The following page describes all the parameters computed by the non compartmental analysis. Parameter names are fixed and cannot be changed.
 Parameters related to \(\lambda_z\)
 Parameters related to plasma/blood measurements
 Parameters related to plasma/blood measurements specific to steady state dosing regimen
 Parameters related to urine measurements
 Parameters related to sparse NCA
 Parameter renamings
 Custom (userdefined) NCA parameters
Parameters related to \(\lambda_z\)
Name  PKPARMCD CDISC  PKPARM CDISC  UNITS  DESCRIPTION 

Rsq  R2  R Squared  no unit  Goodness of fit statistic for the terminal (loglinear) phase between the linear regression and the data 
Rsq_adjusted  R2ADJ  R Squared Adjusted  no unit  Goodness of fit statistic for the terminal elimination phase, adjusted for the number of points used in the estimation of \(\lambda_z\) 
Corr_XY  CORRXY  Correlation Between TimeX and Log ConcY  no unit  Correlation between time (X) and log concentration (Y) for the points used in the estimation of \(\lambda_z\) 
No_points_lambda_z  LAMZNPT  Number of Points for Lambda z  no unit  Number of points considered in the \(\lambda_z\) regression 
Lambda_z  LAMZ  Lambda z  1/time  First order rate constant associated with the terminal (loglinear) portion of the curve. Estimated by linear regression of time vs. log concentration 
Lambda_z_lower  LAMZLL  Lambda z Lower Limit  time  Lower limit on time for values to be included in the \(\lambda_z\) calculation 
Lambda_z_upper  LAMZUL  Lambda z Upper Limit  time  Upperlimit on time for values to be included in the \(\lambda_z\) calculation 
HL_Lambda_z  LAMZHL  HalfLife Lambda z  time  Terminal halflife = ln(2)/Lambda_z 
Lambda_z_intercept  –  –  no unit  Intercept found during the regression for (\lambda_z\), i.e. value of the regression (in logscale) at time 0, i.e. the regression writes log(Concentration) = Lambda_z*t+Lambda_z_intercept 
Span  –  –  no unit  Ratio between the sampling interval of the measurements used for the \(\lambda_z\) and the terminal halflife = (Lambda_z_upper – Lambda_z_lower)*Lambda_z/ln(2) 
Parameters related to plasma/blood measurements
Name  PKPARMCD CDISC  PKPARM CDISC  UNITS  DESCRIPTION 

Tlag  TLAG  Time Until First Nonzero Conc  time  Tlag is the time prior to the first measurable (nonzero) concentration. Tlag is 0 if the first observation after the last dose is not 0 or LOQ. The value is set to 0 for non extravascular input. 
T0  time  Time of the dose  
Dose  amount  Amount of the dose  
N_Samples  –  –  no unit  Number of samples in the individuals. 
C0  C0  Initial Conc  amount/volume  If a PK profile does not contain an observation at dose time (C0), the following value is added Extravascular and Infusion data. For single dose data, a concentration of zero. For steadystate, the minimum observed during the dose interval. IV Bolus data. Loglinear regression of first two data points to backextrapolate C0. 
Tmax  TMAX  Time of CMAX  time  Time of maximum observed concentration. – For nonsteadystate data, the entire curve is considered. – For steadystate data, Tmax corresponds to points collected during a dosing interval. If the maximum observed concentration is not unique, then the first maximum is used. 
Cmax  CMAX  Max Conc  amount/volume  Maximum observed concentration, occurring at Tmax. If not unique, then the first maximum is used. 
Cmax_D  CMAXD  Max Conc Norm by Dose  1/volume  Maximum observed concentration divided by dose. Cmax_D = Cmax/Dose 
Tlast  TLST  Time of Last Nonzero Conc  time  Last time point with measurable concentration 
Clast  CLST  Last Nonzero Conc  amount/volume  Concentration of last time point with measurable concentration 
AUClast  AUCLST  AUC to Last Nonzero Conc  time.amount/volume  Area under the curve from the time of dosing to the last measurable positive concentration. The calculation depends on the Integral method setting. 
AUClast_D  AUCLSTD  AUC to Last Nonzero Conc Norm by Dose  time/volume  Area under the curve from the time of dosing to the last measurable concentration divided by the dose. AUClast_D = AUClast/Dose 
AUMClast  AUMCLST  AUMC to Last Nonzero Conc  time2.amount/volume  Area under the moment curve (area under a plot of the product of concentration and time versus time) from the time of dosing to the last measurable concentration. 
