A rule in a rule set can do either a conditional substitution or an unconditional substitution, not both.
If a rule set has rules for the same exact non-numeric value, then the last rule is applied.
A rule set can list several non-numeric codes with different substitution rules. These rules are considered independent of each other. For example, if one rule substitutes concentrations < LLOQ with “BQL”, and another rule within the same rule set substitutes all “BQL” values with “0”, concentrations of < LLOQ are shown as BQL and not zero, regardless of the order of the rules.
If a column is mapped to the LLOQ context and a static LLOQ value is defined within the rule set, the static option takes precedence over the mapped LLOQ column.
If a numeric value is entered as a non-numeric code, the tool will search for the exact value with the exact precision before a substitution takes place. The Concentration column is searched unless Status Code is mapped, in which case the Status Code column will be searched.
A rule that resides within the BQL Rules folder can be used in one or more BQL objects. An internal rule, residing within a given BQL object, cannot be used by another object. If the rules are the same there is no difference in the results if an external or internal rule is used.
Only one column can apply rules for the “below LLOQ” concentration.
Common substitution rules
Some common substitution rules for BQL samples are presented in the table below.
The substitution rules are typically defined in standard operating procedures or method sheets for a given company or department. The rules can become more complex when a distinction is made between concentrations that are below the quantification limit (BQL) and below the detection limit (BDL). In general, a substitution rule is defined by the list of possible non-numeric representations for concentration and the values to be substituted for each. One substitution rule for PK analyses is presented below:
