Comparison of capillary zone and agarose gel protein electrophoresis in macaws (Ara spp.)

The avian inflammatory response is complex and requires integration of clinical examination findings alongside hematologic, biochemical, and protein electrophoretic data to best characterize the acute phase and immune response. Interpretation of protein electrophoresis in birds, however, is challenging due to methodological variability, inconsistent fraction resolution, and the lack of established species- and method-specific reference intervals. Psittacine birds represent the largest family of companion avian patients in clinical practice, emphasizing the need for reliable and clinically applicable data for diagnostic interpretation. This study compared agarose gel electrophoresis (AGE) and capillary zone electrophoresis (CZE) in 42 client-owned macaws (Ara spp.) complemented by paired serum-plasma analysis. Birds were classified as clinically normal or abnormal based on examination findings and clinicopathologic data. Capillary zone electrophoresis resolved seven protein fractions compared to six fractions resolved by AGE. Method comparison statistics demonstrated weak to moderate correlation, but poor agreement by Bland-Altman analysis, with systematic bias across all fractions, confirming results between methods are not equivalent. In an exploratory investigation, the abnormal group was found to demonstrate significantly increased total leukocyte and heterophil counts, with negative correlations between these parameters and the albumin-to-globulin ratio. Notable electrophoretic alterations were observed in select diseased birds. Agarose gel electrophoresis and CZE yielded analytically different results in the samples. These findings support the need for method-specific reference intervals and emphasize the importance of integrating protein electrophoresis results with clinical and hematologic findings.