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C-reactive protein measurement in canine saliva
María Dolores Parra1, Fernando Tecles, Silvia Martínez-Subiela
1Department of Animal Medicine and Surgery, Faculty of Veterinary Medicine, University of Murcia, 30100 Murcia, Spain.
Insights
This study validates a canine C-reactive protein (CRP) assay for saliva, showing it accurately reflects blood CRP levels. Saliva CRP measurement offers a less stressful, more accessible diagnostic tool for canine health monitoring.
Area of Science:
- Veterinary diagnostics
- Biomarker analysis
- Immunochemistry
Background:
- C-reactive protein (CRP) is a key inflammatory biomarker in dogs.
- Current methods for CRP measurement often require blood collection, which can be stressful for animals.
- Developing non-invasive methods for CRP analysis is crucial for routine canine health monitoring.
Purpose of the Study:
- To evaluate and validate an established time-resolved immunofluorometric assay for measuring CRP in canine saliva.
- To assess the correlation between salivary CRP levels and serum CRP levels in dogs.
- To determine the utility of salivary CRP as a diagnostic marker for inflammatory conditions in dogs.
Main Methods:
- An existing canine blood CRP assay was adapted for canine saliva.
- CRP levels were measured in saliva from healthy dogs and dogs with various diseases.
- Analytical and functional limits of detection, as well as assay precision (intra- and interassay coefficients of variation), were determined.
- Recovery experiments and correlation analyses (saliva vs. serum) were performed.
Main Results:
- The assay demonstrated low limits of detection (analytical: 0.000053 µg/ml; functional: 0.0091 µg/ml) and acceptable precision (intra-assay CV: 6.7–9.9%; interassay CV: 8.5–16.5%).
- Saliva CRP measurements showed a strong positive correlation with serum CRP levels in both experimental (R² = 0.76) and clinical (R² = 0.70) studies.
- The assay successfully differentiated CRP levels between healthy dogs and those with inflammatory processes.
Conclusions:
- The validated assay is suitable for measuring CRP in canine saliva.
- Saliva CRP levels correlate well with serum CRP, indicating its potential as a reliable biomarker.
- Saliva-based CRP testing offers a less invasive and less stressful alternative for canine diagnostics, potentially enabling point-of-care or field use.
Abstract:
An established time-resolved immunofluorometric assay designed for measurement of C-reactive protein (CRP) in canine blood was evaluated and validated for use in canine saliva. C-reactive protein was measured in saliva specimens from 5 healthy dogs before and after the injection of casein and in 37 dogs with different disease conditions. The analytical and functional limits of detection were 0.000053 microg/ml and 0.0091 microg/ml, respectively, and intra- and interassay coefficients of variation ranged between 6.7-9.9% and 8.5-16.5%, respectively. A recovery experiment showed no significant disagreement between detected values and expected ones, and saliva CRP concentration was measured in a linear and proportional manner. A positive correlation was found between CRP levels obtained in saliva and serum samples in the experimental (R2 = 0.76) and clinical studies (R2 = 0.70). The assay was able to detect significant differences between salivary CRP levels in healthy dogs and dogs with inflammatory processes. These results suggest that saliva can be used for CRP measurement in dogs. The use of saliva presents the advantage of an easier and less stressful sampling method for the animals, which might be performed outside of hospital environments.
