Chronic kidney disease (CKD) has become a major issue in long-term healthcare. It is caused by recurrent kidney injury, which is possible induced by dehydration and heat stress. Therefore, it is important to access the dehydration diagnosis on fields. Conventional instruments for assessing dehydration from blood and urine samples are expensive and time-consuming. These disadvantages limit their applications in high-risk groups susceptible to kidney disease. To address this unmet need, this study presents a portable miniaturized device for dehydration diagnosis with clinical saliva samples. With co-plane coating-free gold electrodes, the dehydration diagnosis was achieved with a saliva specimen at low volumes (50–500 μL). To examine the characteristics, the developed device was assessed by using standard conductivity solutions and the examined variation was <5%. To validate the use for field applications, saliva samples were measured by the developed device and the measured results were compared with standard markers of serum osmolality (N = 30). These data indicate that the measured saliva conductivity is consistent with serum osmolality. And it shows significant difference between healthy adults and healthy farmers (p < 0.05), who typically suffer high risks of CKD. Based on this work, the proposed device and measurement offer a useful method to diagnosis dehydrations and indicate possible potential for CKD.
The prevalence of chronic kidney disease (CKD) is increasing, and it brings an enormous healthcare burden. The traditional measurement of kidney function needs invasive blood tests, which hinders the early detection and causes low awareness of CKD. We recently designed a device with miniaturized coplanar biosensing probes for measuring salivary conductivity at an extremely low volume (50 μL). Our preliminary data discovered that the salivary conductivity was significantly higher in the CKD patients. This cross-sectional study aims to validate the relationship between salivary conductivity and kidney function, represented by the estimated glomerular filtration rate (eGFR). We enrolled 214 adult participants with a mean age of 63.96 ± 13.53 years, of whom 33.2% were male. The prevalence rate of CKD, defined as eGFR < 60 mL/min/1.73 m2, is 11.2% in our study. By multivariate linear regression analyses, we found that salivary conductivity was positively related to age and fasting glucose but negatively associated with eGFR. We further divided subjects into low, medium, and high groups according to the tertials of salivary conductivity levels. There was a significant trend for an increment of CKD patients from low to high salivary conductivity groups (4.2% vs. 12.5% vs. 16.9%, p for trend: 0.016). The receiver operating characteristic (ROC) curves disclosed an excellent performance by using salivary conductivity combined with age, gender, and body weight to diagnose CKD (AUC equal to 0.8). The adjusted odds ratio of CKD is 2.66 (95% CI, 1.10–6.46) in subjects with high salivary conductivity levels. Overall, salivary conductivity can serve as a good surrogate marker of kidney function; this real-time, non-invasive, and easy-to-use portable biosensing device may be a reliable tool for screening CKD.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.