Two point threshold test, tests the integrity of:
Dorsal column (medial lemniscal system): Fibres mediating fine touch, fine pressure, two point discrimination, proprioception, joint position sense and vibration ascends in the dorsal column. Ref: Ganong's Review of medical physiology, 22 Edition, Page 138.
Anterior spinothalamic tract
Lateral coicospinal tract
Lateral spinothalamic tract
Dorsal column