by JAMES CRILLY - QC MARKETING MANAGER - RANDOX LABORATORIES LTD.
Introduction to POCT
Point of care testing (POCT) refers to testing that is performed near or at the site of a patient with the result leading to a possible change in the care of the patient. The popularity and demand of POCT has been growing rapidly, however, this should come as no surprise as there are many advantages to POCT, for example, the convenience of being able to obtain a rapid result at the patient’s bedside, thus allowing immediate action, saving time and improving the potential outcome for the patient.
Although there are many benefits of using POCT devices in terms of their convenience, these benefits are only true if the results produced are both accurate and reliable. Ensuring accuracy and reliability is the primary responsibility of Quality Control.
Importance of Quality Control for POCT Devices
ISO 15189 states that “Quality Control materials shall be periodically examined with a frequency that is based on the stability of the procedure and the risk of harm to the patient from an erroneous result” (1). Therefore, when implementing a QC strategy for POCT devices the risk of harm to the patient should be the foundation of the plan: where and why do errors occur and what are the consequences of an erroneous result to the patient? It is important to balance the risk of harm to the patient with the stringency of the QC procedure applied. Inaccurate results can have serious implications for the patient including misdiagnosis and/or inappropriate or incorrect medical procedures being carried out unnecessarily, resulting in monetary implications for the hospital.
POCT procedures have been previously shown to be less stable than those run within the laboratory. A recent study found that the most common phase for errors in POCT was analytical, with 65.3% of errors occurring during this phase. (2) Conversely, in laboratory based testing the analytical phase is the least common source for errors (3) thus, highlighting the importance of QC procedures for POCT devices while also outlining how the potential risk of harm to a patient may be greater for POC tests compared to those performed on laboratory based analyzers. This study also revealed that the potential impact of quality control error on a POCT device having a moderate adverse impact on patient outcome was 14.7% (2), demonstrating that for POCT devices there is larger room for error and a greater need for quality control.
In 2006 a new ISO standard; ISO 22870 was released specifically for POCT titled: “POCT – Requirements for quality and competence” (4). ISO 22870 advises that where available, Internal Quality Control and participation in an External Quality Assessment scheme is required in the point of care setting. ISO 22870 is designed to be used in conjunction with IS0 15189.
Choosing IQC material that’s appropriate for use with POCT devices
All POCT devices should run third party IQC samples. It is important to choose IQC material that fully meets the needs of the laboratory.
When implementing an IQC strategy it is important to take into consideration the differing designs of the device and potential risk of harm of the patient. When choosing an appropriate QC material look for the following features:
- Ease of use – many samples are available in a ‘liquid-ready-to-use’ format which require no preparation. This format can be conveniently stored at +2 to +8o C meaning it can be stored safely on the ward rather than in a laboratory freezer.
- A matrix similar to the patient sample – choose samples that are as close to a human sample as possible, in-line with ISO15189 regulations.
- Clinically relevant concentrations – analytes should be available at clinically significant concentrations to accurately validate patient sample results.
- Accurately assigned - method/ instrument specific target values and ranges should be accurately assigned.
- Third party – ISO 15189 recommends quality control material is from a third-party source.
Additional Software Available
Perhaps a reason for the higher rate of error associated with a POCT device is due to a lack of responsibility on behalf of the staff performing the POCT. Ultimately, responsibility should lie within the laboratory but how can the quality of results released by POCT devices be managed when the people performing the tests are spread out in a hospital setting, and out of direct view of the laboratory QC Technician?
The review process can be facilitated by QC management software, which helps the laboratory monitor the reliability and accuracy of results released in the POC setting.
There are a number of QC management programs available, however the following requirements should be sought after:
- Up to date peer group – Ideally a QC management program should have a peer group functionality to enable the comparison of results to other laboratories worldwide using the same lot of control, method and instrument. Peer group monitoring should be in real time, and therefore, should be updated daily.
- Multiple instrument registrations – the ability to register multiple instruments is vital in POCT as there will be a number of POCT devices through the POC setting that will need monitored.
- Online access – within a POC setting it’s important that results can be entered online, anywhere at any time. This also means that the lab manager can remotely log onto the software to view the QC results entered for specific POC devices throughout the hospital or beyond.
- Multiple user levels - Different user level accounts should be available so that lab managers can track results. This also ensures that each POC operator is performing appropriate maintenance, instrument calibration and is adequately trained to use the device.
- User defined acceptable limits - to be applied to QC results, so that results can automatically be rejected or accepted.
Indeed, major sources of error have been previously categorized to be commonly due to operator incompetence and a disregard for test procedures, and the use of uncontrolled reagents and testing equipment (5). Therefore, through using appropriate QC management software in the POC setting, the laboratory can reduce the level of risk and ensure accurate results are obtained.
It is important to remember that the benefits of POCT are only true if the results obtained are accurate and reliable, however, given the large number of POCT devices available on the market choosing an appropriate quality control plan for your instrument can be challenging. By following the guidelines outlined in this paper in addition to ISO 15189 and ISO 22870:2006 you can be assured that the management and overall results of your POCT devices will be of a higher and more reliable quality.
Randox Laboratories are able to help laboratories with their POCT requirements due to our ever-expanding portfolio of liquid ready-to-use controls suitable for use at the POC. Our range of controls suitable for use include Urinalysis, Blood Gas, Liquid HbA1c and more. Additionally, Randox can also supply Acusera 24.7 – our interlaboratory data management software – with real-time peer group updates, comprehensive yet easy to read reports as well as interactive and user-friendly charts. Our software is also capable of automatically calculating measurement of uncertainty and sigma scores automatically.
- ISO 15189:201, Medical laboratories -Requirement for quality and competence.
- O'Kane, Maurice J., et al. "Quality error rates in point-of-care testing." Clinical chemistry 57.9 (2011): 1267-1271.
- Kazmierczak, Steven C. "Point-of-care testing quality: some positives but also some negatives." Clinical chemistry 57.9 (2011): 1219-1220.
- ISO 22870:2006, Point-of-Care testing (POCT) – Requirements for quality and competence
- Meier, Frederick A., and Bruce A. Jones. "Point-of-care testing error: sources and amplifiers, taxonomy, prevention strategies, and detection monitors." Archives of Pathology and Laboratory Medicine 129.10 (2005): 1262-1267.
James Crilly - QC Marketing Manager - Randox Laboratories Ltd.