MRTlast  MRTIVLST  MRT Intravasc to Last Nonzero Conc  time  [if intravascular] Mean residence time from the time of dosing to the time of the last measurable concentration, for a substance administered by intravascular dosing. MRTlast_iv = AUMClast/AUClast – TI/2, where TI represents infusion duration. 
MRTlast  MRTEVLST  MRT Extravasc to Last Nonzero Conc  time  [if extravascular] Mean residence time from the time of dosing to the time of the last measurable concentration for a substance administered by extravascular dosing. MRTlast_ev = AUMClast/AUClast – TI/2, where TI represents infusion duration. 
AUCall  AUCALL  AUC All  time.amount/volume  Area under the curve from the time of dosing to the time of the last observation. If the last concentration is positive AUClast=AUCall. Otherwise, AUCall will not be equal to AUClast as it includes the additional area from the last measurable concentration down to zero or negative observations. 
AUCINF_obs  AUCIFO  AUC Infinity Obs  time.amount/volume  AUC from Dosing_time extrapolated to infinity, based on the last observed concentration. AUCINF_obs = AUClast + Clast/Lambda_z 
AUCINF_D_obs  AUCIFOD  AUC Infinity Obs Norm by Dose  time/volume  AUCINF_obs divided by dose AUCINF_D_obs = AUCINF_obs/Dose 
AUC_PerCentExtrap_obs  AUCPEO  AUC %Extrapolation Obs  %  Percentage of AUCINF_obs due to extrapolation from Tlast to infinity. AUC_%Extrap_obs = 100*(1 AUClast / AUCINF_obs) 
AUC_PerCentBack_Ext_obs  AUCPBEO  AUC %Back Extrapolation Obs  %  Applies only for intravascular bolus dosing. the percentage of AUCINF_obs that was due to back extrapolation to estimate C(0). 
AUMCINF_obs  AUMCIFO  AUMC Infinity Obs  time2.amount/volume  Area under the first moment curve to infinity using observed Clast AUMCINF_obs = AUMClast + (Clast/Lambda_z)*(Tlast + 1.0/Lambda_z) 
AUMC_PerCentExtrap_obs  AUMCPEO  AUMC % Extrapolation Obs  %  Extrapolated (% or total) area under the first moment curve to infinity using observed Clast AUMC_%Extrap_obs = 100*(1 AUMClast / AUMCINF_obs) 
MRTINF_obs  MRTIVIFO  MRT Intravasc Infinity Obs  time  [if intravascular] Mean Residence Time extrapolated to infinity for a substance administered by intravascular dosing using observed Clast MRTINF_obs_iv = AUMCINF_obs/AUCINF_obs TI/2, where TI represents infusion duration. 
MRTINF_obs  MRTEVIFO  MRT Extravasc Infinity Obs  time  [if extravascular] Mean Residence Time extrapolated to infinity for a substance administered by extravascular dosing using observed Clast MRTINF_obs_ev = AUMCINF_obs/AUCINF_obs 
Vz_F_obs  VZFO  Vz Obs by F  volume  [if extravascular] Volume of distribution associated with the terminal phase divided by F (bioavailability) Vz_F_obs = Dose/Lambda_z/AUCINF_obs 
Cl_F_obs  CLFO  Total CL Obs by F  volume/time  [if extravascular] Clearance over F (based on observed Clast) Cl_F_obs = Dose/AUCINF_obs 
Vz_obs  VZO  Vz Obs  volume  [if intravascular] Volume of distribution associated with the terminal phase Vz_obs= Dose/Lambda_z/AUCINF_obs 
Cl_obs  CLO  Total CL Obs  volume/time  [if intravascular] Clearance (based on observed Clast) Cl_obs = Dose/AUCINF_obs 
Vss_obs  VSSO  Vol Dist Steady State Obs  volume  [if intravascular] An estimate of the volume of distribution at steady state based last observed concentration. Vss_obs = MRTINF_obs*Cl_obs 
Clast_pred  –  –  amount/volume  Clast_pred = exp(Lambda_z_intercept Lambda_z* Tlast) The values alpha (corresponding to the yintercept obtained when calculating \(\lambda_z\)) and lambda_z are those values found during the regression for \(\lambda_z\) 
AUCINF_pred  AUCIFP  AUC Infinity Pred  time.amount/volume  Area under the curve from the dose time extrapolated to infinity, based on the last predicted concentration, i.e., concentration at the final observation time estimated using the linear regression performed to estimate \(\lambda_z\) . AUCINF_pred = AUClast + Clast_pred/Lambda_z 
AUCINF_D_pred  AUCIFPD  AUC Infinity Pred Norm by Dose  time/volume  AUCINF_pred divided by dose = AUCINF_pred/Dose 
AUC_PerCentExtrap_pred  AUCPEP  AUC %Extrapolation Pred  %  Percentage of AUCINF_pred due to extrapolation from Tlast to infinity AUC_%Extrap_pred = 100*(1 AUClast / AUCINF_pred) 
AUC_PerCentBack_Ext_pred  AUCPBEP  AUC %Back Extrapolation Pred  %  Applies only for intravascular bolus dosing. The percentage of AUCINF_pred that was due to back extrapolation to estimate C(0). 
