Lab Blank Contamination Check

The DQM Check for Lab Blank Contamination identifies detected concentrations of target analytes in laboratory blanks. If a detected analyte in a laboratory blank is also contained in an associated sample at a similar level as that in the blank, DQM will qualify the associated sample result.

Check

The check name is EarthSoft.DQM.LabBlankContamination.

Parameters

This check uses the following six check parameters:

1.LabBlankSampleType - the sample_type_code used for laboratory blanks – defaults to LB.

2.MethodBlankSampleType - the sample_type_code used for laboratory method blanks – defaults to MB.

3.Multiplier – used by DQM to determine if a result can be qualified as non-detect - defaults to 1 if no value supplied. Must be an integer.

4.Common_lab_multiplier – used by DQM to determine if a result identified as a common laboratory contaminant can be qualified as non-detect; depends on CAS_RN field being populated and defaults to 2 if no value is supplied. Must be an integer.

5.Flag_blank – if TRUE, the laboratory blanks are also qualified – defaults to TRUE.

6.normal_sample_types – the sample_type_codes to be used for standard association of laboratory blanks – defaults to “N”.

Using a value for multiplier from RT_DQM_CONTROL_LIMITS is discussed in more detail here.

This check uses three Global Parameters:

1.reportable_result - dt_result.reportable_result values to include in DQM datasets

2.result_type_code - dt_result.result_type_code to include in DQM datasets

3.test_type_batch - at_test_batch_assign.test_batch_type to include in DQM dataset

Additionally, for EQuIS build 7.21.2 and later, this check uses nondetect_detection_limit from Global Parameters.

Note:

•The default value is used if there is no record in RT_DQM_CHECK_PARAM for an input parameter.

•The default value is used if the PARAM_VALUE is NULL in RT_DQM_CHECK_PARAM.

Rules

For DQM Version 7.21.1 and earlier versions:

There are three rules:

1.BLANK CONTAMINATION = Qualify the result in the blank sample if a concentration is detected and the FLAG_BLANK parameter = TRUE.

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

3.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. When Completing an Event and saving qualifiers, there is also an option to set DETECTED_YN to "N" for all results with a "U" qualifier.

For DQM Version 7.21.2 and later versions:

In addition to the 3 rules available in 7.21.1 and earlier versions, there are six new rules available:

1.BLANK CONTAMINATION < QL - Contamination detected in the Blank less than the Quantitation Limit

2.BLANK CONTAMINATION >= QL - Contamination detected in the Blank greater than or equal to the Quantitation Limit.

3.RESULT/DF < QL - Associated Result / Dilution Factor < Quantitation Limit.

4.RESULT/DF >= QL OR >= BLANK * MULTIPLIER - For Blank Conc < QL, Associated Result / Dilution Factor >= Quantitation Limit OR >= multiplier * concentration detected in the associated blank.

5.RESULT/DF >= QL & < BLANK * MULTIPLIER - For Blank Conc >= QL, Associated Result / Dilution Factor >= Quantitation Limit AND < multiplier * concentration detected in the associated blank.

6.RESULT/DF >= BLANK * MULTIPLIER - For Blank Conc >= QL, Associated Result / Dilution Factor >= multiplier * concentration detected in the associated blank.

If all 9 blank rules exist in a DQM QAPP, only the 6 new rules available starting in version 7.21.2 will be used by DQM. In order for the 3 rules available prior to 7.21.2 to be used by DQM, only these 3 rules should be included in the DQM QAPP.

Associated results are found by:

1.Matching results (with detected concentrations only) by Method, Fraction, CAS_RN and TEST_BATCH_ID. If matching samples are found, the process stops.

2.If no matching results are found in Step 1, results (with detected concentrations only) are matched by Method, Fraction, CAS_RN and LAB_SDG.

Note: To use the TEST_BATCH_ID, it must be added to DT_TEST_BATCH and then the TEST_ID of the blank sample, and all of the associated TEST_IDs are added with their TEST_BATCH_ID and TEST_BATCH_TYPE to AT_TEST_BATCH_ASSIGN (usually done by EDP format).

Use of Reason Codes with the rules is discussed here.

Exceptions

For DQM Version 7.21.1 and earlier versions:

For Lab Blanks

•Review blanks if Flag_blank = TRUE

•Review results with DT_SAMPLE.SAMPLE_TYPE_CODE = LabBlankSampleType and MethodBlankSampleType

•Qualify a result in a lab blank if reportable_result = Y and detect_flag=Yes

The dqm_remark for this exception is: Contamination detected in this Blank.

