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Table 1 Relative bias of model parameters using non linear mixed models taking into account left-censored (undetectable) values (corrected) or not (crude) with simulated data. N = 20 patients, 1000 simulations, 14% left-censored measures in average.

From: Estimation of dynamical model parameters taking into account undetectable marker values

Parameter and true value Crude estimate Corrected estimate
   Estimates Relative bias (%) Estimates Relative bias (%)
Fixed effects
V 0 6.16 log10 IU/mL 6.09 -1.1 6.16 -0.021
δ 0.40 day-1 0.18 -55.2 0.40 +0.78
c 2.00 day-1 1.10 -44.8 2.03 +1.5
ε 0.80 0.93 +15.8 0.79 -1.3
Variances
σ γ 0 2 MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacH8akY=wiFfYdH8Gipec8Eeeu0xXdbba9frFj0=OqFfea0dXdd9vqai=hGuQ8kuc9pgc9s8qqaq=dirpe0xb9q8qiLsFr0=vr0=vr0dc8meaabaqaciaacaGaaeqabaqabeGadaaakeaaiiGacqWFdpWCdaqhaaWcbaGae83SdC2aaSbaaWqaaiabicdaWaqabaaaleaacqaIYaGmaaaaaa@325D@ 0.49 0.59 +20.3 0.46 -6.4
σ γ 1 2 MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacH8akY=wiFfYdH8Gipec8Eeeu0xXdbba9frFj0=OqFfea0dXdd9vqai=hGuQ8kuc9pgc9s8qqaq=dirpe0xb9q8qiLsFr0=vr0=vr0dc8meaabaqaciaacaGaaeqabaqabeGadaaakeaaiiGacqWFdpWCdaqhaaWcbaGae83SdC2aaSbaaWqaaiabigdaXaqabaaaleaacqaIYaGmaaaaaa@325F@ 2.69 2.18 -18.8 2.31 -13.9
σ e 2 MathType@MTEF@5@5@+=feaafiart1ev1aaatCvAUfKttLearuWrP9MDH5MBPbIqV92AaeXatLxBI9gBaebbnrfifHhDYfgasaacH8akY=wiFfYdH8Gipec8Eeeu0xXdbba9frFj0=OqFfea0dXdd9vqai=hGuQ8kuc9pgc9s8qqaq=dirpe0xb9q8qiLsFr0=vr0=vr0dc8meaabaqaciaacaGaaeqabaqabeGadaaakeaaiiGacqWFdpWCdaqhaaWcbaGaemyzaugabaGaeGOmaidaaaaa@30E8@ 0.04 0.09 +133.2 0.039 -2.4