DQM Control Limits

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DQM Control Limits

The RT_DQM_CONTROL_LIMITS table defines QAPP-specific control limits for the following DQM Checks:

A.Spike Recovery Check

B.Surrogate Recovery Check

C.Relative Percent Difference Check

D.Field Relative Percent Difference Check

E.Field, Lab, or Trip Blank Contamination Check

F.Required Detection Limit Check

G.Percent Relative Standard Deviation Check

 

The Control Limits can be reviewed and edited in the DQM Settings Form as detailed here.

 

When values for particular control limits are supplied in this table, they are used in the relevant DQM Check instead of the control limits supplied by the lab in the DT_RESULTS_QC table.

 

If control limit values are not found in the RT_DQM_CONTROL_LIMITS table for a particular check, then the control limit values from DT_RESULTS_QC are used.

 

If control limit values are not found in either table, then an error is written to the Error tab in the Process Event Form and that result is skipped in that check's processing.

 

For each DQM QAPP, the control limits can be set for general application to MATRIX_CODE, which is a required field. This MATRIX_CODE is matched to DT_SAMPLE.MATRIX_CODE to find the applicable control limits.

 

Control limits can be set for more specific combinations by including values in the ANALYTIC_METHOD, METHOD_ANALYTE_GROUP_CODE and/or CAS_RN fields.
 

DQM.Control.Limits

The process for finding a matching record in RT_DQM_CONTROL_LIMITS is as follows:

1.For Events Created without Specifying a Method Analyte Group (MAG) Look for a record with METHOD_ANALYTE_GROUP_CODE = NULL and

a.A matching MATRIX_CODE, ANALYTIC_METHOD, PREP_METHOD and CAS_RN.

b.If not found, then a matching MATRIX_CODE and 2 of the other 3.

c.If not found, then a matching MATRIX_CODE and 1 of the other 3.

d.If not found, then a matching MATRIX_CODE.

e.If not found, then look in DT_RESULTS_QC and/or RT_HOLDING_TIME for control limits.

2.For Events Created with a Specific MAG Look for a record with:

a.A matching MATRIX_CODE, ANALYTIC_METHOD, METHOD_ANALYTE_GROUP_CODE, PREP_METHOD and CAS_RN.

b.If not found, then a matching MATRIX_CODE and 3 of the other 4.

c.If not found, then a matching MATRIX_CODE, and 2 of the other 4.

d.If not found, then a matching MATRIX_CODE and 1 of the other 4.

e.If not found, then a matching MATRIX_CODE.

f.If not found, then look in DT_RESULTS_QC and/or RT_HOLDING_TIME for control limits.

 

Note: If a more specific combination of ANALYTIC_METHOD, etc. is added to RT_DQM_CONTROL_LIMITS, be sure to specify all of the control limits being used, even if they are the same as those listed in less specific combinations. For example, to change the value for the matrix spike columns in the more specific case, the lab control spike and surrogate column data must still be included, even if it is the same as the less specific case.

 

A. Spike Recovery Check

 

Use the following columns in the RT_DQM_CONTROL_LIMITS table to define the acceptable spike recovery range, where "lcl" denotes the lower control limit and "ucl" denotes the upper control limit, and "upper_cutoff" denotes the upper rejection limit..

 

Lab Control Spike (LCS) Samples

RT_DQM_CONTROL_LIMITS
(if populated)

DT_RESULT_QC
(if value in RT table not numeric or populated)

lcs_recovery_lcl

lcs_recovery_ucl

(need both to be used)

qc_spike_lcl

qc_spike_ucl

(both)

lcs_rec_lower_cutoff; defaults to #

0

lcs_rec_upper_cutoff; defaults to #

999.99

 

Matrix Spike (MS) Samples

RT_DQM_CONTROL_LIMITS
(if populated)

DT_RESULT_QC
(if value in RT table not numeric or populated)

ms_recovery_lcl

ms_recovery_ucl

(need both to be used)

qc_spike_lcl

qc_spike_ucl

(both)

ms_rec_lower_cutoff; defaults to #

0

ms_rec_upper_cutoff; defaults to #

999.99

 

B. Surrogate Recovery Check

 

Use the following columns in the RT_DQM_CONTROL_LIMITS table to define the acceptable surrogate recovery range, where “lower_cutoff” denotes the lower rejection limit, "lcl" denotes the lower control limit, "ucl" denotes the upper control limit, and "upper_cutoff" denotes the upper rejection limit.

 

RT_DQM_CONTROL_LIMITS
(if populated)

DT_RESULT_CONTROL_LIMITS
(if RT table not populated)

surr_recovery_lcl

surr_recovery_ucl

(need both to be used)

qc_spike_lcl

qc_spike_ucl

(both)

surr_recovery_lower_cutoff

rt_holding_time.lower_surrogate_cutoff,
else defaults to 0.0

surr_rec_upper_cutoff

defaults to 999.99

 

To define control limits for individual surrogate recoveries, create a record for each surrogate [with the QAPP code, matrix, and analytic method, and prep_method (if applicable) populated] and populate:

RESULT_TYPE_CODE = ‘SUR’ and

CAS_RN = the surrogate CAS_RN.