For Associated Samples

•Review results with DT_SAMPLE.SAMPLE_TYPE_CODE = LabBlankSampleType and MethodBlankSampleType

•Qualify a result in an associated sample if reportable_result = Y and detect_flag=Yes and if sample result > multiplier * concentration detected in the associated blank.

An example dqm_remark for this exception is: [5 > 4 * 1] Sample result > multiplier * concentration detected in the associated blank (sample_id:3281206, test_id:3281223, cas_rn:129-00-0)

•Qualify a result in an associated sample if reportable_result = Y and detect_flag=Yes and if sample result < multiplier * concentration detected in the associated blank.

An example dqm_remark for this exception is: [5 < 6 * 1] Sample result < multiplier * concentration detected in the associated blank (sample_id:3281211, test_id:3281224, cas_rn:7440-66-6)

For DQM Version 7.21.2 and later versions:

For Lab Blanks

•Review blanks if Flag_blank = TRUE

•Review results with DT_SAMPLE.SAMPLE_TYPE_CODE = LabBlankSampleType and MethodBlankSampleType

•Qualify a result in a lab blank if reportable_result = Y and detect_flag=Yes

1.If BLANK CONTAMINATION < QL - the apply_remark is “Contamination detected in the Blank less than the Quantitation Limit.”

An example dqm_remark for this exception is: “[0.5 < 1] Blank result < quantitation limit in this blank.”

2.BLANK CONTAMINATION >= QL - the apply_remark is “Contamination detected in the Blank greater than or equal to the Quantitation Limit.”

An example dqm_remark for this exception is: “[8 >= 1] Blank result >= quantitation limit in this blank.”

For Associated Samples

•Review results with DT_SAMPLE.SAMPLE_TYPE_CODE = LabBlankSampleType and MethodBlankSampleType

•Qualify a result in an associated sample if reportable_result = Y and detect_flag=Yes according to the following

1.RESULT/DF < QL - the apply_remark is “Associated Result from: Associated Result / Dilution Factor < Quantitation Limit.”

An example dqm_remark for this exception is: “[0.3 / 1 < 1] Sample result / dilution factor < quantitation limit in this associated blank: (sys_sample_code:AQ_SAMPLE1_RC_TB, analytic_method:SW6010, cas_rn:7440-28-0).”

2.RESULT/DF >= QL OR >= BLANK * MULTIPLIER – the apply_remark is “Associated Result from: For Blank Conc < QL, Associated Result / Dilution Factor >= Quantitation Limit OR >=concentration detected in the associated blank.”

An example dqm_remark for this exception is: “[5 / 1 >= 1 * 0.5] Sample result / dilution factor >= multiplier * concentration detected in this associated blank: (sys_sample_code:AQ_SAMPLE1_RC_TB, analytic_method:SW6010, cas_rn:7440-28-0)”

3.RESULT/DF >= QL & < BLANK * MULTIPLIER – the apply_remark is “Associated Result from: For Blank Conc >= QL, Associated Result / Dilution Factor >= Quantitation Limit AND < multiplier * concentration detected in the associated blank.

An example dqm_remark for this exception is: “[10 / 1 >= 1] AND [10 / 1 < 2 * 8] Sample result / dilution factor >= quantitation limit AND < multiplier * concentration detected in this associated blank:(sys_sample_code:AQ_SAMPLE1_RC_TB, analytic_method:SW6010, cas_rn:7782-49-2).”

4.RESULT/DF >= BLANK * MULTIPLIER – the apply_remark is “Associated Result from: For Blank Conc >= QL, Associated Result / Dilution Factor >= multiplier * concentration detected in the associated blank.

An example dqm_remark for this exception is: “[10 / 1 >= 1 * 8] Sample result / dilution factor >= multiplier * concentration detected in this associated blank: (sys_sample_code:AQ_SAMPLE1_RC_TB, analytic_method:SW6010, cas_rn:7782-49-2).”

Errors

1.Blank unit error

This check includes an internal unit conversion function, which allows blanks with units for liquids to be compared to results for soil samples. This internal function includes:

•ug/L to mg/kg

•ug/L to ug/kg

•mg/L to mg/kg

•mg/L to ug/kg

Any combination of units found in RT_UNIT_CONVERSION_FACTOR will also be used.

The following error occurs if the units differ and none of the above conversion factors apply:

“Associated result has units ({0}) that do not convert to units of blank result ({1}).”

For this check to work, a record must be added to RT_UNIT_CONVERSION_FACTOR for that combination.

2.Result Numeric is null.

If the RESULT_NUMERIC column is null in the blank or the associated sample for a result, the following error message will be created:

“The RESULT_NUMERIC column is NULL in blank or associated result.”