AUMCINF_pred  AUMCIFP  AUMC Infinity Pred  time2.amount/volume  Area under the first moment curve to infinity using predicted Clast AUMCINF_pred = AUMClast + (Clast_pred/Lambda_z)*(Tlast+1/Lambda_z) 
AUMC_PerCentExtrap_pred  AUMCPEP  AUMC % Extrapolation Pred  %  Extrapolated (% or total) area under the first moment curve to infinity using predicted Clast AUMC_%Extrap_pred = 100*(1 AUMClast / AUMCINF_pred) 
MRTINF_pred  MRTIVIFP  MRT Intravasc Infinity Pred  time  [if intravascular] Mean Residence Time extrapolated to infinity for a substance administered by intravascular dosing using predicted Clast 
MRTINF_pred  MRTEVIFP  MRT Extravasc Infinity Pred  time  [if extravascular] Mean Residence Time extrapolated to infinity for a substance administered by extravascular dosing using predicted Clast 
Vz_F_pred  VZFP  Vz Pred by F  volume  [if extravascular] Volume of distribution associated with the terminal phase divided by F (bioavailability) = Dose/Lambda_z/AUCINF_pred 
Cl_F_pred  CLFP  Total CL Pred by F  volume/time  [if extravascular] Clearance over F (using predicted Clast) Cl_F_pred = Dose/AUCINF_pred 
Vz_pred  VZP  Vz Pred  volume  [if intravascular] Volume of distribution associated with the terminal phas Vz_pred = Dose/Lambda_z/AUCINF_pred 
Cl_pred  CLP  Total CL Pred  volume/time  [if intravascular] Clearance (using predicted Clast) = Dose/AUCINF_pred 
Vss_pred  VSSP  Vol Dist Steady State Pred  volume  [if intravascular] An estimate of the volume of distribution at steady state based on the last predicted concentration. Vss_pred = MRTINF_pred*Cl_pred 
AUC_lower_upper  AUCINT  AUC from T1 to T2  time.amount/volume  AUC from T1 to T2 (partial AUC) 
AUC_lower_upper_D  AUCINTD  AUC from T1 to T2 Norm by Dose  time/volume  AUC from T1 to T2 (partial AUC) divided by Dose 
CAVG_lower_upper  CAVGINT  Average Conc from T1 to T2  amount/volume  Average concentration from T1 to T2 
Parameters related to plasma/blood measurements specific to steady state dosing regimen
In the case of repeated doses, dedicated parameters are used to define the steady state parameters and some specific formula should be considered for the clearance and the volume for example. Notice that all the calculation dedicated to the area under the first moment curve (AUMC) are not relevant.
Name  PKPARMCD CDISC  PKPARM CDISC  UNITS  DESCRIPTION 

Tau  –  time  The (assumed equal) dosing interval for steadystate data.  
Ctau  CTAU  Conc Trough  amount/volume  Concentration at end of dosing interval. If the observed concentration does not exist, the value is interpolated. It it cannot be interpolated, it is extrapolated using lambda_z. If lambda_z has not been computed, it is extrapolated as the last observed value. 
Ctrough  CTROUGH  Conc Trough  amount/volume  Concentration at end of dosing interval. If the observed concentration does not exist, the value is NaN. 
AUC_TAU  AUCTAU  AUC Over Dosing Interval  time.amount/volume  The area under the curve (AUC) for the defined interval between doses (TAU). The calculation depends on the Integral method setting. 
