.1% of the adult population aged 18 to 74.

Lithium heparin interference in the Abbott enzymatic creatinine assay: the significance of under-filled tubes.

Spuriously high results using the Abbott Architect enzymatic creatinine assay were noted to be particularly associated with very small sample volumes. This led us to query the effect of under-filling lithium heparin tubes on the measured enzymatic creatinine result. Blood was provided by 5 laboratory personnel and then decanted into 5 x1.2mL Sarstedt S-Monovette tubes, giving final blood volumes of 200, 400, 600, 800 and 1200μL. Plasma was analysed using Abbott Architect Jaffe, enzymatic creatinine, Beckman Coulter (AU500) enzymatic creatinine and Roche (Cobas c702) enzymatic creatinine assays. Saline was also added to Sarstedt 1.2mL and Teklab 2mL tubes and analysed using the Abbott Jaffe and enzymatic creatinine methods. Increasing degrees of under-fill were associated with greater over-estimation of creatinine using the Abbott enzymatic assay, but no difference was noted using Jaffe methodology on the same platform or enzymatic assays provided by Roche or Beckman. On average, creatinine was 40.6% (+27.7μmol/L) higher when only 200μL of blood was present in the tube. Small volumes of saline added to lithium heparin tubes measured significant creatinine concentrations using the Abbott enzymatic method. Lithium heparin directly interferes in the Abbott Architect enzymatic creatinine assay. Under-filling lithium heparin tubes can lead to clinically significant over-estimation of creatinine results by this assay. Users of this assay should be aware of the potential for spurious results in small sample volumes collected into lithium heparin tubes and implement robust procedures for identifying and reporting results on these samples.

Recent Trends in Creatinine Assays in Korea: Long-Term Accuracy-Based Proficiency Testing Survey Data by the Korean Association of External Quality Assessment Service (2011-2019).

BackgroundAccurate serum creatinine (Cr) concentration measurement is essential for evaluating kidney function. In 2011, the Korean Association of External Quality Assessment Service (KEQAS) launched an accuracy-based Cr proficiency testing (ABCr PT) survey. We analyzed long-term data of the KEQAS ABCr PT survey collected between 2011 and 2019 to assess recent trends in Cr assays in Korea.MethodsThe ABCr PT survey including three commutable fresh-frozen serum samples was performed twice a year. The target Cr concentration was assigned using isotope-dilution mass spectrometry. We analyzed data obtained from the participating laboratories, calculated the yearly bias, and evaluated bias trends for the major reagents and instruments. Outliers were excluded from all analysis.ResultsThe mean percentage bias based on the total data of all participating laboratories was 10.8% in the 2011-A survey and 0.2% in 2019-B survey. Bias for the major reagents and instruments differed depending on the manufacturer. Enzymatic assays generally showed desirable bias ranging from –3.9% to 3.2% at all Cr concentrations and lower interlaboratory variability than non-enzymatic assays (enzymatic vs. non-enzymatic, 3.3%–7.2% vs. 6.3%–9.1%).ConclusionsAlthough the mean percentage bias of Cr assays tends to decrease over time, it is necessary to continuously strive to improve Cr assay accuracy, especially at low concentrations.

AACC Guidance Document on Laboratory Investigation of Acute Kidney Injury.

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. 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. 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.