In Part 1 of this series, we discussed the importance of quality in the pre-analytical phase of Point of Care (POC) testing. In Part 2, we will cover the quality aspects impacting the analytical and post-analytical phases.
Traditional POCT operators are non-laboratory trained personnel lacking a firm grasp of laboratory principles and the importance of quality control (QC). One of the ways device manufacturers address the need to ensure the POCT cartridges and devices are acceptable for patient testing is to incorporate quality control rules in the device software.
Electronic quality controls prevent patient testing if QC has not been run or quality control values are outside acceptable ranges. For example, urine pregnancy cartridges/strips have an internal mechanism visible to the user to indicate whether quality control is acceptable. Other devices require operators to perform liquid QC at specified intervals.
Some POC devices utilize single-use cartridges having a quality control check built into the cartridge. "In-cartridge" QC provides a check of each reagent cartridge. This is important because operators sometimes carry cartridges in scrubs and jacket pockets outside of the required storage temperature, possibly affecting cartridge quality.
POCT devices that automatically run QC at specified intervals have sophisticated software programs to evaluate quality control data. Blood gas analyzers are multi-analyte analyzers with software that will not run tests on analyte channels failing QC checks.
It should be noted there is device software that will "lockout" an operator if QC has not been performed but also if the operator's competency is overdue and requires assessment. The competency "lockout" capability is an asset for large POCT programs needing to maintain competency across all users.
At first glance, one would think that testing is complete if the device passes the quality control checks, analyzes the sample, and delivers a result. However, that is not the end of the road in the journey to a successful POCT program. Unfortunately, the next step can be the most error-laden activity for operators manually entering or writing results in the patient's chart.
Manual entry of test results is problematic. One study of POC glucose testing reported 6930 events with 3.7% discrepant manually entered results over a two-year period. These were results used to determine insulin dosage and could easily lead to inappropriate patient treatment. Researchers also found the most frequent error was the switching, loss, or addition of digits. In the ongoing chaos of many emergency rooms, one can easily see how transcription errors occur, resulting in patient harm.
A key development in the POCT industry was the creation of POCT data management systems that were vendor-neutral. Today's POCT data management systems have the ability to interface with the electronic medical record (EMR) to download results directly into the patient's chart by docking at a base station. This capability eliminates the problematic manual entry step and virtually removes the possibility of transcription errors.
Some POCT systems now use wireless devices, eliminating the operator's need to "dock" the device at a base station to download results. Wireless systems, with appropriate security, increase the portability of the devices, and the bidirectional interface allows other data such as lot numbers and QC ranges to be downloaded.
With the increased use of QR codes and other types of barcodes on reagents and supplies, the quality of POCT programs has significantly improved due to the ability to track each item used in bedside patient testing.
Mentioned earlier in the discussion was the importance of quality control checks. The next question is, what happens when one of the quality checks fails? For many devices, the instrument will not allow testing to proceed unless some corrective action is performed, such as repeating QC or powering down the device. POCT program managers need to be able to follow or have documentation of the corrective actions taken by operators whenever QC fails.
There are several benefits a well-run POCT program brings to a small or large healthcare organization. For the emergency room, the ability to diagnosis a possible cardiac event earlier at the bedside allows immediate implementation of appropriate treatment. During the pandemic, POCT for COVID-19 has been critical in ensuring patient and employee safety at the doctor's office.
Bedside glucose testing increases the efficiency of nursing care by eliminating the need to send samples to the laboratory. Nurses readily embrace activities when there is a direct clinical benefit. POCT testing can also assist in other patient areas, such as computerized tomography (CT). Radiologists often request patients' creatinine levels before a CT scan, utilizing contrast media, can be performed.
POCT has brought convenience and efficiency to the patient care experience. However, there are numerous quality aspects of any POCT program requiring vigilance. The quality of operator training and competency should be constantly monitored to ensure proper usage of the devices. Storage temperature of reagents and supplies are areas easily overlooked but are can negatively impact test results. Quality is intertwined through all phases of successful point-of-care testing programs.
Despite the challenges, POCT will continue to be an integral part of the healthcare delivery model. Organizations would be wise to invest in a quality program that consistently delivers clinical benefits to their patients.
Photo Credit sinenkiy