Correlation of hepatic copper levels, rhodanine scores and histological diagnosis in archived canine liver samples.

The liver is the main storage site for copper. Excess copper accumulation, however, is a risk factor for the development of chronic hepatitis in dogs. Mass spectrometry or rhodanine staining are frequently used methods to assess copper levels in the liver. The association was studied between analytic hepatic copper levels and rhodanine scores in archived canine formalin-fixed-paraffinembedded liver sections from 2014 to 2021 with various diagnoses. Thirty-six (N = 36) liver samples with analytic interpretation of toxic (n = 12), high normal (n = 17), and normal (n = 7) copper levels were selected for the study. Rhodanine staining for each of these samples was graded (scale: 1 to 5), and the association was determined between actual liver copper levels and rhodanine scores and histological diagnoses (chronic hepatitis or other diagnoses). The analytic copper level and rhodanine scores were significantly higher (P < 0.05) in samples designated as toxic compared to normal. There was a significant association between hepatic copper levels and rhodanine scores (P < 0.05). Rhodanine score, but not the actual liver copper levels were significantly (P < 0.05) associated with chronic hepatitis versus other diagnoses. Rhodanine scores of ≥ 1.89 were statistically significant predictors of chronic hepatitis. It was concluded from this study that actual liver copper levels are positively associated with rhodanine scores and rhodanine scores can be a useful predictor of chronic hepatitis.