Fig. 5
Analysis of serum TK1 levels. A. Comparison of serum TK1 levels in the control group without concurrent disease (Controls, n = 40), the lymphoma (n = 7) and suspected lymphoma (n = 5) groups and the tumour-free group with concurrent diseases (nonneoplastic diseases, n = 107). Bars represent the median. Receiver operating characteristic (ROC) analysis of serum TK1 activity to distinguish horses with lymphoma B and nonneoplastic diseases (nontumour diseases) C from the control group without concurrent diseases. The sensitivity and specificity were determined based on the chosen cut-off of 0.65 pmol/min/ml. To distinguish lymphoma from nonneoplastic diseases (nontumour disease group) D, the sensitivity and specificity were determined at a chosen cut-off value of 1.0 pmol/min/ml (mean + 2 SD)