Reporting the sum of impurities above LOQ with an ENUM


I need to report  the total amount of impurities above the LOQ for several known impurities. 

 I have created a Boolean CF with a 0 translation of Below QL, and 1 as the actual %.  Results for individual results is working fine. 

I tought I could calculate the total impurities above the LOQ in my report using the SUM, but total result is not reported.  Is it because the report table contains text (as Below LOQ)?

Could it be possible to calculate the sum using a ENUM?  Any ideas??



  • If you used database codes to generate text in tables, then the function will sum the code as well using the -60,00X value. If you used a boolean field as text to insert the below QL, then the summation field is not going to know what to do with that result. 

    you will need to create a duplicate custom field that removes either the database codes or the text inserted with the boolean field. The summation field can then run off the custom field that clears the database codes / text. 
  • edited August 2020
    You could create two custom fields to get around this. First Peak, Bool GT(Area,0.10) or whatever your LOQ is.You could use CConst1 if the components have varying LOQs.  Have the Use as set to Value, and the false translation is 0 and the true translation is 1. Second Peak Real Custom field, Area*CF_1 which will either return the Area or a 0. Sum this column in your report method for the sum of all known impurities which satisfy the argument in your first Bool custom field. 

    Or a Result Real custom field which sums up the total impurities GT LOQ for each sample injection. SUM(% Area*(GT(% Area,0.1)). 
  • Or you can use Impurity Response in combination with the Impurity tab in the processing method and have no need of a CF at all.

    Caution: Empower rounds a result to the precision displayed in the limit field(s) used on the Impurity tab and only reports results that are ABOVE that value, so do throw some extra zeroes in there (places like ICH Reporting threshold - if you're using a USP 0.05 LOQ, for example, enter it as 0.05000 to minimize the chance of having something left out).
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