DQM FAQs: Blank Checks & Logic

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DQM FAQs: Blank Checks & Logic

If I set a parameter multiplier to 10 within the Lab Blank Contamination check, but do not specify a method, does it apply to all methods?
 

How can blanks be associated to all the samples within the same laboratory work order number?
 

Are common lab contaminants identified in the template QAPP? If not, how can I identify common lab contaminants in my QAPP?
 

How do we set DQM to flag a sample as non-detect when a sample hit and a blank hit are both under the reporting limit, without necessarily using the multiplier rule in all cases?

 

Question: If I set a parameter multiplier to 10 within the Lab Blank Contamination check but do not specify a method, does it apply to all methods?

Answer: For any of the blank contamination checks, the multiplier is applied to all analytical methods. DQM includes functionality to set a different multiplier for an individual analyte by populating the desired multiplier value for the common_lab_multiplier parameter for each applicable blank contamination check listed in RT_DQM_CHECK_PARAM for every analyte that requires a different multiplier. Additionally, the RT_DQM_CONTROL_LIMITS table allows the blank multiplier to be adjusted on a method/matrix level with an option of defining to the individual analyte level.

 

Question: How would we be able to associate blanks to all the samples within the same laboratory work order number?

Answer: DQM has built-in logic to make associations dependent upon the sample_type (e.g. field blank, trip blank, or laboratory blank) as follows:

 

1.Field Blank Associated results are found by:

a.Matching samples by FIELD_SDG. If matching samples are found, the process stops.

b.If no matching samples are found, samples are matched by CHAIN_OF_CUSTODY (COC), then

c.If no matching samples are found, samples are matched by TEST_BATCH_ID.
 

2.Laboratory Blank Associated results are found by:

a.Matching samples by TEST_BATCH_ID. If matching samples are found, the process stops.

b.If no matching samples are found, samples are matched by TEST_BATCH_ID.
 

3.Trip Blank Associated results are found by:

a.Matching samples by COC. If matching samples are found, the process stops.

b.If no matching samples are found, samples are matched by FIELD_SDG.

 

Refer to the help article, DQM Check for Blank Contamination.

 

Question: Are common lab contaminants identified in the template QAPP? If not, how can I identify common lab contaminants in my QAPP?

Answer: Yes, the DQM Starter QAPP includes three examples (i.e. acetone, methylene chloride, and 2-butanone) of common lab contaminants for the field blank, trip blank, and lab blank contamination checks in RT_DM_CHECK_PARAM. While the DQM Starter QAPP includes some examples of how to configure these parameters, the exact parameters should be defined per QAPP based on project needs.

 

Question: How do we set DQM so that when a sample hit and a blank hit are both under the reporting limit, DQM flags the sample as a non-detect (without necessarily using the multiplier rule)?

Answer: DQM does not have a rule for the blank contamination checks to evaluate the detected concentration in the blank and sample and compare these values to the reporting limit. Until such time as this rule is added to the blank check, as a suggestion, set the parameter for the multiplier = 1 for all blank contamination checks (e.g. field blank, trip blank, lab blank) in the DQM QAPP EDD, and after creating and running a DQM Event, review and manually update the apply qualifier in the Exceptions by Check for blank contamination in the DQM Event Review Form to make additional qualifications.