What Is the Best Method to Evaluate Urine pH? A Trial of Three Urinary pH Measurement Methods in a Stone Clinic

Ilyas, R.; Chow, Karyee; Young, J Graham

doi:10.1089/end.2014.0317

Cited by 15 publications

(12 citation statements)

References 12 publications

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“…1 , 2 , 3 , 4 ). However, the precision of our averaged pH dipstick reading is essentially the same as that found by Ilyas et al [ 10 ] when they compared 200 individual dipstick pH readings to laboratory pH meter. This indicates that we likely have reached the limits of precision achievable by dipstick pH monitoring, but dipsticks are not sufficiently precise to guide clinical management.…”

Section: Discussionsupporting

confidence: 79%

“…Kwong et al [ 4 ] tested 390 urine samples with both urinary dipstick and electrochemical pH meter and concluded that dipsticks had an unacceptable frequency of clinically relevant error. Similarly, Ilyas et al [ 10 ] compared a clinic-based portable pH meter, urinary dipsticks, and litmus paper to laboratory-based pH meter and found that dipsticks lacked the precision needed to base a clinical decision. However, to our knowledge, our study is the first to look beyond single dipstick pH readings in an attempt to account for diurnal variation in urinary pH.…”

Section: Discussionmentioning

confidence: 99%

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Optimization of urinary dipstick pH: Are multiple dipstick pH readings reliably comparable to commercial 24-hour urinary pH?

et al. 2017

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PurposeAccurate measurement of pH is necessary to guide medical management of nephrolithiasis. Urinary dipsticks offer a convenient method to measure pH, but prior studies have only assessed the accuracy of a single, spot dipstick. Given the known diurnal variation in pH, a single dipstick pH is unlikely to reflect the average daily urinary pH. Our goal was to determine whether multiple dipstick pH readings would be reliably comparable to pH from a 24-hour urine analysis.Materials and MethodsKidney stone patients undergoing a 24-hour urine collection were enrolled and took images of dipsticks from their first 3 voids concurrently with the 24-hour collection. Images were sent to and read by a study investigator. The individual and mean pH from the dipsticks were compared to the 24-hour urine pH and considered to be accurate if the dipstick readings were within 0.5 of the 24-hour urine pH. The Bland-Altman test of agreement was used to further compare dipstick pH relative to 24-hour urine pH.ResultsFifty-nine percent of patients had mean urinary pH values within 0.5 pH units of their 24-hour urine pH. Bland-Altman analysis showed a mean difference between dipstick pH and 24-hour urine pH of -0.22, with an upper limit of agreement of 1.02 (95% confidence interval [CI], 0.45–1.59) and a lower limit of agreement of -1.47 (95% CI, -2.04 to -0.90).ConclusionsWe concluded that urinary dipstick based pH measurement lacks the precision required to guide medical management of nephrolithiasis and physicians should use 24-hour urine analysis to base their metabolic therapy.

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Section: Discussionsupporting

confidence: 79%

Section: Discussionmentioning

confidence: 99%

Optimization of urinary dipstick pH: Are multiple dipstick pH readings reliably comparable to commercial 24-hour urinary pH?

et al. 2017

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“…Also, some dipsticks in our study were of unacceptable repeatability for pH. Some previous literature reports have also demonstrated unacceptable precision and accuracy of the dipsticks comparing them with gold standard, pH – meter ( 26 ). It has also been reported that dipsticks vary in accuracy due to proportions and combinations of the reagents (like methyl red and bromthymol blue) in pH fields provided by different manufacturers ( 27 ).…”

Section: Discussioncontrasting

confidence: 53%

Analytical verification of 12 most commonly used urine dipsticks in Croatia: comparability, repeatability and accuracy

Vuljanić¹,

Dojder²,

Špoljarić³

et al. 2018

Biochem. med. (Online)

