Discordance between urine pH measured by dipstick and pH meter: Implications for methotrexate administration protocols

Wockenfus, Amy M.; Koch, Christopher D.; Conlon, Patricia M.; Sorensen, Linda D.; Cambern, Kari L; Chihak, Amy; Zmolek, Julie A.; Petersen, Amy E.; Burns, Bradley E.; Lieske, John C.; Karon, Brad S.

doi:10.1016/j.clinbiochem.2012.10.018

Cited by 8 publications

(6 citation statements)

References 5 publications

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“…The clinical cut-off for the urine pH should be pH 8.0, but after several experiments and sampling, the result using the dipstick was less than pH 8.0. However, when a pH meter was used, the result was greater than pH 8.0 [18].…”

Section: Ph Levelmentioning

confidence: 96%

Characterization of an ISFET with Built-in Calibration Registers through Segmented Eight-Bit Binary Search in Three-Point Algorithm Using FPGA

Manlises

Cruz

Chung

et al. 2017

JLPEA

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Sensors play the most important role in observing changes in an environment they are a part. They detect even the smallest changes and send the information to other electronic devices. Making sure that these sensors provide an accurate output is equally crucial, as the data it measures and collects are used for analysis. Until now, calibrating sensors has been done manually by following a sequence of procedures, and is usually performed on-site or in a laboratory prior to deployment. To eliminate the manual procedure in the calibration (at the very least), an ion-sensitive field-effect transistor (ISFET) with a built-in calibration registers circuit was created through segmented eight-bit binary search in a three-point algorithm using a field-programmable gate array (FPGA). The circuit was created using a three-point calibration algorithm and three standard buffers (pH 4, pH 7, and pH 10). The block diagram, schematic diagram, and the number of logic gates were derived after synthesizing the Verilog program in Xilinx/FPGA. An average of 0.30% error was computed to prove the reliability of the created circuit using FPGA. Having an ISFET with built-in calibration registers will alleviate the work of experts in performing calibrations. This would follow the plug and play standard, hence its being a calibration-ready ISFET device. With this feature, it could be used as a pH level meter or a remote sensor node in several applications.

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Section: Ph Levelmentioning

confidence: 96%

Characterization of an ISFET with Built-in Calibration Registers through Segmented Eight-Bit Binary Search in Three-Point Algorithm Using FPGA

Manlises

Cruz

Chung

et al. 2017

JLPEA

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“…In clinical practice, dipsticks are often used, which are much more available but less accurate, providing a value only up to the nearest 0.5 unit interval and being prone to perception bias when electronic readers are not used. Although dipsticks are useful in most situations, differences between dipstick and pH-meter readings can be as high as 0.4–0.5 units ( 19 – 21 ), even with electronic readers ( 22 , 23 ). These differences might be clinically significant and thus lead to wrong clinical decisions in specific contexts ( 22 ).…”

Section: Introduction: Physiology and Technical Aspectsmentioning

confidence: 99%

“…Although dipsticks are useful in most situations, differences between dipstick and pH-meter readings can be as high as 0.4–0.5 units ( 19 – 21 ), even with electronic readers ( 22 , 23 ). These differences might be clinically significant and thus lead to wrong clinical decisions in specific contexts ( 22 ).…”

Section: Introduction: Physiology and Technical Aspectsmentioning

confidence: 99%

Evaluation of urinary acidification in children: Clinical utility

Díaz-Anadón

Cardo²,

Santos³

et al. 2022

Front. Pediatr.

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The kidney plays a fundamental role in acid-base homeostasis by reabsorbing the filtered bicarbonate and by generating new bicarbonate, to replace that consumed in the buffering of non-volatile acids, a process that leads to the acidification of urine and the excretion of ammonium (NH4+). Therefore, urine pH (UpH) and urinary NH4+ (UNH4+) are valuable parameters to assess urinary acidification. The adaptation of automated plasma NH4+ quantification methods to measure UNH4+ has proven to be an accurate and feasible technique, with diverse potential indications in clinical practice. Recently, reference values for spot urine NH4+/creatinine ratio in children have been published. UpH and UNH4+, aside from their classical application in the study of metabolic acidosis, have shown to be useful in the identification of incomplete distal renal tubular acidosis (dRTA), an acidification disorder, without overt metabolic acidosis, extensively described in adults, and barely known in children, in whom it has been found to be associated to hypocitraturia, congenital kidney abnormalities and growth impairment. In addition, a low UNH4+ in chronic kidney disease (CKD) is a risk factor for glomerular filtration decay and mortality in adults, even in the absence of overt metabolic acidosis. We here emphasize on the need of measuring UpH and UNH4+ in pediatric population, establishing reference values, as well as exploring their application in metabolic acidosis, CKD and disorders associated with incomplete dRTA, including growth retardation of unknown cause.

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“…The advantages of automated urinalysis established in human medicine include decreased operator time, decreased turn‐around time (if the automated results are connected to the laboratory information management system or LIMS), increased precision (decreased intra‐ and interobserver error), elimination of transcription error to the LIMS, and the potential for improved accuracy . Increased accuracy is particularly important for some analytes, such as pH, which are known to suffer from poor diagnostic accuracy using dipstick urinalysis techniques …”

Section: Introductionmentioning

confidence: 99%

Optimizing the u411 automated urinalysis instrument for veterinary use

Sharp

Vap

2020

Veterinary Clinical Pathol

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Background The Cobas u411 Analyzer (Roche Diagnostics) is an automated, reflectance photometry‐based urinalysis instrument designed for use with Roche's CHEMSTRIP 10UA technology and human urine samples. Objective We aimed to optimize and validate the Cobas u411 Analyzer for use in canine and feline urinalysis. Methods Patient urine samples presenting to the Clinical Pathology Laboratory at the Colorado State University Veterinary Teaching Hospital were analyzed with the Cobas u411 and by manual readings in parallel. Initially, 223 canine and 83 feline urine samples were run using the u411 factory settings. Following comparisons with manual results, and evaluation for directional bias, adjustments to the reflectance values were made in the instrument's programming. An additional 183 canine and 95 feline samples were run using the adjusted settings. Total urine protein concentrations were measured in 48 samples and used to generate receiver operating characteristic curves for the protein test pad. Results Following adjustments in reflectance programming, concordance between u411 and manual results was increased by 17.7% for protein, 11.7% for ketones, and 4.5% for bilirubin. Concordances for pH, glucose, and blood were not substantially changed. Discordance for all analytes was ≤3%. Canine and feline samples had similar levels of discordance, though marginal concordance was higher in dogs for ketones, bilirubin, and blood. Conclusions Adjustments to the reflectance programming of the Cobas u411 Analyzer improved concordance with manual results for canine and feline samples. This instrument has the potential to greatly increase both efficiency and consistency of urinalysis procedures in higher throughput veterinary diagnostic laboratories.

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Discordance between urine pH measured by dipstick and pH meter: Implications for methotrexate administration protocols

Cited by 8 publications

References 5 publications

Characterization of an ISFET with Built-in Calibration Registers through Segmented Eight-Bit Binary Search in Three-Point Algorithm Using FPGA

Characterization of an ISFET with Built-in Calibration Registers through Segmented Eight-Bit Binary Search in Three-Point Algorithm Using FPGA

Evaluation of urinary acidification in children: Clinical utility

Optimizing the u411 automated urinalysis instrument for veterinary use

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