Validation of two point-of-care tests against standard lab measures of NO in saliva and in serum.
Nitric oxide (NO) is an endogenous signaling molecule, which plays important roles in cardiometabolic health. A significant source of NO is dietary nitrate (NO3), which is initially metabolized by oral bacteria into nitrite (NO2-) and is subsequently converted into NO once digested in the acidic gastric environment. Inexpensive non-invasive tests for measuring nitrite from saliva have been developed as a means for individuals to monitor their NO bioavailability. However, few studies exist in the literature validating and comparing these products with standard lab assays. The objective of this study was to validate two commonly used commercial strips: Nitric Oxide Test Strips (Berkeley Test) and Nitric Oxide Indicator Strips (Neogenesis) against standard lab measures for saliva and serum nitrite/nitrate. A stratified random sample of 20 non-smoking, overweight or obese participants between 40 to 65 years of age, were selected for this study from the baseline data of the San Juan Overweight Adults Longitudinal Study (SOALS). There was a significant correlation between the measures from the two nitrite-detecting-strips after controlling for the stratification variables (metabolic syndrome, and mouthwash use) (r = 0.75). Measurements from both strips correlated significantly with salivary nitrite levels (r = 0.76 for Berkeley strips; r = 0.59 for Neogenesis). Neither of the strips had a significant correlation with the levels of saliva nitrate, serum nitrite and serum nitrate. In conclusion, commercially available Berkeley and Neogenesis strips provide a reasonable surrogate for salivary, but not for systemic nitrite levels.
Center for Clinical Research and Health Promotion, University of Puerto Rico, Medical Sciences Campus, San Juan, Puerto Rico, USA.
Ashwin
A
Modi
School of Dental Medicine, University of Puerto Rico, San Juan, Puerto Rico, USA.
Evangelia
E
Morou-Bermudez
Center for Clinical Research and Health Promotion, University of Puerto Rico, Medical Sciences Campus, San Juan, Puerto Rico, USA.
Jose
J
Vergara
Department of Pathology and Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
Rakesh P
RP
Patel
UAB School of Medicine, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
Alexandria
A
Nichols
Center for Clinical Research and Health Promotion, University of Puerto Rico, Medical Sciences Campus, San Juan, Puerto Rico, USA; Department of Epidemiology, Harvard T. H. Chan School of Public Health, Boston, USA. Electronic address: kaumudi.joshipura@upr.edu.
Kaumudi
K
Joshipura
D000328:Adult; D019963:Clinical Chemistry Tests / Q000379:methods / Q000592:standards*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000032:analysis* / Q000097:blood*; D000067716:Point-of-Care Testing / Q000592:standards*; D015203:Reproducibility of Results; D012463:Saliva / Q000737:chemistry*; D018709:Statistics, Nonparametric
D009569:Nitric Oxide