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IntroductionVariability among manufacturers of urine dipsticks, respective to their accuracy and measurement range, may lead to diagnostic errors and thus create a serious risk for the patient. Our aims were to determine the level of agreement between 12 most commonly used urine dipsticks in Croatia, examine their accuracy for glucose and total protein and to test their repeatability.Materials and methodsA total of 75 urine samples were used to examine comparability and accuracy of 12 dipstick brands (Combur 10 TestM, ChoiceLine 10, Combur 10 TestUX, ComboStik 10M, ComboStik 11M, CombiScreen 11SYS, CombiScreen 10SL, Combina 13, Combina 11S, Combina 10M, UriGnost 11, Multistix 10SG). Agreement between each dipstick and the reference (Combur 10 TestM) was expressed as kappa coefficient (acceptable κ ≥ 0.80). Accuracy for glucose and total protein was tested by comparison with quantitative measurements on analysers: AU400 (Beckman Coulter, USA), Cobas 6000 c501 (Roche Diagnostics, Germany) and Architect plus c4000 (Abbott, USA). Repeatability was assessed on 20 replicates (acceptable > 90%).ResultsBest agreement was achieved for glucose, total protein and nitrite (11/11, k > 0.80) and the lowest for bilirubin (5/5, k < 0.60). Sensitivities for total protein were 41-75% (AU400) and 56-92% (Cobas and Architect); while specificities were 41-75% (AU400, Cobas, Architect). Dipsticks’ sensitivity and specificity for glucose were 68-98%. Most of the dipsticks showed unacceptable repeatability (6/12, < 90%) for one parameter, most prominently for pH (3/12, < 90%).ConclusionsMost commonly used dipsticks in Croatia showed low level of agreement between each other. Moreover, their repeatability varies among manufacturers and their accuracy for glucose and proteins is poor.

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“…20) In the studies comparing accuracy and reproducibility between benchtop pH meter and portable pH meters, portable pH meters had nearly perfect agreement with the benchtop pH meter. 20,21) In the current study, the salivary pH measurements using pH paper showed adequate agreement with those using pH meter. However, pH paper exhibited lower pH values compared to those by pH meter (paired t-test, p<0.001; Table 3).…”

Section: Discussionsupporting

confidence: 64%

Clinical Usefulness of pH Papers in the Measurement of Salivary pH

Song¹,

Kim²,

Kim³

2015

Journal of Oral Medicine and Pain

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Purpose: Salivary pH is an easily measurable biochemical marker and related to various intraoral and systemic conditions. The aim of this study was to evaluate the reliability of the salivary pH measurement using pH paper. In addition, the normal values of salivary pH using pH paper were compared to those of pH meter to investigate the validity.Methods: Twenty healthy male participants attended this study (mean age, 24.5±1.47 years). Unstimulated saliva and stimulated saliva were collected from each subject two times with the interval of a day and salivary pH was immediately measured by the two experienced examiners using pH paper and pH meter. The salivary pH was compared between the groups and inter-and intra-examiner reliability of pH paper was investigated. The intraclass correlation coefficient (ICC) was used to calculate variations. Results:All measurements had good to excellent inter-examiner (ICC 0.755 for unstimulated; 0.760 for stimulated saliva), intra-examiner (ICC 0.635 for unstimulated; 0.592 for stimulated saliva) reliability and two measurement methods using pH paper and pH paper also showed high reliability (ICC 0.852 for unstimulated; 0.640 for stimulated saliva). The values measured by pH paper were significantly lower than those measured by pH meter.Conclusions: pH paper showed adequate inter-and intra-examiner reliability and it presented the validity in terms of comparison with the pH meter as a standard in the salivary pH measurement.

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What Is the Best Method to Evaluate Urine pH? A Trial of Three Urinary pH Measurement Methods in a Stone Clinic

Abstract: The hand-held pH device gave urinary pH readings that most closely and consistently matched those of the reference bench-top laboratory machine. This method of pH measurement should be considered in stone clinics in patients with pH-dependent stone risk.

Cited by 15 publications

References 12 publications

Optimization of urinary dipstick pH: Are multiple dipstick pH readings reliably comparable to commercial 24-hour urinary pH?

Optimization of urinary dipstick pH: Are multiple dipstick pH readings reliably comparable to commercial 24-hour urinary pH?

Analytical verification of 12 most commonly used urine dipsticks in Croatia: comparability, repeatability and accuracy

Clinical Usefulness of pH Papers in the Measurement of Salivary pH

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