Integrated line fluxes from TW Hya models (M_disk = 2.3 × 10^-2M_⊙, ψ = 0.3, h_c = 0.1, d = 59.54 pc, Astraatmadja & Bailer-Jones 2016) with different amounts of carbon/oxygen underabundances. The x-axis shows the various modelled transitions. The black bars show the observations for TW Hya (Schwarz et al. 2016; Kama et al. 2016b, and references therein). The purple crosses show the modelled line fluxes from the best fit model from Kama et al. (2016b; with δ_C = δ_O = 0.01). The coloured hexagons show the results from this work; the left-hand side shows the amount carbon underabundance (with respect to the ISM) and the right-hand side shows the amount of oxygen underabundance.