Furthermore, significant correlations between these serum antioxidants (Thiol, CUPRAC, TEAC2) and acute phase proteins, such as haptoglobin (Hp) and serum amyloid A (SAA), have been observed in cats with pyometra, suggesting that acute phase proteins (APPs) may serve as prognostic biomarkers for pyometra in this species [94,105]. Here, HP is linked to pyometritis.