scholarly journals Accuracy Evaluation of a Tetrabromophenolphthalein Ethyl Ester Colorimetric Assay for Urinary Albumin

2019 ◽  
Vol 4 (2) ◽  
pp. 201-213
Author(s):  
Alyse D Krausz ◽  
Rajan Dewar ◽  
Mark A Burns
Keyword(s):  
Ethyl Ester ◽  
Colorimetric Assay ◽  
Point Of Care ◽  
Urinary Albumin ◽  
Urine Samples ◽  
Albumin Concentration ◽  
Accuracy Evaluation ◽  
Standard Samples ◽  
Creatinine Concentration ◽  
3D Surface

Abstract Background The tetrabromophenolphthalein ethyl ester (TBPE) assay has been used to quantify urinary albumin in point-of-care devices. We assessed the accuracy of this TBPE assay for urinary albumin through comparison with an established immunoturbidimetric method (ADVIA 1800 Chemistry System, Siemens). Methods We developed a TBPE assay protocol to quantify albumin in the range associated with microalbuminuria (0–200 mg/L). The Jaffe reaction and a 3-dimensional (3D) surface were used to compensate for creatinine interference. Spiked simulated urine samples and patient samples were used to compare the TBPE assay with the immunoturbidimetric method. Multiple linear regression was used to analyze factors that could account for discrepancies between the 2 methods. Results We found that creatinine interfered with the TBPE assay. To compensate, a 3D surface was successfully used to quantify albumin in spiked deionized water and simulated urine samples. In spiked simulated urine samples, the immunoturbidimetric method underestimated the albumin concentration by 2 to 45 mg/L, and the TBPE assay overestimated it by 9 to 82 mg/L. In patient samples, the albumin concentrations measured with the TBPE assay and the immunoturbidimetric method differed by an average of 184 mg/L. Conclusions The TBPE assay is a function of the creatinine concentration, and a 3D surface can be used to provide accurate albumin concentrations for standard samples. The corrected TBPE method and the immunoturbidimetric method deviated from known concentrations of spiked samples. Further investigation and comparisons with a third albumin measurement method, such as LC-MS/MS, are necessary before conclusions on the accuracy of the TBPE assay can be made.

A specific immunoassay for detection of feline kidney injury molecule 1

2018 ◽  
Vol 21 (12) ◽  
pp. 1069-1079
Author(s):  
S Karlyn Bland ◽  
Mary Ellen Clark ◽  
Olivier Côté ◽  
Dorothee Bienzle
Keyword(s):  
Fusion Protein ◽  
Point Of Care ◽  
Kidney Tissue ◽  
Kidney Injury ◽  
Urine Samples ◽  
Urethral Obstruction ◽  
Preliminary Evaluation ◽  
Creatinine Concentration ◽  
Kidney Injury Molecule 1 ◽  
Patient Side

Objectives The aim of this study was to design and carry out a preliminary evaluation of a urine point-of-care test for kidney injury molecule 1 (KIM-1) in healthy and diseased cats. Methods Part of the feline KIM-1 gene was amplified, ligated into a plasmid with a signal peptide and monomeric human IgGFc, and transfected into a mammalian cell line. Supernatant was purified and tested for the fusion protein by gel electrophoresis and Western blot. Mice were immunized three times with purified proteins, and hybridomas were generated from splenocytes. Antibodies were tested by ELISA for detection of recombinant KIM-1 and naturally occurring KIM-1 in disease-state urine. Next, a lateral flow assay (LFA) with capture and detection antibodies was constructed, and tested with 34 urine samples from healthy and diseased cats. Antibodies were also tested for reactivity with formalin-fixed paraffin-embedded kidney tissue. Results Three antibodies were assessed. Antibodies detected between 0.4 and 60 ng/ml feline KIM-1 fusion protein in the LFA. Urine samples from healthy cats yielded faint bands in the LFA corresponding to optical density (OD) values of 4.8–8.8. Samples from cats with suspected or confirmed acute kidney injury (AKI) had OD values ranging from 1.6–20.5. Urine KIM-1 varied over multiple days in cats with sepsis or urethral obstruction despite normalizing serum creatinine concentration. In tissue sections, KIM-1 antibodies labeled tubular cells with morphological features of injury. Conclusions and relevance A practical patient-side assay for detection of KIM-1 in feline urine has been developed. Preliminary results show marked though transient increases in cats with sepsis and urethral obstruction-associated AKI, and expression in injured tubules. Although initial data indicating that the LFA is sensitive and specific for KIM-1 in cats with AKI are promising, values associated with different types of injury, urine collection, urine storage and specific gravity need to be investigated.

