<< Click to Display Table of Contents >> ## DQM Check for RPD and ABS DIFF |
Copyright © 2020 EarthSoft, Inc • Modified: 21 Feb 2020 |

Check for Relative Percent Difference (RPD) and Absolute Difference (run independently) values for field duplicate sample results that fall outside Quality Control (QC) limits.

It is important that RT_MATRIX.MEDIUM_CODE be populated for this check to work properly. Note that DT_RESULT_QC is not used for this check.

Check name is EarthSoft.DQM.RPD_Abs_Diff_Field = Field Dup RPD / ABS DIFF.

This check uses the reportable_result, result_type_code and test_batch_type parameters from Global Parameters. There are 12 other parameters:

•abs_diff_multiplier – Multiplier used with detection limit to determine when to calculate and check the Absolute Difference as described in the FIELD DUPLICATE ABS DIFF rule below. Defaults to 5.

•abs_diff_multiplier_other – Multiplier for other samples used with detection limit to check the Absolute Difference for the FIELD DUPLICATE ABS DIFF rule as described below. Defaults to 1.

•abs_diff_multiplier_soil – Multiplier for soil samples used with detection limit to check the Absolute Difference for the FIELD DUPLICATE ABS DIFF rule as described below. Defaults to 2.

•abs_diff_multiplier_water – Multiplier for water samples used with detection limit to check the Absolute Difference for the FIELD DUPLICATE ABS DIFF rule as described below. Defaults to 1.

•one_detect_one_ND – Parameter to determine what to do when one of the results has a detected concentration and the other one is non-detect. Choices described in NON_DETECT rules below. Defaults to "CALC".

•medium_code_soil – RT_MATRIX.MEDIUM_CODE for DT_SAMPLE.MATRIX_CODE for soil samples. Defaults to “Soil”.

•medium_code_water – RT_MATRIX.MEDIUM_CODE for DT_SAMPLE.MATRIX_CODE for water samples. Defaults to “Water”.

•rpd_control_limit_other – RPD control limit for other samples. Defaults to 25.

•rpd_control_limit_soil – RPD control limit for soil samples. Defaults to 35.

•rpd_control_limit_water – RPD control limit for water samples. Defaults to 20.

•rpd_multiplier – Multiplier used with detection limit to determine when to calculate and check the Relative Percent Difference as described in the FIELD DUPLICATE RPD rule below. Defaults to 1.

•sample_type_Field_Dup – Defaults to “FD”.

Notes: •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 for this parameter in RT_DQM_CHECK_PARAM. |

There are four rules and the first steps are:

Step 1: Find the samples with DT_SAMPLE.SAMPLE_TYPE = sample_type_Field_Dup. Then:

Step 2: Find the parent sample for each field duplicate using DT_SAMPLE.PARENT_SAMPLE_CODE or DT_FIELDQC_BATCH_PARTNER.QC_SAMPLE_ID.

Step 3: Process each CAS_RNs result for both samples. If both results are non-detect, skip to the next pair of results. If both have detected concentrations, then process these two rules:

1."FIELD DUPLICATE RPD"

a.If, for either result, DT_RESULT.RESULT_NUMERIC >= rpd_multiplier * DT_RESULT.REPORTING_DETECTION_LIMIT, then calculate RPD and:

i.If the MEDIUM_CODE of DT_SAMPLE.MATRIX_CODE = medium_code_soil, then qualify the results if RPD> rpd_control_limit_soil

ii.If the MEDIUM_CODE of DT_SAMPLE.MATRIX_CODE = medium_code_water, then qualify the results if RPD> rpd_control_limit_water

iii.Otherwise, if MEDIUM_CODE is different or NULL, qualify the results if RPD > rpd_control_limit_other

2. "FIELD DUPLICATE ABS DIFF"

a. If, for either result, DT_RESULT.RESULT_NUMERIC <= abs_diff_multiplier * DT_RESULT.REPORTING_DETECTION_LIMIT, then calculate Abs Diff and:

i. If the MEDIUM_CODE of DT_SAMPLE.MATRIX_CODE = medium_code_soil, then qualify the results if Abs Diff > abs_diff_multiplier_soil

*DT_RESULT.REPORTING_DETECTION_LIMIT

ii. If the MEDIUM_CODE of DT_SAMPLE.MATRIX_CODE = medium_code_water, then qualify the results if Abs Diff > abs_diff_multiplier_water

*DT_RESULT.REPORTING_DETECTION_LIMIT

iii. Otherwise, if MEDIUM_CODE is different or NULL, qualify the results if Abs Diff > abs_diff_multiplier_other *DT_RESULT.REPORTING_DETECTION_LIMIT

If one result has a detected concentration and the other is non-detect, then the one_detect_one_ND parameter provides three choices:

1."IGNORE" = Skip to the next pair of results.

2."QUALIFY" = Apply the Qualifier from the "FIELD DUPLICATE RPD NON_DETECT" rule to both results.

3."CALC" = Use the same two processes as above, but:

a.Use DT_RESULT.REPORTING_DETECTION_LIMIT in place of DT_RESULT.RESULT_NUMERIC for the non-detect result.

b.When the "FIELD DUPLICATE RPD" rule calls for the results to be qualified, use the qualifier from the "FIELD DUPLICATE RPD NON_DETECT" rule.

c.When the "FIELD DUPLICATE ABS DIFF" rule calls for the results to be qualified, use the qualifier from the "FIELD DUPLICATE ABS DIFF NON_DETECT" rule.

Note: The equation for RPD = 100 * ABS_VAL(DuplicateResult - ParentResult) / (0.5 * ABS_VAL(DuplicateResult + ParentResult)). |