BALF C-reactive protein shows promise, limits in canine pneumonia

Dogs with suspected bacterial bronchopneumonia may eventually have another data point to work with during bronchoalveolar lavage, but early evidence suggests bronchoalveolar lavage fluid C-reactive protein, or BALF-CRP, is better at ruling in disease than ruling it out. In a multicenter prospective study presented at the 2024 ECVIM-CA Congress, investigators evaluated 80 BALF samples collected from dogs between 2022 and 2024 and found that BALF-CRP above 5 mg/L had 30% sensitivity and 80% specificity for bacterial bronchopneumonia; at a cutoff above 11 mg/L, specificity rose to 94%, while sensitivity dropped to 20%. When BALF-CRP above 11 mg/L was paired with plasma CRP of at least 50 mg/L, specificity reached 100%, though sensitivity remained low at 18%. (academic.oup.com)

Why it matters: Diagnosis of canine bacterial bronchopneumonia still leans heavily on BALF cytology and bacterial culture, both of which have practical limitations, including turnaround time, contamination risk, and imperfect correlation with antimicrobial need. Prior canine studies have shown serum CRP can help distinguish bacterial pneumonia from other respiratory diseases, with bacterial pneumonia cases showing markedly higher serum CRP concentrations than dogs with nonbacterial respiratory conditions. This new BALF-focused work suggests local CRP measurement could become a useful adjunct when positive, especially while clinicians are waiting for cytology and culture, but its low sensitivity means it can't replace current diagnostics or justify withholding treatment when suspicion is high. (pubmed.ncbi.nlm.nih.gov)

What to watch: Watch for the full peer-reviewed Journal of Veterinary Diagnostic Investigation paper, which should clarify assay performance, case definitions, and whether BALF-CRP can be integrated into antimicrobial decision-making algorithms. (academic.oup.com)