CD68 and myelofibrosis: Using a cut-off of 1.63, the CD68/CD163 ratio yielded a sensitivity of 66.7% and specificity of 63.3% for thrombosis prediction (AUC = 0.677), and for secondary myelofibrosis, a cut-off of 1.55 gave a sensitivity of 80.9% and specificity of 75% (AUC = 0.779).