AUC_TAU_D  AUCTAUD  AUC Over Dosing Interval Norm by Dose  time/volume  The area under the curve (AUC) for the defined interval between doses (TAU) divided by the dose. AUC_TAU_D = AUC_TAU/Dose 
AUC_TAU_PerCentExtrap  –  –  % 
Percentage of AUC due to extrapolation in steady state.
AUC_TAU_%Extrap = 100*(AUC [Tlast, tau] if Tlast<=tau)/AUC_TAU;

AUMC_TAU  AUMCTAU  AUMC Over Dosing Interval  time2.amount/volume  The area under the first moment curve (AUMC) for the defined interval between doses (TAU). 
Vz_F  VZFTAU  Vz for Dose Int by F  volume  [if extravascular] The volume of distribution associated with the terminal slope following extravascular administration divided by the fraction of dose absorbed, calculated using AUC_TAU. Vz_F = Dose/Lambda_z/AUC_TAU 
Vz  VZTAU  Vz for Dose Int  volume  [if intravascular] The volume of distribution associated with the terminal slope following intravascular administration, calculated using AUC_TAU. Vz = Dose/Lambda_z/AUC_TAU 
CLss_F  CLFTAU  Total CL by F for Dose Int  volume/time  [if extravascular] The total body clearance for extravascular administration divided by the fraction of dose absorbed, calculated using AUC_TAU . CLss_F = Dose/AUC_TAU 
CLss  CLTAU  Total CL for Dose Int  volume/time  [if intravascular] The total body clearance for intravascular administration, calculated using AUC_TAU. CLss = Dose/AUC_TAU 
Cavg  CAVG  Average Concentration  amount/volume  AUCTAU divided by Tau. Cavg = AUC_TAU /Tau 
FluctuationPerCent  FLUCP  Fluctuation%  %  The difference between Cmin and Cmax standardized to Cavg, between dose time and Tau. Fluctuation% = 100.0* (Cmax Cmin)/Cavg 
FluctuationPerCent_Tau  –  –  %  The difference between Ctau and Cmax standardized to Cavg, between dose time and Tau. Fluctuation% _Tau = 100.0* (Cmax Ctau)/Cavg 
Accumulation_Index  AILAMZ  Accumulation Index using Lambda z  no unit  Theoretical accumulation ratio: Predicted accumulation ratio for area under the curve (AUC) calculated using the Lambda z estimated from single dose data. Accumulation_Index = 1.0/(1.0 exp(Lambda_z*Tau)) 
Swing  –  –  no unit  The degree of fluctuation over one dosing interval at steady state Swing = (Cmax Cmin)/Cmin 
Swing_Tau  –  –  no unit  Swing_Tau = (Cmax Ctau)/Ctau 
Tmin  TMIN  Time of CMIN observation.  time  Time of minimum concentration sampled during a dosing interval. 
Cmin  CMIN  Min Conc  amount/volume  Minimum observed concentration between dose time and dose time + Tau. 
Cmax  CMAX  Max Conc  amount/volume  Maximum observed concentration between dose time and dose time + Tau. 
MRTINF_obs  MRTIVIFO or MRTEVIFO  MRT Intravasc Infinity Obs or MRT Extravasc Infinity Obs  time  Mean Residence Time extrapolated to infinity using predicted Clast, calculated using AUC_TAU. 
Parameters related to urine measurements
Name  PKPARMCD CDISC  PKPARM CDISC  UNITS  DESCRIPTION 

T0  time  Time of the last administered dose (assumed to be zero unless otherwise specified). 

Dose  –  –  amount  Amount of the dose 
N_Samples  –  –  no unit  Number of samples in the individuals. 
Tlag  TLAG  Time Until First Nonzero Conc  time  Midpoint prior to the first measurable (nonzero) rate. 
Tmax_Rate  ERTMAX  Midpoint of Interval of Maximum ER  time  Midpoint of collection interval associated with the maximum observed excretion rate. 
Max_Rate  ERMAX  Max Excretion Rate  amount/time  Maximum observed excretion rate. 
Mid_Pt_last  ERTLST  Midpoint of Interval of Last Nonzero ER  time  Midpoint of collection interval associated with Rate_last. 
Rate_last  ERLST  Last Meas Excretion Rate  amount/time  Last measurable (positive) rate. 
AURC_last  AURCLST  AURC to Last Nonzero Rate  amount  Area under the urinary excretion rate curve from time 0 to the last measurable rate. 
