Raskin Rose E, Murray Kelly A, Levy Julie K
Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA.
Vet Clin Pathol. 2002;31(2):51-5. doi: 10.1111/j.1939-165x.2002.tb00279.x.
Monitoring of urine pH, often done in the patient s home, is essential for proper clinical treatment and management of conditions such as urolithiasis.
The purpose of this study was to assess the agreement in pH readings between a standard laboratory method and methods readily available for home monitoring. The influence of refrigerated storage on urine pH was also examined.
Urine samples were obtained by cystocentesis from 40 clinically healthy cats, and pH was measured within 2 hours of collection. Each sample was evaluated using pH paper, urinalysis reagent strip, 2 brands of portable pH meters (Chek-Mite, Corning, Corning, NY, USA; and Checker 1, Hanna Instruments, Woonsocket, RI, USA), and a standard laboratory benchtop pH meter. Urine samples were refrigerated, and a second pH reading was obtained with the laboratory benchtop meter after 24 hours. The degree of agreement was assessed among the different methods, with the laboratory benchtop pH meter as the reference method.
The closest agreement was obtained with the Chek-Mite portable pH meter and least agreement with the Checker 1 portable pH meter, which had a constant negative bias of 0.31 units due to expiration of the electrode. As expected, pH paper and reagent strips had poor and intermediate agreement, respectively. The reagent strip method had a negative bias of 0.12 units when compared with the benchtop pH meter and wide disagreement at the low pH end. The reagent strip did not agree strongly with the reference method; only 50% of values were within 0.25 pH units of each other. The difference in pH between 0 hours (6.57 +/- 0.54) and 24 hours of refrigeration (6.61 +/- 0.53) was not considered clinically significant.
Portable pH meters are excellent for monitoring urine pH at home as long as attention is given to electrode maintenance. Urine can be collected at home and kept refrigerated, and pH may be measured reliably within 24 hours using the reference method or a portable pH meter.
尿pH监测通常在患者家中进行，对于诸如尿石症等病症的恰当临床治疗和管理至关重要。
本研究的目的是评估标准实验室方法与易于在家中监测的方法之间pH读数的一致性。还研究了冷藏储存对尿pH的影响。
通过膀胱穿刺术从40只临床健康的猫获取尿液样本，并在采集后2小时内测量pH。使用pH试纸、尿液分析试剂条、2个品牌的便携式pH计（美国纽约康宁公司的Chek-Mite；美国罗德岛伍索基特市哈纳仪器公司的Checker 1）和标准实验室台式pH计对每个样本进行评估。将尿液样本冷藏，24小时后使用实验室台式pH计再次读取pH值。以实验室台式pH计作为参考方法，评估不同方法之间的一致性程度。
Chek-Mite便携式pH计的一致性最接近，而Checker 1便携式pH计的一致性最差，由于电极过期，其存在0.31个单位的恒定负偏差。正如预期的那样，pH试纸和试剂条的一致性分别较差和中等。与台式pH计相比，试剂条法有0.12个单位的负偏差，并且在低pH端存在较大差异。试剂条与参考方法的一致性不强；只有50%的值在彼此0.25个pH单位范围内。0小时（6.57±0.54）和冷藏24小时（6.61±0.53）之间的pH差异在临床上不被认为具有显著性。
只要注意电极维护，便携式pH计非常适合在家中监测尿pH。尿液可以在家中收集并冷藏，使用参考方法或便携式pH计可在24小时内可靠地测量pH。