scholarly journals POS-417 NOVEL POINT-OF-CARE DEVICE – SCINTIGLO® – FOR QUANTITATIVE ESTIMATION OF URINARY ALBUMIN

2021 ◽  
Vol 6 (4) ◽  
pp. S179-S180
Author(s):  
R. Sreedhara ◽  
M.K. Pal ◽  
N. Pal ◽  
V. Jain ◽  
S. Jain ◽  
...  
Keyword(s):  
Quantitative Estimation ◽  
Point Of Care ◽  
Urinary Albumin

scholarly journals A Smartphone Camera Colorimetric Assay of Acetylcholinesterase and Butyrylcholinesterase Activity

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1796
Author(s):  
Miroslav Pohanka ◽  
Jitka Zakova
Keyword(s):  
Limit Of Detection ◽  
Colorimetric Assay ◽  
Point Of Care ◽  
Specific Treatment ◽  
Point Of Care Testing ◽  
Analytical Instruments ◽  
Colorimetric Test ◽  
3D Printed ◽  
Butyrylcholinesterase Activity ◽  
Additional Education

Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) can serve as biochemical markers of various pathologies like liver disfunction and poisonings by nerve agents. Ellman’s assay is the standard spectrophotometric method to measure cholinesterase activity in clinical laboratories. The authors present a new colorimetric test to assess AChE and BChE activity in biological samples using chromogenic reagents, treated 3D-printed measuring pads and a smartphone camera as a signal detector. Multiwell pads treated with reagent substrates 2,6-dichlorophenolindophenyl acetate, indoxylacetate, ethoxyresorufin and methoxyresorufin were prepared and tested for AChE and BChE. In the experiments, 3D-printed pads containing indoxylacetate as a chromogenic substrate were optimal for analytical purposes. The best results were achieved using the red (R) channel, where the limit of detection was 4.05 µkat/mL for BChE and 4.38 µkat/mL for AChE using a 40 µL sample and a 60 min assay. The major advantage of this method is its overall simplicity, as samples are applied directly without any specific treatment or added reagents. The assay was also validated to the standard Ellman’s assay using human plasma samples. In conclusion, this smartphone camera-based colorimetric assay appears to have practical applicability and to be a suitable method for point-of-care testing because it does not require specific manipulation, additional education of staff or use of sophisticated analytical instruments.

scholarly journals Assessment of Micral-Test Microalbuminuria Test Strip in the Laboratory and in Diabetic Outpatients

1992 ◽  
Vol 29 (1) ◽  
pp. 96-100 ◽  
Author(s):  
Denis R Jury ◽  
Donald J Mikkelsen ◽  
Deborah Glen ◽  
Peter J. Dunn
Keyword(s):  
Screening Method ◽  
Urine Osmolality ◽  
Test Strip ◽  
Albumin Concentration ◽  
Creatinine Concentration ◽  
Urine Albumin ◽  
Low Concentrations ◽  
Colour Development ◽  
The Stability ◽  
Sodium And Potassium

We have evaluated a semi-quantitative dry immunochemical screening method (Micral-Test) for the detection of low concentrations of albumin in urine. The stability of Micral-Test strips on storage was good, especially with regard to temperature, light and humidity. Changes in urine osmolality (urea and creatinine concentration), pH and sodium and potassium concentration did not have a significant analytical effect on the Micral-Test measurement; extremes of temperature altered the rate of colour development. The depth of dipping the strip into the sample and the timing of reading colour development were critical. We measured the albumin concentration in 184 urine samples from diabetic outpatients by the Micral-Test and by our in-house immunoturbidimetric method; a Micral-Test result of 20 mg/L had a sensitivity of 91% and specificity of 97% to predict a discriminating urine albumin concentration > 30 mg/L by the in house method. The Micral-Test is suitable for use by non-laboratory personnel and is capable of producing analytically acceptable results for use in diabetes clinics and by general practitioners.