AURC_last_D  AURCLSTD  AURC to Last Nonzero Rate Norm by Dose  no unit  The area under the urinary excretion rate curve (AURC) from time zero to the last measurable rate, divided by the dose. 
Vol_UR  VOLPK  Sum of Urine Vol  volume  Sum of Urine Volumes 
Amount_Recovered  amount  Cumulative amount eliminated.  
Percent_Recovered  %  100*Amount_Recovered/Dose  
AURC_all  AURCALL  AURC All  amount  Area under the urinary excretion rate curve from time 0 to the last rate. This equals AURC_last if the last rate is measurable. 
AURC_INF_obs  AURCIFO  AURC Infinity Obs  amount  Area under the urinary excretion rate curve extrapolated to infinity, based on the last observed excretion rate. 
AURC_PerCentExtrap_obs  AURCPEO  AURC % Extrapolation Obs  %  Percent of AURC_INF_obs that is extrapolated 
AURC_INF_pred  AURCIFP  AURC Infinity Pred  amount  Area under the urinary excretion rate curve extrapolated to infinity, based on the last predicted excretion rate. 
AURC_PerCentExtrap_pred  AURCPEP  AURC % Extrapolation Pred  %  Percent of AURC_INF_pred that is extrapolated 
AURC_lower_upper  AURCINT  AURC from T1 to T2 (partial AUC)  amount  The area under the urinary excretion rate curve (AURC) over the interval from T1 to T2. 
AURC_lower_upper_D  AURCINTD  AURC from T1 to T2 Norm by Dose  no unit  The area under the urinary excretion rate curve (AURC) over the interval from T1 to T2 divided by Dose 
Rate_last_pred  –  –  amount/time  The values alpha and Lambda_z are those values found during the regression for lambda_z 
Parameters related to sparse NCA
Name  UNITS  DESCRIPTION 

SE_Cmax  amount/volume  Sample standard error of the concentration values at Tmax (standard deviation of the yvalues at time Tmax divided by the square root of the number of observations at Tmax) 
SE_AUClast  time.amount/volume  SE_AUClast = \(\sqrt{Var(\hat{AUC})} = \sqrt{\sum_{i=0}^{m} \frac{w_i^2s_i^2}{n_i}+2 \sum_{i<j} \frac{w_i w_j n_{ij} s_{ij}}{n_i n_j}}\)with \( w_{i} = \begin{cases} \frac{t_1t_0}{2}, & \text{if i=0}\\ \frac{t_{i+1}t_{i1}}{2}, & \text{if i=1, …, m}\\ \frac{t_mt_{m1}}{2}, & \text{if i=m} \end{cases} \) and \( s_{ij} = \sum_{k=1}^{n_{ij}} \frac{(C_{ik}\bar{C_i})(C_{jk}\bar{C_j})}{(n_{ij}1)+(1\frac{n_{ij}}{n_i})(1\frac{n_{ij}}{n_j})}\) where:

SE_AUCall  time.amount/volume  Same as SE_AUClast with m = last observation time 
SE_Max_Rate  amount/time  Same as SE_Cmax with excretion rates 
SE_AURC_last  amount  Same as SE_AUClast with excretion rates 
SE_AURC_all  amount  Same as SE_AUCall with excretion rates 
SE_AUClast, SE_AUCall, SE_AURC_last, SE_AURC_all are available only if the integral method is “linear trapezoidal linear” or “linear trapezoidal linear/log” (because the formula is based on linear calculation of AUC).
Parameter renamings
Starting from the 2023 version of MonolixSuite, default parameter names used in results tables and plots in the graphical user interface and reports do not match the names present in the Name column of the tables above. The names that are used can be customized in the NCA parameters renamings section of Preferences. The section contains two columns:
 Parameter – this column contains parameter names from the tables above,
 Alias – this column contains parameter names used in the interface and the values in cells can be changed.
The Alias column is prefilled with default aliases. By clicking on an alias, PKanalix allows users to input characters. There are several options present, when in the input mode:
 Undo – reverse the last action,
 Redo – redo an undone action,
 Subscript – formats selected text and subsequently entered characters as subscript,
 Superscript – formats selected text and subsequently entered characters as superscript,
 CF – clears formatting of a selected text,
 Cancel – cancels the changes and restores the alias,
 Accept – accepts the changes (changes can be accepted by clicking anywhere in the interface as well).