 

Surrogate Recovery Associated Results

 

The Surrogate Recovery Check adds a qualifier to Associated Results from the same DT_TEST.TEST_ID. For some surrogates, such as acid and base surrogates for analytic method SW8270, a more specific list of associated results is desired. To create a surrogate-specific list of CAS_RNs to associate, enter the following into the RT_DQM_CONTROL_LIMITS table for each analyte to be associated, repeated for each surrogate:

DQM_QAPP_CODE = 'QAPP_SURR_ASSO_CAS_RN'  

oRather than requiring this list to be repeated for each QAPP, DQM uses a single DQM_QAPP_CODE just for these lists. The user can modify this DQM QAPP at any time; however, you cannot use this same QAPP_CODE with different lists for a given database.

MATRIX_CODE = a valid MATRIX_CODE from RT_MATRIX  

oThis column is required as part of the primary key for this table, but the matrix code is NOT used to match Associated Results from this list.

ANALYTIC_METHOD = NULL (or the analytic method for the surrogate)

oThis column may be populated for informational purposes, but the analytic method is NOT used to match Associated Results from this list.

RESULT_TYPE_CODE = NULL (or the result type code for a standard result in the current database, such as 'TRG')

oThis column may be populated for informational purposes, but the result type code is NOT used to match Associated Results from this list.

CAS_RN = the CAS_RN of analyte to be associated

o If there are multiple surrogates, these records need to be repeated for each surrogate.

SURR_ASSO_CAS_RN = the CAS_RN of the surrogate

 

C. Relative Percent Difference Check

 

For the Relative Percent Difference (RPD) check, use the following fields to define different RPD control limits for Lab Control Spike Duplicates, Matrix Spike Duplicates, and Lab Duplicates.

 

RT_DQM_CONTROL_LIMITS
(if populated)

DT_RESULT_QC
(if RT table not populated)

lcs_dup_rpd_cl

qc_rpd_cl

ms_dup_rpd_cl

qc_rpd_cl

lab_dup_rpd_cl

qc_rpd_cl

 

D. Field Relative Percent Difference Check

 

The Field RPD check already has the following parameters for RPD control limits:

rpd_control_limit_soil

rpd_control_limit_water

rpd_control_limit_other

 

To provide a different control limit for a method analyte group, ANALYTIC_METHOD, or CAS_RN, populate the FIELD_DUP_RPD_CL column. This will override the Field RPD Check control limit parameter for the given matrix.

 

E. Field, Lab, or Trip Blank Contamination Check

 

Each check for Blank Contamination already has a multiplier parameter to control how the check marks associated results using the following rules. The multiplier must be an integer.

 

Prior to Release 7.21.2:

1.RESULT > BLANK * MULTIPLIER = Qualify an associated result if sample result > multiplier * concentration detected in the associated blank.

2.RESULT < BLANK * MULTIPLIER = Qualify an associated result if sample result < multiplier * concentration detected in the associated blank. Assuming the qualifier for this rule = “U”, then this will indicate the result is non-detect.

 

To provide a different multiplier for a method analyte group, ANALYTIC_METHOD or CAS_RN, populate the BLANK_MULTIPLIER column. This will override the Blank Contamination Check multiplier parameter.

 

As of Release 7.21.2:

1.RESULT/DF >= QL OR >= BLANK * MULTIPLIER = Qualify an associated result if sample result divided by the dilution factor is greater than or equal to the quantitation limit (defined in Global parameters by the nondetect_detection_limit) or greater than or equal to the concentration detected in the associated blank multiplied by the multiplier.

2.RESULT/DF >= QL & < BLANK * MULTIPLIER = Qualify an associated result if the sample result divided by the dilution factor is greater than or equal to the quantitation limit (defined in Global parameters by the nondetect_detection_limit) and is less than the concentration detected in the associated blank multiplied by the multiplier.

3.RESULT/DF >= BLANK * MULTIPLIER= Qualify an associated result if the sample result divided by the dilution factor is greater than or equal to the concentration detected in the associated blank multiplied by the multiplier.

 

F. Required Detection Limit Check

 

Enter the "project required detection limits" into the REQUIRED_DETECT_LIMIT and REQUIRED_DETECT_LIMIT_UNIT columns of the RT_DQM_CONTROL_LIMITS table for each Analytic Method and/or CAS_RN in the analytic results of the database.

 

G. Percent Relative Standard Deviation (RSD) Check

 

Enter the Relative Standard Deviation (RSD) Control limits for each Analytic Method, Prep Method, and/or CAS_RN for the following:

Field Replicate RSD:  field_rsd

Laboratory Replicate RSD: ld_rsd

Matrix Spike RSD: ms_rsd

Laboratory Control Sample RSD: lcs_rsd