We identify the q-series associated to an 1-efficient ideal triangulation of a cusped hyperbolic 3-manifold by Frohman and Kania-Bartoszynska with the 3D-index of Dimofte– Gaiotto–Gukov. This implies the topological invariance of the q-series of Frohman and Kania- Bartoszynska for cusped hyperbolic 3-manifolds. Conversely, we identify the tetrahedron index of Dimofte–Gaiotto–Gukov as a limit of quantum 6j -symbols.