Do plasma protein:fibrinogen ratios in horses provide additional information compared with fibrinogen concentration alone?

The plasma protein:fibrinogen (PP:F) ratio was introduced to aid interpretation of hyperfibrinogenemia by accounting for dehydration. However, this ratio is inconsistently assessed in practice and its clinical value remains unknown. Our objective was to determine whether the PP:F ratio provides additional information in adult horses beyond fibrinogen concentration alone. Two databases were reviewed to identify 412 hyperfibrinogenemic horses. Plasma protein:fibrinogen ratios were calculated and their interpretation compared to the fibrinogen concentration. Ratios < 15 were supportive of inflammation. Albumin and total protein concentrations were evaluated when ratios were ≥ 15 to determine if inflammation was supported. Very good agreement (86%) was found on the presence of inflammation when PP:F ratios were compared to fibrinogen concentration. In 72% of cases in which PP:F ratios did not support inflammation, inflammation was considered likely based on albumin and total protein. These findings suggest that PP:F ratios do not provide additional information in horses over fibrinogen concentrations alone.