Relative Percent Difference III

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Relative Percent Difference III

Report Name: Relative Percent Difference III (example)

File Name: EarthSoft.Reports.Library.93818.dll

Dependencies: N/A

Software: EQuIS Professional and EQuIS Enterprise

Source: EQuIS Professional install

Language: English

Output Type: Excel1


Description: The Relative Percent Difference III Report determines the difference between analytical results for up to three samples. This report can be used to compare sample results from different laboratories or locations.


Installation Instructions: This report assembly is part of the EQuIS Professional installation. No additional installation steps are necessary.



Users can select up to three different samples by selecting the SYS_SAMPLE_CODE for each.


The Date Range: The Start parameter requires input of the SAMPLE_DATE to populate the list of samples for user selection. The Sample information>SYS_SAMPLE_CODE section only lists SYS_SAMPLE_CODEs with SAMPLE_DATEs during the date indicated in Date>Start + one additional day.


The Report Tab compares the analytical results against the laboratory Practical Quantitation Limit (PQL) of the analyte(s) and any resulting differences encountered in the primary, secondary and tertiary sampling. The RPD is calculated as the absolute value of the difference between original and replicate samples divided by the average, and then expressed as a percentage.


The report checks the results for each analyte and determines if the analyte falls into a defined RPD control limit category. The RPD control limits can be defined by the report parameter selections, and by default are:


Pass- RPD is less than or equal to 30%

Pass-1- RPD is greater than 30%, and the Analysis results are less than 10 times the limit of reporting (LOR)

Pass-2- RPD is between 30% and 50%, and the Analysis results are between 10 and 20 times the LOR


If the RPD exceeds the control limits, it is highlighted.



If the units of measurement for the primary, duplicate, and triplicate samples are different, select Unit(s) or Analyte\Analyte Group(s) to unify units (and ensure necessary unit conversion factor(s) is present).

The Relative Percent Difference Report involves multiple calculations; the processing time may take longer than expected. To avoid problems with delay, narrow the data input and/or extend the database connection timeout (see Timeout Error).

This report requires related primary and duplicate and/or triplicate sample, test, and result data; matching units and/or unit conversion factors present.




Report Parameters



Parameter for selecting individual locations.


Parameter for selecting location groups.

Sample Information

Date Range

Parameter section to select the sample start date.

Sys Sample Code

Original Sys Sample Code (required)

Select the SYS_SAMPLE_CODE which indicates that this is the original sample.

Duplicate  Sys Sample Code (required)

Select the SYS_SAMPLE_CODE which indicates that this is a duplicate sample.

Triplicate  Sys Sample Code

Select the SYS_SAMPLE_CODE which indicates that this is a triplicate sample.


Parameter for selecting sample matrix.


Parameter for selecting analtye groups and individual analytes.


Parameter for selecting fraction.


Selection for analyte units.


Parameter selection for one or more task(s).

Delivery Group(s)

Parameter seletion for the delivery group.

Reportable Result(s)

Parameter for selecting reportable results.

DQM Status

Parameter for selecting the DQM status.

Detection Limit

Reporting Limit (required)

Select which reporting limit you desire to use (reporting_detection_limit, method_deteciton_limit, etc.)

Non-detect multiplier

Indicate the non-detect multiplier. Default: 0.5

Non-detect handling

Select how non-detects are handled: eliminate non-detects or show all.

Lower Limit (required)

Indicate the lower limit of the detection limit multiplier standard. Default: 10

Upper Limit (required)

Indicate the upper limit of the detection limit multiplier standard. Default: 20

Relative Percent Difference

RPD lower limit (required)

Indicate the lower limit of the relative percent difference standard. Default: 30

RPD upper limit (required)

Indicate the upper limit of the relative percent difference standard. Default: 50


1Excel report output requires a valid license of Microsoft Excel to view the output.