Overview

QC Calculations are automatic calculations performed on the various Samples of the QCBatch. These calculations automatically add additional dataitems per Parameter on the different Samples. These additional dataitems are often used for evaluation.

Calculations might include:

•	Calculations within a single QC Sample such as a RPD, Relative Percent Difference between the observed value and a nominal expected value.
•	Calculation between successive linked QCSamples such as a Spike QC Sample, and the Sample that was spiked.
•	A calculation that accesses the true value as defined in the Consumable Lot that is referenced from the QCSampleType.
•	Calculations across the group of Unknown Samples such as a blank subtraction that takes a blank value and subtracts off from other Samples near the blank.

The Calculations to be performed are defined in the Calculation Action field (on the QC Method in the QC Method Sample Type tab) for each QC Method Sample Type.

Behind each calculation is an action. This action is executed during Batch creation. The action is responsible for internally adding additional data items for each of the parameters that are present in the Test Methods/Parameter Lists as well as defining the Labvantage calculation syntax that will be executed during data entry.

These additional dataitems can be viewed in the standard data entry page shown here.

QC Calculations are performed real time, during data entry.

Along with the values entered during data entry (in the yellow colored fields) additional parameter values are used to perform the calculations. These values can be defined in the QC Method or by associated Consumable Lots.

The following sections describe each of the QC Calculations provided and any additional parameters needed.

Blank Corrected

Top

Subtracts the Blank's data value from the value of other Samples. Some definitions are in order:

Blank Correction is done on Samples in the Blank Bracket that have the same Data Sets as the Bracket Parent.

Following Blank Correction, the Blank Corrected values are considered "base values". Other QC Calculations (RPD, %Difference, %Recovery, Expected Recovery) are done on the Blank Corrected values.

Additional Parameters

Expected Recovery is calculated from the concentration of the spiking solution, and volumes of the Spike and Unknown Sample.

Additional information associated with the Spike QC Sample Type (spiking and Sample volumes, actual concentrations of different parameters) are used in this calculation.

Expected Recovery accesses the source Sample identified by the "LinkTo" property of the QC Sample Type. This calculation executes when the Data Set in the "LinkedTo" Sample is modified.

Additional Parameters

Calculates percent difference between the recorded and actual value of a Control Sample.

Additional Parameters

Checks the difference between two results. This calculation accesses the "Link To" Sample defined by the QC Sample Type. The calculation executes when the linked Data Set is modified.

	Position	QC Sample Type
	1	Unknown
	2	Control
Blank Bracket ->	3	Blank	<- Bracket Parent
	4	Duplicate
	5	Spike
	6	Unknown
	7	Blank
Blank Bracket ->	8	Blank	<- Bracket Parent
	9	Unknown
	10	Duplicate

1.	Mean/average is derived from all Replicates of a Data Item in a Bracket Parent.
2.	Value of the derived mean is subtracted from the value of all matching Data Items in the Samples within the Blank Bracket.
3.	Blank Corrected Data Item is added to all Samples within the Blank Bracket for which Blank Correction is done. A difference value is also provided.

Sample 001
Parameter	Type	Replicate	Entered Value
Ca	Standard	1	30	<- Average/mean is derived from all Replicates of a Data Item for a Blank.
Ca	Standard	2	10
Ca	Standard	3	24
Z	Standard	1	9
Z	Standard	2	10
Z	Standard	3	11
Ca	Average	1	21.333333	<- Automatically derived average/mean value of the Data Item.
Z	Average	1	10

Parameter	Parameter Type
In the QC Method, QC Sample Type tab, add a "Concentration" Parameter and value for each Parameter to be tested. Or, You can use the Consumables module to obtain these parameter values by defining the following: In the Consumable Type, reference the associated Parameter List in the Consumable Params field. As Consumable Lots are added for this Consumable Type actual values must be defined for these Parameters in the Consumable Params detail. These values are then used by the QCCalcSpikePRecovery calculation.	Concentration
In the QC Method, add the Sample Spike Volume Parameter.	Standard
In the QC Method, QC Sample Type tab, add the Sample Volume Parameter.	Standard

Parameter	Parameter Type	Value
Define one Parameter for each of the Parameters to be tested.	Concentration	Define the actual values for each.
Spike Volume	Standard
Sample Volume	Standard

QC Calculations

Content

Overview

Blank Corrected

Additional Parameters

Expected Recovery

Additional Parameters

IUPAC Recovery Method

Additional Parameters

Expected Concentration Method

Additional Parameters

% Difference

Additional Parameters

% Recovery

Additional Parameters

RPD

Additional Parameters

•	A "Bracket Parent" is a Blank that has Unknown Samples and/or QC Samples below it.
•	A "Blank Bracket" defines a group of Unknown and/or QC Samples beginning immediately below the Bracket Parent and ending at the next Blank.

•	Samples in positions 4 through 7 have the same Data Sets as position 3. Blank Correction subtracts position 3's value from Samples in positions 4 through 7.
•	Samples in positions 9 and 10 have the same Data Sets as position 8. Blank Correction subtracts position 8's value from Samples in positions 9 and 10.

Parameters	Parameter Type	Value
Define one Parameter for each of the Parameters to be tested.	Concentration	Define the actual values for each.
Spike Volume (Spike Percent Recovery only)	Standard
Sample Volume (Spike Percent Recovery only)	Standard