Comparative study of i-SENS glucometers in neonates using capillary blood samples

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ha Nui Kim ◽  
Soo-Young Yoon
Keyword(s):  
Reference Values ◽  
Point Of Care ◽  
Evaluation Process ◽  
Capillary Blood ◽  
Performance Criteria ◽  
Accuracy Evaluation ◽  
Blood Samples ◽  
Average Reference ◽  
Error Grid ◽  
Accuracy Performance

Abstract Objectives The accuracy of point-of-care blood glucometers in the detection and evaluation of neonatal hypoglycemia is a concern. This study compared the performance of three i-SENS glucometers with that of the YSI 2300 STAT Plus Analyzer, which was used as a reference. Methods The leftover neonatal capillary blood samples of 319 patients were used in this study. The evaluation process and accuracy performance criteria were based on the International Organization for Standardization 15197:2013 guidelines. The evaluation involved three i-SENS glucometers (BAROzen H Expert plus, CareSens PRO, and CareSens H Beat) and the ACCU-CHEK® Inform II glucometer. Results The accuracy evaluation yielded acceptable results as follows: a) 100 and 100% for BAROzen H Expert plus; 99.8 and 100% for CareSens PRO; 98.7%, and 97.2% for CareSens H Beat glucometers were within the range of ±0.8 mmol/L (15 mg/dL) and ±15% of the average reference values at glucose concentrations <5.55 mmol/L (100 mg/dL) and ≥5.55 mmol/L (100 mg/dL), respectively, and b) all estimated glucose values (100%) were within the zones A and B of Consensus Error Grid for all three i-SENS glucometers. There was good correlation between the glucose values estimated by the glucometers and the reference values (R>0.990). Conclusions This study demonstrated that i-SENS glucometers exhibit acceptable performance and can be used as effective point-of-care devices in neonates.

scholarly journals The relation between oestrus signs and probability of ovulation at dubious oestrus in gilts.

1989 ◽  
Vol 37 (2) ◽  
pp. 165-168
Author(s):  
H. Boer ◽  
L.A. den Hartog ◽  
K. Boode ◽  
H.A.M. van der Steen ◽  
W.C. Melger ◽  
...  
Keyword(s):  
Urine Samples ◽  
Creatinine Concentration ◽  
Urine Creatinine

680 gilts were studied from 168 days of age. Urine samples were collected 10-12 days after a "dubious" 1st oestrus. Of 188 gilts showing a dubious 1st oestrus, 14 produced urine samples with a creatinine concentration of 0.25 mg/ml, 99 and 75 samples had a high and a low pregnanediol concentration resp. It was concluded that 99 (57%) of gilts had an ovulatory 1st oestrus as indicated by high urine creatinine and pregnanediol concentrations. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Urinary Lysosomal Enzyme Activities and Albuminuria in Ghanaian Patients with Type 2 Diabetes Mellitus

2016 ◽  
Vol 2016 ◽  
pp. 1-5 ◽  
Author(s):  
Henry Asare-Anane ◽  
Felix Twum ◽  
Emmanuel Kwaku Ofori ◽  
Erving L. Torgbor ◽  
Seth D. Amanquah ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Lysosomal Enzyme ◽  
Enzyme Activities ◽  
Renal Involvement ◽  
Fasting Blood Glucose ◽  
Urine Samples ◽  
Albumin Concentration ◽  
Spot Urine ◽  
Alanine Aminopeptidase

