Point of Care Testing (POCT) is the delivery of a test at the point in time at which the result will be used to make a decision and taking appropriate action resulting in an improved health outcome. It is also known as near patient, bed-side, extra-laboratory, decentralised, and ancillary testing . It has been shown to reduce hospital stay time, reduce complications, and improve adherence to treatment .
Point of care testing is not a recent practice; many early diagnostic tests were administered at the bedside. However, analytical technology has progressed and multiple tests can be performed within minutes in a laboratory. Recently, this technology has been put into the hands of the staff near the patients . There are two types of technology, benchtop analysers and hand held devices. Bench top systems are just smaller versions of laboratory analysers but some steps are automated. Hand held devices are simple in appearance but complex internally, they can manage several tasks including, adding reagents, separating cells from plasma, and reading colour or other measures.
Results can be obtained faster, allowing for more immediate decisions meaning treatment can begin sooner. Patients can live a longer and higher quality life, helped by a reduction in the length of hospital stays.
Some benefits of POCT :
The main objective of Point of Care Testing is to generate results more quickly so that appropriate treatment can be provided, resulting in an improved patient outcome.
Accurate and reliable results can only be obtained if the patient and sample are treated correctly. Point of care testing is likely to be performed by staff with a limited technical background, so training and quality control are vital.
Proper analysis technique alone is not enough to ensure an accurate decision; any test will only be beneficial if the appropriate action is taken based on the result. The effectiveness of POCT is assessed in terms of the overall outcome of the patient.
There are three phases in the POCT cycle: pre-analytical phase, analytical phase, and post-analytical phase. About 90% of quality issues are attributed to the pre-analytical and post-analytical phases . These errors are mainly attributed to user error and can be caused by a number of issues including, selecting the wrong POCT device, not following manufacturer instructions, inadequate training, not adhering to appropriate QC practices, and many more.
The errors can usually be mitigated by implementing an action plan and ensuring it is executed exactly as designed, deviation from the action plan will lead to errors. Errors in POCT diagnostics can lead to misdiagnosis, improper treatment, costly follow-up procedures, and death.
Some strategies for improvement:
Internal Quality Control and External Quality Assessment is conducted to monitor the stability of the analytical measurement system and to alert the operator to a change that may lead to a medically significant error .
A study by Price, Smith and Bruel  was conducted on a number of labs over a period of time of up to 15 years. They discovered that test result performance improved with time and was associated with regular participation in External Quality Assessment (EQA) schemes and with the use of internal quality control (IQC) procedures.
Internal Quality Control
Internal Quality Control (IQC) is used to assess the day-to-day consistency of assay performance, providing quality assurance for patient results. IQC activities are among the ten most common POCT deficiencies. These may include performing and documenting quality control testing and taking the correct action for outliers . This poor performance could be attributed to how IQC is viewed in POCT; users may lack appreciation of the potential for errors and may see the analyser as infallible, they likely see IQC as an additional workload as opposed to part of their testing routine.
CLSI regulations require risk assessment for each stage of patient testing alongside an implementation of a quality control plan. Below are some suggestions for how IQC should be conducted for POCT.
IQC should be conducted when: a new lot of consumable is used; a patient result is queried; after maintenance; the device has been physically insulted. IQC should be conducted by the usual device operator so assurance can be provided for the whole testing process.
ISO 22870 requires POCT users should be trained in the theory and practice of IQC . Staff should be trained in every aspect of POCT including storage, preparation, frequency, documentation and basic troubleshooting.
QC material for POCT should be obtained from a third party provider and not rely on material provided by the device manufacturer, the benefits of which are well documented. It should also contain analytes at clinically relevant concentrations, be provided ready-to-use, and be stable at ambient temperatures.
All IQC results must be recorded with the date, time, user, decision to accept or reject, and any actions taken as appropriate. Locally assigned ranges alongside analyte-specific rules should be used to maximise error detection. An example of how IQC could be recorded and an action flowchart can be seen in Fig. A below.
There should be a protocol for required actions following a failed IQC. Any troubleshooting should be developed with knowledge of the most common errors and user capability.
A monthly review should be conducted to identify persistent failures and trends.
The cost of IQC may also be a factor in resistance to IQC, however, while it is difficult to quantify, the cost of not conducting it may be greater in terms of human harm. A whitepaper is available detailing IQC in POCT (download).
External Quality Assessment
External Quality Assessment (EQA) or Proficiency Testing (PT) involves running blind patient-like samples and comparing your results to peer results, in order to retrospectively monitor the accuracy of reporting. EQA samples should be treated as if they were a patient sample and therefore must be run by personnel who would normally use the device. This provides confidence in the reliability of patient test results. (Learn more about EQA)
Benefits of participation in an EQA programme include assessment of result accuracy, assessment over time, comparisons with instruments, methods and peers, and providing confidence in test results.
EQA for POCT is, in theory, similar to EQA in a large laboratory. There is a significant difference however, the POCT participants are usually health care professionals with little knowledge of laboratory medicine. A lack of understanding of the importance of EQA had led to a smaller percentage of sites participating than large laboratories.
A Good EQA Scheme
A good EQA scheme should offer:
Conducting EQA in POCT
Below are some suggestions for how EQA should be conducted for POCT.
EQA samples should be commutable, meaning they have the same numeric relationship between measurements procedures as is observed for a panel of patient samples (reacts the same as a real patient sample).
A fast turnaround time allows test system errors to be identified sooner and necessary corrective actions to be taken immediately with minimum disruption to the lab.
A regular review of past EQA results should be part of the cycle of quality.
A POCT EQA provider should be able to provide assistance when the user is having difficulties.
Individuals carrying out testing should have the correct knowledge to interpret results, choosing a scheme with easy to interpret results can help.
Internal Quality Control
Randox offer a number of controls suitable for Point of Care Testing applications:
Acusera Blood Gas Control
The Randox Acusera Blood Gas Quality Controls contain assayed target values for ten parameters, covering pH, pCO2, pO2, electrolytes, glucose and lactate. The material is provided in easy to open ampoules for added convenience and ease-of-use. The liquid ready-to-use nature of the control makes it ideal for use in point-of-care testing and on a wide range of blood gas instruments.
Acusera Liquid Cardiac Control
The Randox Acusera Liquid Cardiac control is designed to be both convenient and easy to use. The liquid ready-to-use format makes it ideal for both clinical laboratories and point-of-care testing. Assayed, instrument specific values are provided for an impressive 8 cardiac markers including, NT-ProBNP, D-dimer and Troponin ensuring consolidation and flexibility. Furthermore, an open vial stability of 30 days for all analytes helps to keep waste and costs to a minimum.
Acusera Liquid HbA1c Control
Liquid Urine Control
The Randox Acusera Liquid Urine quality control is designed to be both convenient and easy to use. The liquid ready-to-use format eliminates issues with pipetting and allows convenient storage at 2℃ – 8℃. Assayed instrument and method specific target values and ranges are provided for 18 commonly tested urine chemistry parameters.
External Quality Assessment
Randox offers RIQAS Point of Care, a simple EQA scheme designed for use in point of care settings. It is a single sample, single scheme programme featuring whole blood samples for authentic patient sample assessment.
RIQAS Point of Care
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