The Rules tab contains optional settings that apply to the Lambda Z calculation in Plasma and Urine models. (The Rules tab does not apply to Slope1 and Slope2 in Drug Effect models.)
Lambda Z Rules for Best Fit method: These optional rules are used only in the automatic selection of Lambda Z.
In the Max # of points field, specify the maximum number of points that can be used in the best-fit method for Lambda Z.
If a value is specified, the NCA engine will not consider time ranges that contain more than the specified number of points when finding the best Lambda Z. The entered value must be at least 3.
In the Start Time Not Before field, specify the minimum start time that can be used in the best-fit method for Lambda Z.
If a value is specified, the NCA engine will not consider time ranges that start before this minimum start time when finding the best Lambda Z.
Lambda Z Acceptance Criteria: These optional acceptance criteria apply to both the Best Fit method and the Time Range method. These rules are used to flag profiles (described further below) where the Lambda Z final parameter does not meet the specified acceptance criteria.
1. Specify the minimum value of Rsq_adjusted that indicates an acceptable fit for Lambda Z in the Rsq_adjusted field.
Value must be between 0 and 1.
2. Use the pull-down menu to select whether to use AUC_%Extrap_obs or AUC_%Extrap_pred (or, for Urine models, AURC_%Extrap_obs or AURC_%Extrap_pred) when indicating the acceptable fit for Lambda Z.
In the field, enter the maximum value to use. Value must be between 0 and 100.
3. In the Span field, specify the minimum span or number of half-lives needed for the Lambda Z range to be acceptable.
Values must be positive.
If a profile does not have an acceptable Lambda Z fit as specified by the acceptance criteria, an output flag value of ‘Not_Accepted’ is used to flag each of the criterion that is not met by that profile. In addition, a flag value of ‘Missing’ is used to flag all profiles where the parameter used for acceptance cannot be computed. Note that all computed results for flagged profiles are still included in the output but the final parameters for these profiles will be marked by the flags. All profiles that have an acceptable Lambda Z fit (i.e., meet the acceptance criterion) will have the flag value of ‘Accepted’.
The flags appear in columns in the Final Parameters Pivoted output worksheet immediately after the column for the parameter used for the acceptance criterion. The flag column names are ‘Flag’ appended with the parameter name used for acceptance, e.g., Flag_Rsq_adjusted, Flag_Span. To remove the profiles failing to meet the acceptance criteria from the output, the Final Parameters Pivoted worksheet can be processed by the Data Wizard to delete these profiles, by filtering on the flag values of ‘Not_Accepted’ and excluding these rows. Note that the Flag columns do not appear in the output when there are no flagged profiles, that is, when all profiles meet the acceptance criterion or when the acceptance criterion is not set.
In the Final Parameters output worksheet and in the Core Output text, where the final parameter output is stacked, the flag names and values appear below the acceptance parameter. If the acceptance parameter is selected to not be included in the worksheet output in the “Parameters Names” setup, the corresponding flag will also not be included in the worksheet.
See the “Data checking and pre-treatment” section for a list of cases that also produce flagged output.