A Monte Carlo study of identified particle ratio fluctuations at LHC energies is carried out in the frame work of hij model using the fluctuation variable $ u_{dyn}$. The simulated events for Pb-Pb collisions at $sqrt{s}_{NN}$ = 2.76 and 5.02 TeV and Xe-Xe collisions at $sqrt{s}_{NN}$ = 5.44 TeV are analyzed. From this study, it is observed that the values of $[pi,K]$, $[p,K]$ and $[pi,p]$ follow the similar trends of energy dependence as observed in the most central collision data by NA49, STAR and ALICE experiments. It is also observed that $ u_{dyn}$ for all the three combinations of particles for semi-central and central collisions, the model predicted values of $ u_{dyn}[A,B]$ for Pb-Pb collisions at $sqrt{s}_{NN}$ = 2.76 TeV agree fairly well with those observed in ALICE experiment. For peripheral collisions, however, the model predicted values of $ u_{dyn}[pi,K]$ are somewhat smaller, whereas for $[p,K]$ and $[pi,p]$ it predicts larger values as compared to the corresponding experimental values. The possible reasons for the observed differences are discussed. The $ u_{dyn}$ values scaled with charged particle density when plotted against $langle$N$_{part}$$rangle$, exhibit a flat behaviour, as expected from the independent particle emission sources. For $[p,K]$ and $[pi,p]$ combinations, a departure from the flat trend is, however, observed in central collisions in the case of low p$_{T}$ window when effect of jet quenching or resonances are considered. Furthermore, the study of $ u_{dyn}[A,B]$ dependence on particle density for various collision systems (including proton-proton collisions) suggests that at LHC energies $ u_{dyn}$ values for a given particle pair is simply a function of charged particle density, irrespective of system size, beam energy and collision centrality.
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