IQ And OQ: What Does This Mean For Thermal Analysis Users?

What does IQ and OQ mean for thermal analysis users, in particular for differential scanning calorimetry ( DSC  ) and thermogravimetric analysis (  TGA  ) users  ?

The installation qualification (IQ) and the operative qualification (OQ) are part of the so-called analytical instrument qualification process (AIQ) in the user’s laboratory to confirm that an instrument is installed correctly, works correctly and produces the expected results. A key term in this context is “demonstration of fitness for purpose.”
Next, we would like to explain in more detail what is behind that, mainly on the basis of USP <1058>, the corresponding chapter in the US pharmacopoeia. UU.

Risk based approach

Depending on the complexity of the instrument or the importance of the measurement, the instruments are classified into 3 groups: A, B and C. However, depending on the purpose for which the device is used, the same type of instrument may belong to More than one group.

Group A includes standard equipment without measuring capacity or user requirement for calibration. If they are obviously working well, no additional qualification will be necessary.

Group B includes instruments that provide measured values ​​or experimental conditions that may affect a measurement and, therefore, require routine calibration, maintenance or performance controls. These instruments may have firmware but no software updated by the user.

Group C includes instruments with a significant degree of computerization and complexity. For such instruments, all qualification elements (see below) are required plus software validation. However, software validation and instrument qualification can be combined into a single activity because software is generally essential to execute the instrument.

In USP 41, only a limited number of instrument examples are given: pH meters and furnaces for group B, as well as mass spectrometers and HPLC instruments for group C. In previous versions of USP, both  DSC  and  TGA  are explicitly classified as group C.

The four qualification phases

These are DQ (Design Qualification), IQ (Installation Qualification), OQ (Operational Qualification) and PQ (Performance Qualification). PQ is also sometimes called “user acceptance test (UAT)”. For complex systems, this framework can be extended using function specifications (FS) and / or factory acceptance tests (FAT), if necessary.

The most important thing is that all the required activities are carried out in a logical order. In addition, all rating activities must be predefined and documented at the same time.

Design qualification

DQ is done before the purchase decision and defines the requirements profile of the DSC  or  TGA device   . This includes the functional and operational specifications, as well as the intended purpose of the instrument and, finally, shows that the selected instrument is appropriate. DQ can be performed by the instrument manufacturer or by the user.

Some laboratories also issue a list of user requirements specifications (URS) that precedes the DQ. In the USSR, future users specify what they want the instrument to do.

Installation Qualification

IQ represents documented evidence that the  particular DSC  or  TGA instrument  , including software, accessories, etc., is delivered as designed and as specified, that the planned environment is adequate and that the instrument is installed correctly. It applies to  new or used DSC  or  TGA instruments  and is carried out after the installation and commissioning of the instrument at the owner’s site.

Operational qualification

OQ follows the installation rating. It is a documented collection of activities with the objective of verifying that the DSC  or  TGA instrument   works correctly in the selected environment and complies with the operational specifications given in the Design Qualification (DQ) and / or user requirements specifications (URS) .

Performance rating

PQ is the last of the four qualification phases and documents the continuous suitability of the DSC  or  TGA instrument   for its intended use in real operating conditions. This generally also involves the use of typical applications on the site and the laboratory test substances themselves. The frequency of the test depends, among others, on the robustness of the DSC  or  TGA device   , the experience and the importance of the analytical method.

Another part of the performance rating is preventive maintenance and documentation of repairs and changes in equipment. Preventive maintenance also includes periodic calibration of the DSC  or  TGA instrument   .


The final responsibility for the qualification of the DSC  or  TGA instrument   rests with the user, while the term user covers not only the operator but also its supervisors, the associated instrument specialists and the administration of the organization. Instrument manufacturers and suppliers can only advise and help.

What NETZSCH offers

However, NETZSCH Analyzing & Testing offers several  services  to help users during the qualification process of   NETZSCH  DSC  or  TG units . These are

  • IQ-OQ documents (in standard version and – optional – customized), including a template for recurring PQ tests
  • Installations with subsequent processing of documents IQ-OQ- (PQ)
  • Maintenance contracts that include the calibration of instruments on a regular basis.

Carried out by experienced and well trained service personnel. For more information, contact your local NETZSCH representative.


by Abdullah Sam
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