Determining the Frequency of Internal Quality Control at the Point of Care

We all know how important quality control is when performing analysis of patient samples. A new study has created a scoring system for point of care devices based on the type of test being performed and the impact the results can have on patient care.

Overall, four factors were considered:

• The importance of the analyte in diagnosing and monitoring patients
• Type of POCT device
• User-friendliness
• Number of patient samples tested in routine service

The study concentrated on primary healthcare where governance can be difficult to implement and maintain. The first three factors determined the aggregate score for that device and test, leading to recommendations on how frequent quality control should be performed. This has been open to interpretation and a point of conjecture for as long as I can remember, so additional guidance is welcomed, and adoption of the recommendations will be down to point of care leads to decide the appropriateness within their service.

Risk of Harm to Patients

Where POCT expedites clinical decisions, users need to know that results are accurate and their faith in the technology is justified. Of course, quality control data is only part of the overall governance requirements of providing medical devices in a healthcare environment, and training, equipment selection and maintenance, external quality assurance and ongoing competency assessment all play their part.

ISO standards focus on the risk of harm to patients and suggest service providers design a quality assurance programme that is fit for purpose and reflects the device and test being employed. This changes from test to test and across devices. The programme shouldn’t be intrusive or cause delays to care, so the balance between the regularity of actions taken to assure quality and use of the device needs to be balanced appropriately.

Frequency of testing quality materials can range from daily, weekly and monthly. Where risk is high, the study found that higher frequencies of internal quality testing was warranted. This study is the first time the aforementioned factors have been combined to produce a recommended frequency of testing. The study did not mention single use products or lot/batch considerations but guidance can be found here on POCTInnovators.com.

Proposed Frequency (reproduced from source) The following table illustrates the decision rule for classifying frequency of quality material testing.

The scoring system was applied to 17 analytes and 134 different POCT devices (153 analyte-device combinations). The scores for the most frequently used devices is shown below along with the recommendation based on the scoring system (reproduced from source).

a= Risk of harm from inaccurately reporting the analyte, b= Device type, c= Ease of use

By allocating a score to analyte:device combinations taking into account frequency of testing, the study was able to recommend the quality control frequency for a number of point of care tests. As a service provider you may wish to reflect on your own quality processes for devices and analytes, and this study serves as a guide only to the adoption of quality material testing.

Reference/Source

Read the full study here: https://www.degruyter.com/document/doi/10.1515/cclm-2021-1258/html

Point-of-care testing in primary healthcare: a scoring system to determine the frequency of performing internal quality control – https://pubmed.ncbi.nlm.nih.gov/35150123/

Clin Chem Lab Med. 2022 Feb 14;60(5):740-747. doi: 10.1515/cclm-2021-1258. Print 2022 Apr 26.