Renal tubular lysosomal enzyme activities like alanine aminopeptidase (AAP) and N-acetyl-β-D-glucosaminidase (NAG) have been shown to increase in patients developing diabetic nephropathy and nephrosclerosis. This study aimed to determine the activities of N-acetyl-β-D-glucosaminidase and alanine aminopeptidase and albumin concentration in urine samples of patients with type 2 diabetes. One hundred and thirty (65 type 2 diabetic and 65 nondiabetic) subjects participated in this study. Blood samples were drawn for measurements of fasting blood glucose, albumin (Alb), lipids, and creatinine (Cr). Early morning spot urine samples were also collected for activities of alanine aminopeptidase (AAP), N-acetyl-β-D-glucosaminidase (NAG), and concentration of albumin (U-Alb) and creatinine (U-Cr). Both NAG/Cr and AAP/Cr were significantly increased in diabetic subjects compared to controls (p<0.001). There was positive correlation between NAG/Cr and Alb/Cr (r=0.49,p<0.001) and between NAG/Cr and serum creatinine (r=0.441,p<0.001). A negative correlation was found between NAG/Cr and eGFR (r=-0.432,p<0.05). 9.3% and 12% of diabetics with normoalbuminuria had elevated levels of AAP/Cr and NAG/Cr, respectively. We conclude that measuring the urinary enzymes activities (NAG/Cr and AAP/Cr) could be useful as a biomarker of early renal involvement in diabetic complications.

scholarly journals A Convenient Colorimetric Bacteria Detection Method Utilizing Chitosan-Coated Magnetic Nanoparticles

Nanomaterials ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 92 ◽  
Author(s):  
Thao Nguyen Le ◽  
Tai Duc Tran ◽  
Moon Il Kim
Keyword(s):  
Magnetic Nanoparticles ◽  
Bacterial Infections ◽  
Colorimetric Assay ◽  
Point Of Care ◽  
Bacterial Cells ◽  
Diammonium Salt ◽  
Iron Oxide Magnetic Nanoparticles ◽  
Novel Strategy ◽  
Positively Charged ◽  
Timely Treatment

An effective novel strategy to detect bacteria is promising because it may improve human health by allowing early diagnosis and timely treatment of bacterial infections. Here, we report a simple, reliable, and economical colorimetric assay using the peroxidase-like activity of chitosan-coated iron oxide magnetic nanoparticles (CS-MNPs). When CS-MNPs are incubated with a sample containing bacterial cells such as the gram-negative Escherichia coli or the gram-positive Staphylococcus aureus, the negatively-charged bacterial membrane interacts with positively-charged chitosan on the surface of CS-MNPs, thus resulting in significant reduction of their peroxidase-like activity presumably by a hindrance in the accessibility of the negatively charged substrate, 2-2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) to the positively-charged CS-MNPs. This simple colorimetric strategy allowed the rapid detection of bacterial cells down to 104 CFU mL−1 by the naked eye and 102 CFU mL−1 by spectrophotometry within 10 min. Based on the results, we anticipate that the CS-MNPs-based assay has great potential for the on-site diagnosis of bacterial infections in facility-limited or point-of-care testing (POCT) environments.

Screening for microalbuminuria in patients with diabetes mellitus: frozen storage of urine samples decreases their albumin content.

1989 ◽  
Vol 35 (2) ◽  
pp. 308-310 ◽  
Author(s):  
L D Elving ◽  
J A Bakkeren ◽  
M J Jansen ◽  
C M de Kat Angelino ◽  
E de Nobel ◽  
...  
Keyword(s):  
Frozen Storage ◽  
Urine Samples ◽  
Diabetic Patients ◽  
Albumin Concentration ◽  
Low Concentrations ◽  
Albumin Content ◽  
Patients With Diabetes ◽  
The Difference ◽  
Urinary Albumin Concentration

Abstract The influence of storage on urinary albumin concentration was prospectively studied with use of overnight urine specimens (Albustix negative) from 73 diabetic patients. From each urine sample four aliquots were taken. One was stored at 4 degrees C and assayed within two weeks, the other three were stored at -20 degrees C and assayed within two weeks and after two and six months. Albumin concentration was measured with laser immunonephelometry. The detection limit, 1 mg/L, suffices for the screening of diabetic patients for microalbuminuria. After storage for two and six months at -20 degrees C, significantly lower albumin concentrations were found. The difference was mainly caused by lower concentrations found in urine samples in which a precipitate had formed, which was the case in 22 and 25 samples, respectively. Thus, freezing of urine samples for determination of low concentrations of albumin may yield falsely low results. Urine samples are best stored at 4 degrees C and assayed within two weeks.

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